f90daa1ee9005a0ceba5e893d43a56885fabb7db
49
Commits
| Author | SHA1 | Message | Date | |
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 Ilker ManapandClaude Opus 5.5
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20deb22dfa |
Let a node describe itself instead of being described by hand
Every agent file on the cluster named its own node, its own address, the path to llama-server and two weight directories — different on every node, kept true by hand, and not true: node05 carried "ram: 32g" beside a measured 31 GB, looked for weights in an empty directory while fetching them into another, and the other four never looked in theirs at all, so four nodes reported no disk. Growing a node's RAM would have gone unnoticed, because memory was read once, at registration. The agent now finds these out. Its id is the hostname, which is also the certificate's common name. Its address is the one on the route to the control plane, which the kernel picks for a UDP dial without sending anything. llama-server is looked for on PATH and then where release archives are unpacked. A missing nvidia-smi is a node without NVIDIA cards rather than a failed discovery — which also cut discovery short before InfiniBand on every CPU node not told to skip GPUs. Fetched weights land in /var/lib/llmgw-weights by default, and wherever they land is always looked in. Memory is read on every heartbeat, and installed engines are probed again each minute and sent when they change, so a VM given more RAM or a node given vLLM becomes a candidate without anyone restarting its agent. The control plane logs both changes, since "the node now qualifies" is the answer to why a model placed an hour after it was asked for. What is written still wins. The agent file shrinks to the control plane's addresses and the TLS files, the same on every node; onboarding writes only the overrides it was given. What cannot be found stays configuration: which fabric an adapter is on, because OpenSM's default prefix is the same on all of them. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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03e38e7dda |
Carry the profile fingerprint to the agent and back
The stale-profile flag could not fire where it matters. The control plane keeps no record of a running replica across its own restart — it rebuilds them from what the agents report — and adoption left the fingerprint empty, so every replica read as unknown afterwards. That is precisely the moment the catalog is most likely to have been edited: change the configuration, restart the server, and nothing would ever say the fleet disagrees with it. The fingerprint now travels with StartShard, the agent keeps it beside the pool and fabric it already echoes back, and adoption takes the replica's version from the agent rather than from the catalog it is about to be compared against. An agent too old to report it sends nothing, which still reads as unknown rather than as matching. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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40f5c930c4 |
Say when a replica is running an edited profile, and check a source from the web too
Two defects, both of the same kind: something the CLI knew and the rest of the system did not. A profile can be edited while a replica is running against the old one. The reconciler deliberately leaves it alone — churning a replica that is serving costs more than the imperfection — but there was no way to see it, so the cluster could disagree with its own configuration indefinitely and read as healthy. Profile now carries a fingerprint, a replica records the one it was placed with, and both the API and `ctl replicas` say "stale profile" when they differ. An empty fingerprint is not stale: it means a replica adopted from an older agent, which is unknown rather than wrong. Adding a model from the admin page skipped the source check `ctl model add` has done all along, so a typo or a mirror that is down became a replica failing on a node minutes later, with an error naming the node. The check moves out of the CLI into a package both use. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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8fd4c1392d |
Stop handing the same memory to two models
Placement compared a profile's memory requirement against the node's total, so a 31 GB machine accepted two models that each declared 15: each was asked about on its own, and nothing recorded that the first had claimed anything. GPUs were never handed out twice this way — they are tracked as claimed indices — and memory was, because the allocation carried no figure for it. An allocation records what its profile asked for, and eligibility subtracts what a node already owes before comparing. The rejection names both numbers, because "needs 15" beside a 31 GB machine reads as a bug in the scheduler rather than a full node. Declared, not measured. A profile that says 15 is treated as holding 15 whether the process has touched that much yet or not — the alternative is deciding against what a model has grown into so far, which is wrong every time one is still loading. Zero is nobody said, and claims nothing. Counting it would let one undeclared model make a whole node look full. Adoption after a restart re-reads the figure from the catalog rather than from the agent: what a profile asked for is not something a running process reports, and a control plane that forgot every claim on restart would put a second large model onto a node already full of the first. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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d998ea7ef5 |
Let a model say what it is for
A gateway serving nine models offered nine names and nothing to choose between them. /v1/models is the only view most clients ever have, and it listed ids. Models carry a description now: written when the model is added, shown on the dashboard and sent to clients in /v1/models. Written rather than derived. A registry offers a pipeline tag and a wall of README, and neither answers the question somebody picking from a list is asking — which of these should I send this request to. "General chat, strong Swedish; slower than the 8B" is not in any metadata field. It is optional, and absent means absent rather than an empty string in the response: a model nobody described should read as undescribed, not as described with nothing. On the dashboard it sits under its row rather than in a column. A sentence in a table cell either wraps every other column into a stripe or gets cut off. Co-Authored-By: Claude Opus 5 (1M context) <moreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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2acd794022 |
Stop placing engines on nodes that do not have them
A node's registry holds an adapter for every engine whether or not its binary exists, the agent never said which were installed, and placement carried an Engine field it had never once read. So a vLLM replica was as happily placed on a node with no vLLM: the node registered healthy, the shard failed minutes later with "executable file not found" in the engine's own words, and the reconciler tried again. That is how fifteen gigabytes of safetensors reached this cluster's mirror before anybody noticed it had no card and no vLLM to run them with. Agents now probe what is installed and report it — the protocol has carried engine_versions since it was written and nothing ever filled it in. Placement filters on the key set, `ctl nodes` has a column, and the mirror page's serve warning is a fact instead of a guess about cards, which would have waved through a fleet of eight-GPU nodes that never had vLLM. Probing resolves binaries and runs none of them. The first version asked each engine for --version, which is fine for an engine and not fine for the wrapper scripts people put in front of one: a script that shifts past flags it does not recognise and then execs the server will start an inference server, at agent startup, on every node. The agent's own test suite installs exactly such a script and caught it. So presence is a path lookup, and the version is left to `ctl engine-check`, which is run by somebody who meant to run the engine. SGLang is the exception and has to execute, because a module has no path to look up — but the command is llmgw's own one-line import rather than the engine's launcher. Its exit code is the answer: python3 is on almost every machine, and treating a failed import as "installed" reported SGLang on every node in a fleet that had none, which is the failure being fixed, inverted. Probed once, not per reconnect, and bounded by the context that registration waits on: an agent that cannot reach the control plane is worse than one reporting an incomplete list. A node that reports no engines at all is not excluded anywhere — by placement, or by the page. That is what every agent older than this reports, and emptying a fleet on a control plane upgrade is a worse failure than the one being fixed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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a83493bddb |
Show what a group spent, and fix the reports that never ran on PostgreSQL
Quotas can be written on an organization, a team or a project, and nothing could show what any of them had used: usage came back per key, per user and per model only. A quota whose consumption cannot be seen is one nobody reviews until the day it refuses somebody — and since the previous commit made a group quota a shared pool, it is now a number several people are spending against without being able to look at it. `llmgw ctl usage --by team` sums every key beneath each group, with the budget that level sets beside it. Beside it, and only when that level sets one. A team bounded by its organization's budget has none of its own, and printing the organization's against each of its teams would read as though each had that much — the exact misreading this work exists to remove. Joined through api_keys rather than read from usage.project_id: that column records where the key was when the request was served, while the quota is written against the tree. They agree until a key is moved, and a report that disagrees with the limit shown beside it is the useless one. Three existing reports were fixed on the way, all failing on PostgreSQL and all passing in tests, because the tests run on SQLite: column "k.name" must appear in the GROUP BY clause (UsageSince) column "us.email" must appear in the GROUP BY clause (UsageByUser) column "usage.ts" must appear in the GROUP BY clause (UsageBuckets) SQLite picks an arbitrary row for an ungrouped column and carries on; PostgreSQL refuses. The first two were selecting names they had not grouped. The third grouped "ts / ?" while selecting "(ts / ?) * ?", which PostgreSQL matches as text and so saw a bare ts — it is grouped by ordinal now, the same expression by construction. The dashboard's usage charts have been empty on the cluster this whole time, with the reason only in the log. All four queries were run against the cluster's own PostgreSQL before this was committed, because passing on SQLite is what they were already doing. The grouping level picks from a fixed table of levels rather than being interpolated, so an unknown one is an error and not a fragment of SQL. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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3aa250428a |
Keep what a benchmark found out, instead of leaving it in a terminal
`ctl bench` has always been able to work out what one replica can serve — it ramps concurrency until the SLO breaks and reports the last level that held. It printed that and nothing kept it, so the one number saying what a replica is worth lived in whoever ran it's scrollback. Everything downstream then had to guess: admission applies a single global default for healthy queue depth, and sizing a model against real demand had nothing to size against. `ctl bench --save` records it; `ctl capacity` reads it back. Keyed by model and profile. Capacity belongs to the hardware and the engine arguments as much as to the weights, so the same model on CPU and on an H100 are two numbers, and one key would overwrite the other on every run. The profile is looked up from the replica rather than asked for, because the control plane already knows which profile answers on which endpoint and a measurement filed under the wrong one is worse than none. A target that is not a replica — the gateway, usually — is refused with that said: benchmarking the whole path is worth doing and says nothing about the hardware. The conclusion is stored, not the ramp. Every level and its latencies are worth reading once while judging whether the run was sound; keeping them would grow without bound as a model is re-benchmarked. Re-measuring replaces. A second run is a better answer to the same question, not another data point, and keeping both would leave a reader choosing between numbers with no basis for the choice. The SLO and the date are stored with it. Capacity means nothing without the target it was measured against, and hardware and engine builds change — a measurement is an observation with a date on it, not a fact about the model. A failed save is reported and not fatal: the run has already cost the GPU time. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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707d774c76 |
Change a model's replica count without editing a file on the control plane
The count is scaling.min, and until now the only way to change it was to edit server.yaml on the host and restart — or, for a model added at runtime, to remove it and add it back, which means having its whole definition to hand. `llmgw ctl scale <model> --min N` instead. Only the scaling block moves: everything else is read back from what was stored and written out untouched, so changing a number cannot quietly become a redefinition. The catalog is rebuilt and validated before anything is written, as in Add. A max below a min is refused with the stored definition untouched — persisting a rejected change would come back on the next restart as a catalog that does not build. The answer reports the scaling in force rather than the request. The catalog fills in a max that was left out, and a caller echoing its own request would print a number the cluster is not using. A model declared in configuration is refused, for the reason Remove already refuses one: the YAML is read on every start, so the new count would hold until the next restart and then silently revert. A cluster disagreeing with its own config file is worse than an error saying where to edit. The help says what --max does, because it is not what it looks like: a model with a minimum runs exactly that many and nothing scales it up under load, and an on-demand model loads one replica however high its max. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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a35e8796d2 |
Carry a download's progress to where somebody is looking at it
The agent has always logged a percentage as it fetches weights, with a comment saying a replica pulling a hundred gigabytes and one that is wedged look identical from the control plane. They still did: the log is on the node, and the node is not where anyone is looking when a replica has been starting for ten minutes. Progress now rides on the shard status and appears under the replica in `ctl replicas` — a line rather than a column, because most replicas are not downloading anything and a column would be empty for all of them. It is deliberately not a state transition. Treating each chunk as one would re-mark the shard as starting on every report and reset the timer that decides when a slow start has become a failed one, so an hour-long download would keep a doomed replica alive indefinitely. It arrives on its own method for that reason, and a real transition clears it — otherwise a finished download sits in the listing at ninety-nine percent under a shard that has been serving for an hour. Watchers are keyed by source rather than by shard, because a fetch is single-flight: eight shards starting together produce one download and all eight are waiting on it. No percentage is invented when the server sent no length. One that stops moving is worse than a byte count that keeps rising, so the field is absent and the listing says "so far". Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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4ba84fa90e |
Let an agent find the leader instead of being told one address
The second half of leadership. A standby that refuses to place but still holds an agent's stream is worse than useless: commands travel down the stream the agent opened, so the leader's placements fail with "no agent connected" for a node that is plainly connected. So a standby refuses the stream, before reading the opening message, and says why. And an agent takes a list rather than an address, trying each in turn — a standby refusing, a stopped control plane refusing the connection and a crashed one never answering are the same thing from a node, and the answer to all three is somewhere else. `server` and `servers` are both accepted, with `server` first when both are given: every agent configuration written before there could be a second control plane names one address, and an operator adding a standby expects the one already working to stay preferred. With a single address the behaviour is exactly what it was, including the backoff — which is skipped only while there is another address that has not just been tried, because the delay exists to stop hammering one control plane and the next one has not been hammered. Removed a check that asked whether one field was empty, which is how the first run of these tests failed: the list was populated and `server` was not, and an agent configured entirely correctly was refused by its own validation. The tests run a real agent against a real service over h2c. The first attempt used a plain HTTP server, and the refusal arrived as an HTTP/2 framing error that said nothing about why — which is exactly what an operator would have seen. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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5b5e61cb97 |
Stop a second control plane from placing work behind the first's back
The first thing HA needs that a shared store does not give. Two control planes against one store both reconcile: both see a model wanting two replicas and none running, and both place. The model ends up with twice what it asked for, each replica holding GPUs the other's inventory believes are free — and nothing crashes to say so. A lease in a table rather than a lock held by a connection. PostgreSQL has advisory locks and SQLite has nothing like them, and this store keeps one set of queries for both; a row with an expiry works everywhere, and it survives a leader being powered off rather than asked to stop, which is the case that matters. Taking and renewing are the same statement, so the two cannot disagree about what a held lease looks like, and it is one statement, so two processes racing cannot both believe they won. The owner id is random rather than the hostname. A hostname would let a restarted process match its own stale lease and believe it had been leading all along — including through the gap that made it restart, during which somebody else may have taken over and started placing. A store that cannot be reached is not evidence that somebody else is leading, so an unreachable store keeps the claim. Two leaders is worse than one, but no leader means nothing is placed and nothing is evicted, and a brief database blip should not stop a cluster healing itself. Unset means leader. Every deployment that existed before this, every single-control-plane install and every test acts unconditionally, with nothing to configure. The same seven assertions run against both backends, which is how the test harness was caught inheriting a lease between subtests — it passed on SQLite, where each subtest gets a fresh file, and failed only on PostgreSQL. What this does not yet do is move agents. A standby holding an agent's stream is one the leader cannot command, so failover is degraded rather than clean until agents know more than one address. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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45e913bd10 |
Refresh disk and weights while the agent runs, not once when it starts
Found by answering "where can we see this live". `ctl weights` was offering a file for deletion that I had deleted two days earlier, and the node's disk figure was the one it had when its agent started. Discover() is called at registration and nowhere else, so both were frozen. Disk is a fact about a moment, not about a machine. Sampled once, the figure is wrong on exactly the node worth watching — the one busy filling up — and it stays wrong until that agent restarts. The heartbeat already refreshes GPU memory for the same reason, with a comment about noticing a foreign process "after registration"; disk belonged beside it and I did not put it there. The stale list cut both ways. A model fetched after registration was invisible until a restart, so placement could not prefer the node that had just spent ten minutes downloading it, and the disk check could not see the space it used. Storage goes in every heartbeat, being a few numbers per filesystem. The file list goes only when a fingerprint of paths and sizes changes, with a flag saying the list is meant — without that, an empty list would be ambiguous between "this node now holds nothing" and "nothing to report", and the second reading would empty a node's inventory five seconds after it registered. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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774e134ed1 |
Refuse a node with no room, and take back only what llmgw put there
Two halves of the same problem: nothing stopped a model being placed on a node that could not hold it, and nothing ever removed the weights of a model that had been deleted from the catalog. Placement now has a disk check, shaped exactly like the memory one it sits beside, with one addition: it is skipped on a node that already holds the weights. A node holding the file needs no room for it, and without that the node best placed to run a model — because it already has it — is the one most likely to be rejected, since holding the file is what used the space. Reclaiming is the dangerous half, so the whole design is about what it will not do. llmgw deletes only files it fetched itself, and that is a calculation rather than a heuristic: the cache name is a hash of the source, so the set of wanted files can be computed from the catalog exactly. Anything without that name was put there by an operator — scp, a shared mount, a copy by hand — and is none of this system's business however unreferenced it looks. A model that took a week to copy must not be removable by a command someone ran to tidy up. The node checks every path again before unlinking it, and that duplication is the point. The control plane knows the catalog; the node knows its disk. A control plane that is wrong, newer than the agent, or tampered with must not be able to talk a node into deleting something, so the agent refuses anything outside its own cache directory or without the cache name — including a path that tries to traverse out of it. Listing is the default and deleting takes --collect. The summary says "asked to remove", because each node decides, and one that refuses a path it cannot prove it fetched is this working rather than failing. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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753f4e3265 |
Let a node say how much room it has left
Disk was the one resource nothing reported. `statfs` was already being called on every model directory, but only to ask whether the filesystem was a network one — the free space it returns in the same struct was thrown away. So the only way to find out why a node was filling up was to ssh to it, which is what this system exists to avoid. Reported per filesystem rather than per configured directory. Free space belongs to the disk, not the path: two model directories on one disk are one pool of bytes, and counting them separately would let the control plane add 24 GB to 24 GB and place a 40 GB model on a node that has 24. Shared filesystems are summed separately from local ones and left out of a node's own total. Space on a filer belongs to everyone mounting it, so twenty nodes would otherwise each report the same free terabyte, and a scheduler would place twenty models into room for one. Nothing reported means nothing is known, everywhere: an agent too old to send storage and a node with no model directories both send nothing, and both must read as unknown rather than as a full disk. `ctl nodes` and the dashboard show a dash, the metric is absent rather than zero, and a missing directory — which is what an unmounted filer looks like — is skipped rather than reported as having no space. Shown as free out of total, because the first is useless without the second: 8 GB free is comfortable on a 10 TB filer and nearly full on a 10 GB root partition, and only the second stops a model being placed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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9b32531ce3 |
Stop an idle model to make room for one somebody asked for
On-demand loading worked right up to the moment the cluster was full and then stopped meaning anything: the model somebody had just asked for could not be placed, and the cards were held by a model nobody had asked for in an hour. That is the only situation in which any of it matters. Deliberately narrow. Only idle replicas of other on-demand models — a model at min 1 is a promise that it stays up, and breaking it to serve a different request would make every guarantee in the catalog conditional on load. Only single-node replicas, since evicting a multi-node one frees several machines and costs tens of minutes to rebuild. One at a time, because freeing everything that qualifies would empty a cluster for a request that needed one node. And never a replica with no reported usage: after a router restart that is all of them, and unknown is not idle. Writing the test found a gap the feature had rather than a bug in the test. Two on-demand models on a cluster with room for one would take turns evicting each other, at a model load per cycle — worse for both than one of them waiting. A replica is now safe from eviction for a few minutes after it starts serving, which bounds that. Which in turn found a latent bug: deriveState stamped ReadyAt with time.Now() inside a package that has an injectable clock, so the new lifetime rule could not be tested at all — the fake clock said three minutes and the wall clock said eight months. Invisible while nothing compared ReadyAt to anything. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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7fe59bd5fb |
Load a model when someone asks for it, and stop it when nobody does
The feature the idle tracking was for. A cluster with more models than GPUs can now hold every model in its catalog and only the wanted ones in its cards: min 0 with a max above it means load on demand, and once nobody has asked for idle_timeout the replicas stop and the cards go back. No new field, because min 0 max 1 already reads correctly — keep none running, allow up to one. Which made min 0 max 0 meaningful for the first time: configured and deliberately not running. normalize() used to fill a zero max in, on the reasonable ground that a model with no maximum cannot run; that would now silently turn every switched-off model into an on-demand one, including the ones already written that way in this cluster's own configuration. A model with no scaling stanza stays off for the same reason — defaulting it to on-demand would let any client request start a 70B nobody intended to run. The one real decision is what happens to the request that triggers a load. Refusing makes the feature useless, since the first request for every model fails; waiting without a bound turns a request into a job, and a client that budgeted thirty seconds holds a connection for ten minutes. So it waits briefly and then says what is happening — 503 with Retry-After and "the model is loading", which is a different answer from "no endpoint serves this" and produces different client behaviour. An unknown model still gets the unknown-model error, or on-demand would turn every typo into "loading" and the useful message would disappear. Use keeps a model alive rather than only the request that started it, without which the timer measures time since the load and a busy model is evicted on schedule however hard it is working. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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b619546516 |
Stop trusting hardware facts that were never checked
Three places where the system took the infrastructure's word for something and would have failed silently on real hardware. A declared fabric adapter that is not on the node. Fabric membership has to be configuration — OpenSM's default subnet prefix is identical on every fabric, so a matching prefix proves nothing — but taking it entirely on trust was a different mistake. A typo, or a card that enumerated differently after a reboot, produced NCCL_IB_HCA naming an adapter that does not exist. An adapter with no ACTIVE port. Physically linked with no subnet manager sits in INIT: it looks healthy to anything counting adapters, carries no data, survives a reboot, and looks like a software problem. Discovery had recorded port state all along and placement only ever asked whether a fabric had any adapters listed. Both end the same way — the replica starts, passes its health checks, and hangs on its first all-reduce, which is the failure the fabric invariant exists to prevent arriving through a door nobody was watching. The agent now compares declared against discovered, where both are visible for the only time, and does not advertise a fabric that cannot carry traffic. The reason is logged on the machine that knows it, because the operator who typed the adapter name is the only person who can fix it. The fabric's rate is the slowest active link, since a collective runs at the speed of its slowest. And NVLink topology, which no published binary could see. NVML is its only source, the bindings need cgo, and CGO_ENABLED=0 is deliberate so the portable binary runs on an older libc. The cost was silent: tensor groups fall back to the lowest free indices, which is right on an SXM board with NVSwitch and wrong on a PCIe box where bridges pair specific cards — a group straddling two of them runs several times slower and nothing says so. Releases now also publish an nvml build for those nodes, and llmgw_gpu_nvlink_peers makes the difference visible: a flat zero across a fleet means the topology is unknown rather than absent. A test that declared mlx5_0 and mlx5_1 on a node whose sysfs held neither had been passing, because nothing compared the two. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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42fd0aa31e |
Export what the cluster is made of, not only what it is serving
The router published twenty-two metric families about requests, endpoints, admission and scoring — everything about traffic and nothing about the machines carrying it. There was no way to graph GPU usage, watch a node go unhealthy, see a fabric fill up, or answer "was the cluster full at the time", which is the first question anyone asks after an incident. The agents exported nothing at all. Exported by the control plane rather than by each agent. It already holds every number: hardware arrives at registration and state on each heartbeat, so this is a map read away. One scrape target for a fleet of hundreds, no Prometheus configuration per node, no firewall rule per machine, and nothing new running on the nodes. On the same /metrics as the traffic figures, because correlating "the cluster was full" with "requests were queueing" should not need two systems. A collector rather than gauges kept current by a ticker: the numbers are derived from state that already exists, so computing them when asked is simpler than maintaining a copy that can drift, and nothing runs between scrapes. GPU utilisation is new, and is the number people actually watch. Memory used says a model is loaded; this says whether it is doing anything, and a fleet at ninety percent occupancy and two percent utilisation is a fleet holding models nobody is asking for. Adding it caught two things. utilization.gpu goes last in the nvidia-smi query and is optional, because a driver too old to know it returns a shorter row — requiring it made an llmgw upgrade silently stop discovering GPUs on an older node, which is far worse than not knowing how busy a card is. And I gave the new protobuf field number 14, which ecc_errors already had; buf lint is why that was a moment rather than a corrupted wire format. Absent is kept distinct from zero throughout, for the same reason as everywhere else here: an unreported utilisation shown as a flat zero reads as an idle fleet rather than a missing measurement, and a replica nothing has reported would be the most idle thing in the cluster. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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c13c567cc5 |
Know where the weights are, without owning the storage
Storage will be different at every installation — Lustre, NFS over RDMA, an image exported with SRP or NVMe-oF, local NVMe, an rsync — so llmgw observes it rather than managing it. An agent told which directories to look in reports what it can see; how the files got there is nobody's business here, and a node told nothing reports nothing and behaves exactly as every node did before this existed. That fact buys two things. Placement prefers a node that already holds the model over one that must first move tens of gigabytes, as a preference and never a filter: fetching them is a valid answer, and refusing to place would turn a slow start into no start at all. And ctl status shows what each fabric holds. Per fabric because fabrics are not connected to one another. Weights in ib-a are not weights in ib-b — the only path between them is the management network — so a model seeded into one fabric leaves the rest of the cluster unable to serve it without a slow copy, and nothing said so before now. One shared filer counts the same as twenty local copies, because "can this fabric serve it" is the question being asked. Three distinctions the tests hold to, because each is a way to get this quietly wrong. A node that was never asked to look must rank with one that looked and has nothing, or enabling the feature on a single node would drain every other. An empty directory is not weights, because a half-finished download looks exactly like one and would send placement to a node whose engine then fails to load. And local storage is never mistaken for shared: a filer read as local costs an unnecessary copy, while local read as shared would have the cluster believe a model is everywhere when it is on one node. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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331de9b495 |
Add and remove models from the command line
The last piece of not restarting a control plane to try a model: llmgw ctl model add -f qwen-coder-32b.yaml llmgw ctl model remove qwen-coder-32b The file is the same YAML a model takes in server.yaml, read by the same koanf parser through the same tags, so an entry moves between the two by being copied and a field that works in one cannot silently mean nothing in the other. Wired only when there is a store. A control plane without one says so rather than accepting a model that vanishes on the next restart, which is the kind of success that wastes an afternoon. At startup the catalog is rebuilt from configuration plus what was stored, so models added before a restart are still there after it — without that the whole feature would be a slower way to lose work. Every failure adding a model is the definition being wrong — a collision, a missing fallback, a profile that cannot be placed — so they are 400s. A 500 would send someone to the server's logs for a mistake in their own file. The actor comes from the caller and is kept with the row, so a catalog that has grown over months can say where each entry came from. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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277add5ccb |
Keep runtime models, so an added model outlives a restart
The catalog can change while the cluster runs; this is where a change goes so it is still there tomorrow. Models declared in configuration and models added at runtime are two sources on purpose: config-as-code stays declarative and under review, and the database holds what someone added to try it. Configuration wins every conflict, and the direction matters. A request for a reviewed production model must never be answered by something added from a laptop, so a stored model colliding with a declared name is refused when it is added. A declared model cannot be removed at runtime either — it would return on the next restart, leaving the cluster disagreeing with its own config file until then, which is a worse answer than refusing and saying where to edit. The whole catalog is built before anything is written. A model naming a missing fallback, or colliding, or malformed in any of the ways catalog.New refuses, is rejected rather than persisted and then skipped forever after — a model that looks added and never appears is the worst outcome available. Removal is checked the same way, because another model may fall back to the one being removed, and a fallback pointing at nothing is discovered during the outage it was meant to cover. At startup each stored model is validated on its own against what is already accepted, so one bad row is skipped and named rather than taking the cluster with it. The declared models are precisely the ones that must survive that. Catalog types now carry json tags mirroring their koanf ones, so a stored definition is the same shape as the YAML someone writes. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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1c57a4e378 |
Let the catalog change while the cluster is running
Adding a model was an operator procedure with downtime: edit a file on the control plane, restart it, wait out the settling window, watch replicas churn while adoption catches up. I did that eight times in a day, and one of the restarts cost two minutes of outage while stalled replicas timed out. None of it was necessary. The reconciler already compares desired against actual on every pass, so a new catalog is simply a different desired. A Catalog stays immutable — New is the only way to build one and it refuses an invalid one — and what changes is which immutable catalog is current. Readers take the pointer and finish their operation against it, so a swap mid-request is invisible rather than a race. The router is told rather than asked, the same shape as the endpoint list and for the same reason: a push happens once per change, a pull would happen once per request. The router still seeds from configuration as well as being pushed to. A router with a static endpoint list and no control plane is a supported mode and has nothing to push it a catalog; without seeding it would resolve no model at all. Which turned up a bug that was latent while catalogs were fixed. reconcileModel only ever visits models that are in the catalog, so a replica whose model had been removed was visited by nothing: it kept its GPUs, kept counting, and kept running an engine for a name no client could ask for. The endpoint publisher skipped such a replica with the comment "the reconciler will tear it down", which was not true. It is now, and the comment says what actually happens instead of what was assumed. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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9d8cd5e284 |
Track which replicas are actually being used, and summarise the fleet
Two things a cluster with many nodes and many GPUs needs that were missing, and they are the same thing seen from two distances. Idle tracking. The control plane knew what was placed and whether it was healthy, never whether anyone wanted it — so on a fleet with more models than cards there was no way to answer the first question anyone asks, which is what can I stop. The router is the only thing that knows, so it now reports it: a timestamp written in Acquire, where a request already meets an endpoint under a lock already held, and collected once a tick as a map. That shape is the point. Per-request notification would be a firehose carrying one bit — the newest timestamp wins — and this costs the same on four replicas as on four hundred. It travels through an interface in the direction opposite EndpointSink, for the same reason that one exists: the control plane decides what should run, the router knows whether anyone wants it, and neither should need to be in the other's process to say so. Unknown is kept distinct from idle throughout. A router that has just restarted knows nothing, and a zero timestamp would be the oldest idle replica in every comparison — so one restart would nominate an entire fleet for eviction. Absent from the map, "-" in the table, negative in the JSON, and IdleFor returns a second value rather than a duration anything could act on by mistake. ctl status. A per-node listing is right for four nodes and wrong for two hundred: how full am I, what is broken, what is holding cards nobody is using are aggregates, and reading them off a long table is a chore, which means it gets skipped. Capacity per GPU class with usage bars, free whole nodes per fabric — the number that decides whether a multi-node replica can land, since free cards on the wrong fabric are not capacity for a model that spans nodes — replica and model counts, models that cannot be placed, and what has gone unasked-for. Derived from the same state the tables show, so it cannot disagree with them. Unhealthy GPUs count as neither used nor free, because counting them free is how a cluster looks like it has room it does not. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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4f9fef2a98 |
Make settling outlast an agent reconnect backoff
The window worked on the cluster and settled on the wrong answer. After a restart node05 registered in one second and the other four arrived seventeen seconds later, because a disconnected agent reconnects on a backoff that reaches thirty seconds. A five-second steady period called a fleet of one settled and resumed placement while four nodes were still coming — the exact situation the window exists to prevent, reached by being impatient about it. Nothing was misplaced this time only because the model that wanted placing needed two nodes on a fabric and could not have it. With a single-node model it would have landed on node05 and stayed there. A minute now, and steady for half of it rather than a quarter. Adoption is unaffected, so a restart still recovers everything already running immediately; only new placement waits. The test that covers it drives Reconcile the way the ticker does, because the node count is noticed on a pass rather than the instant a node appears — which the first version of the test got wrong and hid. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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7e65cdf5c9 |
Fix the adminapi tests the settling window broke
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Ilker ManapandClaude Opus 5
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e05d5d48ee |
Do not place on a fleet that has not reported in yet
A control plane that has just started knows nothing, and its first reconcile tick runs before any agent has registered. "needs 2 nodes on one fabric, but no node reports a fabric" in the log is that, and it looked harmless because adoption catches up. What is not harmless is placing on the fraction of the fleet that happened to report first. After one restart both replicas of qwen2.5-0.5b landed on node04 — the only node registered at that instant — when four were coming, and nothing ever moved them, because the desired count was met. Placement now waits, and leaves by either of two doors, because either alone is wrong. Waiting for the window to expire would cost that much downtime on every restart even when the whole fleet reconnected in a second; waiting only for the node count to stop changing would hang forever on a cluster whose nodes never all come back. So: the count holds steady for a quarter of the window, or the window expires. Only placement waits. Node expiry, stuck-replica expiry, draining and reaping all stay correct on a partial fleet, and adoption in particular must not wait — it is how a restart recovers what is already running, and delaying it would leave live engines unaccounted for exactly while the reconciler decides what to build. The window is paid once per process. A node joining a running cluster is an ordinary event, not a reason to stop placing. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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3081c6f69b |
Place on nodes that can actually hold the model
Placement had no idea how much memory a node has or a model needs. A CPU profile has no card to be free, so eligibleNodes accepted every ready node: Qwen2.5-Coder 14B, whose working set is about 24 GB, would have been placed just as happily on one of the 8 GB nodes, which reports itself perfectly healthy right up until the OOM killer arrives. node_selector was yesterday's stopgap and it is the operator restating by hand something the system can know. Agents now report MemTotal, profiles declare min_memory_gb, and placement filters on it, naming what was short — "has 8 GB of memory, needs 24" is actionable where "no candidates were considered" is not. The label selector stays, because "this node is for coding models" is a real thing to want to say that memory does not express. Two deliberate non-exclusions. A profile with no requirement fits anywhere, which is every profile that exists today. And a node that reports no memory is still usable: an agent older than the field says nothing, and letting a control plane upgrade quietly empty half a fleet is a worse failure than the one this prevents. ctl nodes grows a MEM column showing "-" rather than 0 for a node that did not say, because an old agent is not a small machine. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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e9fe3ad379 |
Know how big a model's context is, and what it can do
Three things the gateway did not know about its own models, all of which surfaced this week as somebody else's bug. Context length. Nothing read it, /v1/models did not publish it, and an over-long prompt was not refused: it was admitted, scheduled, given a replica and a slot, and rejected by the engine in whatever shape that engine chose. A client sizing prompts from /v1/models had nothing to read. It is now declared per model, published when known, and checked before authentication work or a queue slot is spent — with a ten percent margin, because the estimate is bytes over four and being a few percent out must not turn a valid request into a refusal. Capabilities. The gateway forwards a tools array to any model, and one that cannot use them answers in prose; every OpenAI-compatible client then behaves as though the model is broken, and the only way to find out was to try it. Declared rather than discovered, because no engine will say — which is why these are claims, and why the next commit makes engine-check verify the tool-calling one instead of trusting it. And a bug found while wiring the first: the token estimate was taken from the routing prefix. That prefix stops at 2 KB by design, so every prompt above it estimated as 512 tokens however long it really was, and TPM limits undercounted exactly the requests that consume the most. Prefix routing wants a bounded head of the conversation; a token estimate wants all of it. They are now separate functions, and structured multimodal content counts rather than measuring zero. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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8a894af1ca |
Let a profile say which nodes it is for
Agents have reported labels since the beginning and nothing read them. That
was survivable while every CPU profile was a 0.5B model that fits anywhere,
and stops being survivable with a 14B one: a CPU profile has no card to be
free, so eligibleNodes accepts every ready node, and placing Qwen2.5-Coder
14B on one of the 8 GB nodes would OOM a machine that reported itself
perfectly healthy.
Nothing in the inventory says how much memory a node has, and inferring it
would be guessing at the wrong layer — the amount that matters is the
model's working set, which the scheduler does not know either. So the
operator says which nodes a profile is for, with the labels that already
exist:
node_selector:
ram: 32g
A rejection names the label it did not find, because "no candidates were
considered" is not something anyone can act on and "does not carry ram=32g"
is. An absent selector constrains nothing, which is every profile that
exists today, and there is a test that says so.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Ilker ManapandClaude Opus 5
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6f3bde099e |
Let a multi-node replica be adopted one agent at a time
A replica spanning two nodes is reported by two agents, registering
separately about a second apart. Adoption assumed one call carried a whole
replica, so the first half was adopted with WantShards=2 and immediately
failed for "replica has 1 of 2 shards" — and when the second node
registered, its half was condemned as unclaimed because the replica was
already written off.
big-model therefore could not survive a control plane restart. Seen after
today's deploy: adopted, failed, both halves stopped, rebuilt from
scratch, backing off 9s, 20s, 38s, and never becoming ready. The first
reconcile tick also runs before any agent has reconnected, which is the
harmless-looking "no node reports a fabric" that precedes it.
Two changes. Adopt merges a group into a replica it is still assembling
instead of treating it as a competing claim, and takes the endpoint from
whichever group carries rank 0 — the leader's agent is not necessarily the
first to register. deriveState leaves a replica that is short of shards
while still assembling in Starting rather than Failed, which puts it under
the startup timeout that already exists: a sibling that never arrives
still fails, one second later than it used to rather than one second
before its sibling reports in. AdoptedAt is cleared once the replica is
whole, so losing a shard after that is a failure again.
The existing multi-node adoption test passed throughout, because it hands
both shards to a single Adopt call — which no caller makes. Same shape as
the agentsvc bug in
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Ilker ManapandClaude Opus 5
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72b03a1a1c |
Say which model is simulated instead of letting it look broken
big-model runs on the sim engine, whose whole vocabulary is the Greek alphabet, cycled at a fixed rate until max_tokens. That is what it is for: with no H100s it is the only thing exercising the TP8 two-node path, the fabric invariant and rebuild-after-node-loss. The output is the point. What was wrong is that nothing said so. /v1/models returned it with owned_by "llmgw", identical to the real model, and the chat picker sorted purely by name — so "big-model" led the list, was preselected by the browser, and anyone who typed a question and pressed Send got Greek letters back with no explanation. Reported as the model spitting out crap, which is a fair reading of what it looks like from outside. Simulated is derived from the profiles rather than configured: an operator who adds a sim profile and forgets a flag would be shipping placeholder text under a real model's name. A model counts as simulated only when every profile is, because one real profile means the request can still come back as inference. The marker on /v1/models is owned_by "llmgw-sim", which is already what the sim engine calls itself on its own /v1/models — the gateway was flattening a distinction that existed one layer down. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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7b4acd9284 |
A replica missing a shard is not ready
Restarting the control plane over a running two-node replica adopted half of it. Every shard it still had was healthy, so it was reported Ready — with one shard of two and no endpoint at all, because the missing one was rank 0. The router was handed a replica nothing could route to. The cause is that a replica had no idea how many shards it should have. It could tell "every shard I have is ready" and nothing else, which is the same sentence whether or not half of it is gone. It now carries the count from its profile, set at placement and again at adoption, and a replica short of shards fails rather than pretending. Onboarding also wrote no engine paths, so a node onboarded by the script could not find llama-server and failed every shard placed on it with "executable file not found". The script now takes them, and says so when none are given — a node with no engine paths can run the sim engine and nothing else. The cluster now runs both at once: two-node simulated replicas on each fabric, and real llama.cpp inference on the CPU, which is a better test bed than either alone. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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c1ac2f022f |
Onboard a node with a script, and find two examples that never worked
New nodes had been joined by hand, four times, by me. There was no procedure, so there was nothing to be wrong — and nothing to be right either. Two scripts now: provision-node.sh makes the VM on Proxmox, onboard-node.sh gives it an identity. They are separate because they are run by different people with different access, and the second must run where the certificate authority is, which is the one part that cannot be delegated. Running them turned up why phase 4 was never verified. FabricAttachment carried no koanf tags, so the `name:` key the shipped example documents bound to nothing and `rate_gbps` was never read at all. An agent configured exactly as instructed refused to start with "fabrics[0]: name is required" — naming the key the operator had just written. Every fabric in this project had been configured in a Go test, where the tags do not matter. The server example did not load either: its models had no source, so it failed validation the moment anything tried to parse it. Both examples are now parsed by a test. A published example that has never been loaded is a guess, and these two had been guesses since they were written. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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058ee382fa |
An agent reporting nothing is reporting something
The previous commit taught the reconciler to let go of shards an agent says it is not running. It made no difference on the cluster, because the service returned early when the agent's list was empty — which is precisely the case that carries the news. So the fix was dead code in production while its unit tests passed, and they passed because they called the reconciler directly. The test added here goes through the real stream instead, and asserts only that an agent running nothing reaches the reconciler at all. That is the lesson worth keeping: a test that calls the function under test directly cannot tell you the caller never calls it. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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aef1c143c5 |
Let go of shards an agent says it is not running
Adoption handled "the agent has something we do not know about". The mirror image was missing: "we think the agent has something it does not". Both follow from the same rule — the fleet is authoritative about what is running (plan §6.5) — and without the second half an engine that dies while its agent survives leaves the control plane believing a replica is Ready forever. Measured on the cluster: the engine was killed, the agent restarted and registered with nothing running, and the replica stayed Ready pointing at a dead port for two and a half minutes until I stopped watching. Traffic survived, because the breaker took the endpoint out and retries covered it — 24 requests, none failed — so the only symptom was a cluster quietly running a third short. A registration follows a fresh connection, so anything dispatched over a previous one is not running by definition; there is no window where a shard is legitimately started but unreported. The previous commit's disown rule was too broad, which this turned up: when a known replica had a live shard it disowned everything the agent reported for it, including the shards we already knew. A reconnecting agent would have been told to stop the replica that was serving. It now disowns only what it does not recognise. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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5c837c531b |
Pin down where CPU replicas land, and where they deliberately do not
Two tests for behaviour that looked wrong on the cluster and was not. Three replicas all landed on one node, which is correct when it is the only node registered: spreading is a preference and a model left unplaced to preserve a preference would be worse. Over successive ticks with somewhere to go, they spread. What neither test asserts, because it is not true: nothing rebalances them afterwards. A replica that moved on its own would interrupt the traffic it is serving, and v1 has no autoscaler to decide it is worth it. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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8a062fec35 |
Stop reusing replica ids, and stop handing out ports strays still hold
The previous commit's adoption fix made a deeper problem visible instead of
fixing it. Replica ids were the model name and a counter, and the counter
restarted with the process — so a control plane that came back placed a
replica called llama-1 while an engine started before the restart, still
running on a different node, also called itself llama-1.
Two nodes then claimed the same shard id. Adoption handed it back and forth
between them, every placement landed on a port an orphan was still bound to,
and the engine failed to bind, which failed the replica, which placed another
one on the same port. On the real cluster that loop ran for minutes:
couldn't bind HTTP server socket, hostname: 0.0.0.0, port: 20002
Ids now carry four random bytes, which costs nothing and makes the collision
impossible. The "already known" branch in adoption goes back to meaning what
it says: an agent reconnecting, not a name clash across restarts.
Ports a stray still holds are also reserved now. Stopping is not instant and
an engine keeps its socket until it exits, so the allocator has to know about
sockets no replica claims — otherwise the same loop reappears in the window
between telling an agent to stop something and it actually stopping.
Two of the tests written for the previous commit had quietly become vacuous
under the new ids, asserting things about a literal llama-1 that no longer
exists. They capture the id now.
Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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Ilker ManapandClaude Opus 5
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05bdc7d6d4 |
Add ctl bench, and fix two holes it walked into
`ctl bench` measures what a replica can actually serve, so weight, target_waiting and kv_ceiling stop being numbers somebody typed. Concurrency climbs until the SLO breaks and the last level that met it is the capacity: peak throughput arrives long after latency has become unusable, so throughput alone overstates what the hardware can serve. Queue depth and KV usage are read from the engine while it is still meeting the target, which is exactly what admission should treat as healthy. Prompts are unique per request by default. With one repeated prompt the engine's cache answers most of the prefill and the measurement describes the cache rather than the hardware; --shared-prefix asks that question deliberately, and it now produces byte-identical prompts, which the first version did not — it dropped the random header and still picked words at random, so the cache missed and the flag quietly measured the thing it exists to avoid. Running it against the cluster turned up two real defects: A replica stuck in Starting never timed out. Every other way out of that state needs the agent to report something, and when it never does the replica sits there holding GPUs and counting towards the model's replica count while serving nothing. Two of them had been like that for eight minutes past a two-minute startup timeout, and nothing would ever have moved them. They were stuck because adoption lost to a replica we had only placed. Replica ids come from the model name and a counter, so a control plane that restarts and places before its agents reconnect builds a different replica under the same id on a freshly allocated port; the agent's report of the engine that was actually serving was then discarded as already-known. The cluster pointed at port 20004 while the engine answered on 20000. The fleet is authoritative about what is running, so what we merely placed now loses to what an agent reports — unless our copy has a shard that has actually come up, in which case two things really are running and the stray is the one we did not ask for. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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1839832b8b |
Add a landing page and a read-only cluster dashboard
Pasting the gateway's address into a browser returned 404, which looks like a broken endpoint rather than one that tells you how to use it. Two pages, and the split between them is a security boundary rather than a layout choice. The landing page is served without a key — it has to be, because the person reading it is the one who does not have one yet — so it contains no data at all: it says how to connect, not what is here. Model names stay behind /v1/models. It reconstructs the address from the forwarded headers so the copy-pasteable example names the address the client actually used rather than the internal one; those headers are reflected into displayed text and never used for a decision. The dashboard shows nodes, models, replicas, placement failures and usage, and lives on the admin listener only. That listener is loopback-bound and also serves pprof, which can dump the process heap — where API keys sit in plaintext — so reaching the page from elsewhere is an SSH tunnel's job. It is read-only: anything that mints a credential stays in `llmgw keys`, where it needs a shell rather than a browser session this project has no way to authenticate. Mounting the landing page uncovered a hole in the exemption list. An entry ending in "/" was a prefix rule, and "/" ends in "/", so exempting the landing page would have exempted every path there is — authentication still installed, still logging, and letting the whole API through. "/" is now exact, with a test enumerating what must and must not be exempt. Server-rendered templates and one stylesheet, embedded. The single-binary goal rules out a JavaScript toolchain and nothing on either page needs one. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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501db3d3e8 |
Add the llama.cpp engine, and let a profile ask for no GPU
llama.cpp is what makes a cluster with no cards useful: it serves the same OpenAI API on CPU, so the whole path — placement, supervision, scraping, scheduling, admission — can be exercised end to end on ordinary machines. Three things had to give way for it. A profile may now omit its GPU class, and that is how it says it runs on the CPU. Only engines that can actually serve without a card may omit it; for vLLM an omitted class stays an error, because otherwise a typo becomes a replica placed on a machine with no hardware and diagnosed minutes later during model loading. Placement spreads CPU replicas instead of bin packing them, since unlike GPUs there is no allocation to stop two of them sharing a machine's cores. Metric mappings are now per engine rather than per cluster. llama.cpp calls the same three numbers requests_processing, requests_deferred and kv_cache_usage_ratio, and a single global mapping would leave half a mixed fleet unmeasurable. An empty mapping still defaults to vLLM's names; one that names its own Running metric is taken as a complete statement, so the fields it leaves blank stay blank rather than being filled with names that engine cannot have. The adapter refuses multi-node and tensor-parallel profiles. llama.cpp splits across local GPUs by a different mechanism than this adapter drives, and accepting either would produce a replica that starts and then serves from one machine while the catalog believes it has several. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5
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1e3cafdc86 |
Add a private CA and mutual TLS for the agent stream
A node's identity was whatever the agent said it was. With mutual TLS the control plane compares the client certificate's common name against the claimed node id and refuses the connection when they disagree, so identity becomes something a node proves rather than something it picks. A public authority cannot supply these certificates: Let's Encrypt and its peers stopped issuing the clientAuth usage, and Go verifies client chains against it. Hence internal/tlsconf/ca.go, a small authority whose key lives on one machine and whose root is trusted everywhere, and `llmgw ctl cert` over it so issuing is reproducible instead of remembered openssl. The server certificate's hosts matter more than they look: hostname verification reads subject alternative names and ignores the common name entirely, so a certificate without the address agents dial — bare IP included — is rejected no matter what its subject says. There is a test for exactly that, because it is the failure everyone hits once. requireIdentity stays wired to false until the configuration lands, so this commit changes no running behaviour. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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 ilkerandClaude Opus 5
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e1eb1d4149 |
Phase 3: ctl, and make draining a rolling move
ctl talks to a management API on the admin listener, not the client-facing one. The two have different audiences: one serves inference to whoever holds an API key, the other lets a caller cordon nodes and read the cluster's shape. - nodes surfaces unhealthy GPUs and why they are excluded. That is usually the answer when a node looks idle but nothing will schedule onto it, and it was invisible before. - explain-placement prints every candidate considered and why it was rejected. - replicas shows the shards a replica is made of, with per-shard errors. - cordon, uncordon and drain are one endpoint with different targets, because the difference between cordon and drain is exactly what an operator needs to be sure of before running either. Draining had to be fixed first to make ctl drain worth having. A drained replica was stopped on the next pass, which cuts in-flight requests — the thing draining exists to avoid. Now a node marked Draining has its replicas drained, the model falls below its desired count, a replacement is placed elsewhere, and the original is stopped only once the replacement is serving. A grace period bounds it, because draining the only node that can host a model would otherwise never finish and the node could never be taken out of service. Verified against a two-node cluster of real binaries: draining moved a replica to the surviving node and traffic kept returning 200 throughout. ctl logs is deliberately absent. It needs a request/response pair the agent protocol does not have, and the failure path already ships an engine log tail with every status report — so the case that matters most is covered, and reading a healthy shard's output on demand is not worth a protocol change yet. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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1d1a6aebb0 |
Phase 4: make a multi-node replica able to start
Placement and environment generation had landed early, which made multi-node look further along than it was. A replica spanning nodes could not come up at all, and all three reasons came down to assumptions that only hold on one node. Not every rank serves HTTP. The agent health-checked every shard at its own port, but only the leader answers; workers timed out, reported Failed and took the replica with them. Engine.ServesHTTP now says which ranks serve, and a worker is judged by staying alive. That is deliberately weaker evidence: the replica's real readiness is the leader answering, which only happens once every worker has joined. A shard is not always one process. Engine.Commands returns a sequence — every command but the last is a sidecar kept alive for the shard's lifetime and torn down with it, and the last one's exit is the shard's. vLLM under Ray is why: the leader runs a Ray head and then the server against it, while a worker runs only the join and no vLLM process at all. RayCommand had been written and tested but never called, so launch_mode: ray would have run vllm serve against a cluster that did not exist. Sidecars are killed with the shard, because a Ray head left behind holds the port the next replica needs. Start order was backwards. Workers went first, on the theory that the head should wait for them. Both engines put the rendezvous point on rank 0, so a worker started first has nothing to connect to. vLLM's server blocks until the Ray cluster has the GPUs it needs, so the leader can start immediately and waits on its own. A command can now also require that rendezvous point to be listening before the next starts, bounded by a timeout so a head that never appears fails the shard instead of hanging it. Stop was also killing only the engine, leaving sidecars behind. None of this is verified against real engines — it is tested with stub processes. The Ray sequencing, and which launch mode a given vLLM version wants, can only be confirmed on hardware. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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75a8e76706 |
Survive a control plane restart without orphaning live engines
Not persisting replica state left one hole: restarting the control plane made it forget every replica while the engines kept running. They held GPUs the inventory believed were free, so the next placement failed to allocate, with an error naming the new process rather than the old one. The fix belongs on the agent, not in a database. A row can say "running" about a process that died; the fleet cannot. - the supervisor writes the full shard spec, not just a pid and command line. A pid identifies a process; the spec is what lets it be described back to the control plane and matched to a replica. - Adopt takes over an engine a previous agent left running. It is not this process's child, so it cannot be waited on: it is watched by polling and stopped by signalling its group directly. Its earlier output is gone and the log says so rather than presenting emptiness as silence. - every Register reports what the agent is running, not only the first, because a reconnect may be a control plane restart and has to recover the same way. - the reconciler rebuilds replicas from those reports and reclaims their GPUs. Anything whose model or profile left the catalog is stopped; nothing will route to it and it is holding cards. - an engine the agent cannot identify is killed. A process holding GPUs that nothing can describe is worse than no process, because placement hands those GPUs out again. Stop was also wrong for adopted shards: it checked for an exec.Cmd, which they do not have, and reported them stopped without killing anything. TestAgentReconnects had been passing for no reason. httptest's CloseClientConnections does nothing to an h2c stream — prior-knowledge h2c hijacks the connection and httptest stops tracking hijacked ones — so the agent never reconnected, and the assertion on the connection map passed on a stale entry. Tests now sever connections through their own listener and count opened streams. Plan §11 also records what multi-node still needs, since placement landing early makes it look further along than it is: workers never become Ready because the agent health-checks every shard while only rank 0 serves HTTP; RayCommand is written and tested but never called; and startup is fire-and-forget. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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2373726efd |
Agent stream: connect the fleet to the control plane
One bidirectional connect-go stream per node, carrying registration, heartbeats and shard status up, and start, stop and drain down. The agent dials out: GPU nodes sit behind firewalls far more often than a control plane does, and an outbound connection needs no inbound rule on every node in the fleet. - registration carries the whole hardware inventory, so there is no separate discovery call and a reconnecting agent refreshes what the scheduler knows. The fabric labels travel with it; they cannot be inferred from the wire, so losing them in transit would silently disable multi-node placement. - agentsvc is both the stream handler and the reconciler's dispatcher, because it holds the open streams and is therefore the only thing that can deliver a command to a node. - the agent validates a profile before launching anything, since an engine that refuses a profile does so after minutes of loading, then supervises the process and reports every transition with the engine's output tail on failure. - reconnects forever with jittered backoff. A control plane restart must not require touching every GPU node, and a fleet must not reconnect in lockstep and knock it over again. Engines keep serving throughout, because the router talks to them directly. llmgw agent is real now, and llmgw server runs a control plane whenever any model declares a profile. The static endpoint list stays for router-only runs. Verified with real binaries as separate processes: the agent registers, a replica is placed, an engine launches through the vLLM adapter's actual argument construction, streaming traffic is served, and killing the agent moves the node through unreachable to lost with placement explaining why nothing can run. config.Model and catalog.Model were the same thing described twice, so the router now reads catalog entries directly and the validation rules live in one place. Still missing: mTLS. The stream is plaintext HTTP/2 and must stay on a trusted network until that lands. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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c1b9ea1bc2 |
Phase 3 (3/3): wire the control plane to the router
Ready replicas become router endpoints with no static configuration involved. Endpoints that survive an update keep their live state — inflight counts, breaker state, drain rate — so a replica that was already serving does not start from cold because another one moved. The sink is an interface, so when the router and control plane split into separate processes it becomes a watch stream and nothing above it changes. Phase 3's exit criterion now holds end to end. A node hosting a live replica is killed while four clients stream continuously; the control plane marks it unreachable, then lost, rebuilds the replica on a survivor and republishes. Across three runs ~370 requests completed with zero failures and no replica was left on the dead node. This proves the control logic, not the transport: the agent fleet is simulated and the real path still needs the stream. The race detector caught a genuine bug while this went in. startReplica read the replica's fields after publishing it to the map, and scaleUp walked replica pointers outside the lock; both raced with agent status reports, which arrive from another goroutine and mutate exactly those fields. Against the simulated fleet the reports came back fast enough to hit the window on every run. State is snapshotted under the lock now and those functions work from values. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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f0134a2f95 |
Phase 3 (2/3): catalog and reconciler
The desired-versus-actual loop, with a Dispatcher interface where the agent stream will go. The loop's logic is where the interesting failures live, not the transport, so it is tested against a fake dispatcher and a synthetic clock. - catalog: models, profiles, aliases, fallbacks, scaling bounds. Aliases and fallbacks resolve at load rather than at request time, because a typo in a fallback should stop a deployment instead of surfacing during the outage when the fallback is finally needed. The node/GPU/TP arithmetic is checked here too, so a bad profile fails at config load rather than minutes into loading. - reconciler: one replica placed per pass, since placement depends on what is already allocated and several from one snapshot would be handed the same GPUs. Workers start before rank 0: SGLang's ranks rendezvous and vLLM under Ray needs its workers attached before the head serves. - a failed shard fails the whole replica. The others are waiting on collectives that will never complete while holding GPUs, so every shard is stopped and the replica rebuilt, with a jittered exponential backoff carried on the model rather than on the replica that was just destroyed. - node expiry has two stages, Unreachable then Lost, deliberately far apart: a network blip must not tear down replicas that are still serving, and rebuilding a multi-node replica costs tens of minutes of model loading. - scale-down drains before stopping, so in-flight requests finish. The phase 3 exit criterion is half met. TestLostNodeMovesReplicas covers the reconciliation half end to end. The router continuing to serve throughout needs the EndpointSource wiring and the agent stream. Writing the tests caught a real property of the design worth recording: advancing the clock makes every node look silent, so placement correctly stops. The test harness now heartbeats nodes as it advances time, except where a node going silent is the point. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |
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ilkerandClaude Opus 5
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06672d1b85 |
Phase 3 (1/3): cluster inventory and placement
The two hard constraints from plan §1.1 are enforced structurally rather than checked after the fact: there is no code path that can combine nodes from two fabrics, and only GPUs of the profile's class are ever considered. Getting either wrong produces a replica that starts, passes health checks, and then hangs or crawls under load — which looks like success until traffic arrives. - inventory: nodes, hardware, fabric attachments, allocations. A re-registering agent cannot clear an operator's cordon, since a cordon is usually in place because something is wrong with the node. A GPU with an ECC fault or another process on it is not free in any useful sense. Replicas are released whole, because they fail whole. - placement: highest-priority profile that fits, with every rejected candidate explained. "Unschedulable" on its own tells an operator nothing about which of six constraints bit. - bin packing fills partly used nodes first so whole nodes stay free for large models that cannot be split; multi-node replicas get the emptiest machines instead, being the least movable thing in the cluster. - NVLink-aware GPU selection keeps a tensor-parallel group inside one domain where the topology is known, falling back to lowest free indices otherwise. Property-based tests generate 400 random clusters and assert the invariants on every placement produced: one fabric per multi-node replica, only that fabric's HCAs per shard, one GPU class, no unhealthy or already-allocated GPU. The table-driven tests cover the cases someone thought of; these cover the rest. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com> |