bf2d171e8941bbff7cbbfba078a5ceb18c388f9e
9
Commits
| Author | SHA1 | Message | Date | |
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 Ilker ManapandClaude Opus 5.5
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daed835d88 |
Measure each node's CPU and memory, and give every node a page
The nodes are CPU machines, and nothing measured how busy one was: the heartbeat carried GPU memory and disk, and llmgw_node_memory_bytes is the total. The agent now reads /proc between heartbeats - CPU across all cores, load averages, memory used and available, and each engine's process group's cores and resident memory - and sends it with the heartbeat. Nothing new runs on the nodes and Prometheus needs no new target: the control plane exports it with the rest of the fleet, as llmgw_node_cpu_utilization_percent, llmgw_node_cpus, llmgw_node_load, llmgw_node_memory_used_bytes, llmgw_node_memory_available_bytes, llmgw_shard_cpu_cores and llmgw_shard_memory_bytes. A measurement more than a minute old is left out rather than repeated. The cluster page's node table shows CPU and RAM as bars, and each node links to a page of its own: current CPU, RAM, load and disk, the engines on it with their cores and memory, and an hour of CPU, RAM, load, per-model cores and memory and queue depth from Prometheus. It refreshes in place. Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com> |
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Ilker ManapandClaude Opus 5.5
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7d97c6b74f |
Install a node's engines on the node, instead of trusting what is there
A node ran whatever llama-server somebody had once unpacked on it. Onboarding checked an engine only when told its path, installed none, and a node with nothing on it registered as ready. The one time that went wrong it went wrong invisibly: the binary was there, executable, and could not start for want of libgomp1, while the node reported healthy. The control plane now says which engines every node has, at which version — `engines:` in server.yaml, defaulting to the llama.cpp build this release was checked against — and each agent converges on it. What only the node can know, the node works out: the build for its processor and driver (CUDA with its runtime when an NVIDIA driver is loaded, CPU otherwise), the OS packages that build needs from its own package sources, and whether the result runs. Every archive is checked against the sha256 GitHub publishes for it and unpacked refusing any path or link that leaves the install directory. ldd names a missing library outright; running `--version` proves the rest. Only then is a directory marked installed, and it is checked again every ten minutes, because an unrelated upgrade can remove a library. An engine is reported only once installed and seen to run, or when the agent's configuration names it on purpose — never because something happened to be on PATH. The agent now says when it has probed, so an empty list means "has none" rather than "too old to say": a node rebuilt from nothing is no longer a candidate for every model at the moment it can run none of them. Placement's refusal carries the node's own words, "installing: downloading llama-b10991-bin-ubuntu-x64.tar.gz (16 MB)", and so do `ctl nodes` and the cluster page, along with a warning for a CPU without AVX2 — the VM CPU type that makes everything five times slower and nothing look wrong. Agents also report their OS, architecture, vector extensions and NVIDIA driver. Onboarding installs llmgw itself from the CI release for the node's architecture, checked against the release's checksums, rather than copying whatever binary the operator's machine had. vLLM and SGLang are not installed yet: they are Python environments of several gigabytes, not an archive, and still have to be named in the agent's configuration. Also fixes a race on the weights fingerprint, which two heartbeat loops touch during a failover. Co-Authored-By: Claude Opus 5.5 (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
CI / test (push) Successful in 1m46s
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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753f4e3265 |
Let a node say how much room it has left
CI / test (push) Failing after 1m31s
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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c13c567cc5 |
Know where the weights are, without owning the storage
CI / test (push) Successful in 1m32s
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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3081c6f69b |
Place on nodes that can actually hold the model
CI / test (push) Successful in 1m23s
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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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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 ilkerandClaude Opus 5
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f0134a2f95 |
Phase 3 (2/3): catalog and reconciler
CI / test (push) Successful in 24s
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
CI / test (push) Successful in 23s
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> |