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test(fault_tolerance): share a SIGTERM-only graceful shutdown context - #14279
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The graceful_shutdown arm of the request-migration tests asserted that a SIGTERM'd worker migrates its in-flight request. That contradicts Dynamo's documented graceful-shutdown contract: a worker that receives SIGTERM stops accepting new work and drains the requests it has already admitted, so no migration should occur at all. The tests only saw a migration because run_migration_test's default non-immediate-kill path calls terminate_process_tree with timeout=2, which escalates to SIGKILL two seconds after SIGTERM and cuts the drain short. That is a delayed worker failure, not a graceful shutdown. - utils.py: promote the SIGTERM-only shutdown context (previously private to test_sglang.py) to a public, backend-agnostic graceful_worker_shutdown helper, parameterized by the (component, endpoint) pair the faulted worker registers so prefill workers can be drained too. - utils.py: add an opt-in expect_drain flag to run_migration_test. It requires the request to succeed regardless of migration settings and pins every migration counter to exactly zero (exact_counts=True), because a lower-bound check against zero asserts nothing. - test_vllm.py, test_trtllm.py: drive the graceful_shutdown arm through the shared context with expect_drain, replacing the unconditional expected_ongoing_request_count=1 in the vLLM tests. The worker_failure arm is unchanged. test_sglang.py is deliberately untouched; its collected parametrization ids are byte-identical before and after this change. Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
…ract The expect_drain branch pinned expected_max_seq_len_exceeded_count to 0, but that counter is driven by ordinary token accounting in RetryManager::exceed_max_seq_len, not by a worker fault. It fires once at request build time whenever the prompt already exceeds the configured migration seq-len cap, so rows with migration_max_seq_len=1 record one event even when the worker drains perfectly. Share the existing expression with the non-drain path so both arms expect the same seq-cap value, and document why that counter is not part of the drain contract. Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
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Automated evidence record — validation incompleteValidation status: incomplete Evidence summary: [4/5 validated · 1 needs hardware] AI review assessment (advisory, not an approval): Validation result: incomplete — the recorded run evidence shows validation did not pass. Four of the five recorded checks passed; the fifth, which runs the GPU-dependent migration tests, failed because the GPU driver on the machine used reports CUDA 12.8 while the installed PyTorch 2.11.0 and vLLM 0.26.0 are built for CUDA 13.0, so no worker engine starts. The graceful-shutdown drain behaviour this change asserts therefore remains unobserved. Evidence audit: complete [4/5 validated · 1 needs hardware] — the command report below comes from recorded runs. Commands and results [4/5 validated · 1 needs hardware]Generated from the commands recorded during this run. Check 1Builds the changed Dynamo source and confirms that Python can import its compiled extension. Result: Passed ( Command: Not shown because the exact command contained private run data. Check 2Checks the changed files with the repository's fast lint and formatting commands. Result: Passed ( Command: Not shown because the exact command contained private run data. Check 3Runs the relevant Python unit tests without requiring a GPU. Result: Passed ( Command: Not shown because the exact command contained private run data. Check 4Inspects the changed code when the claim cannot be tested with a local command. Result: Passed ( Command: Not shown because the exact command contained private run data. Check 5Runs the relevant GPU-dependent Python tests against the changed source. Result: Failed ( Command: Not shown because the exact command contained private run data. Details: The two graceful-shutdown migration tests were attempted on this machine and both failed before any inference happened: the host GPU driver reports CUDA 12.8 while the installed PyTorch 2.11.0 and vLLM 0.26.0 are built for CUDA 13.0, so CUDA initialisation raises "The NVIDIA driver on your system is too old (found version 12080)" and neither vLLM worker engine starts. |
review.md
Assessment: needs_changesThe change makes the fault-tolerance migration suite assert a drain contract on the One of the two blocking findings from the previous pass is now genuinely fixed. The other 1. The sequence-length counter defect is fixed — and the earlier reasoning about it was wrong
expected_max_seq_len_exceeded_count = 1 if migration_max_seq_len == 1 else 0That is correct, and it is correct for more rows than the previous review believed. The previous review claimed rows with
So with This finding is resolved. It is not carried forward. 2. Blocking: the drain contract is asserted as an exact zero, is unobserved, and the repository asserts the opposite
if expect_drain:
verify_migration_metrics(
frontend.frontend_port,
expected_ongoing_request_count=0,
expected_new_request_count=0,
expected_max_seq_len_exceeded_count=expected_max_seq_len_exceeded_count,
exact_counts=True,
)
return
(a) The suite already asserts the opposite from the same shutdown shape. Both cannot be describing the same runtime behavior. Either the two backends genuinely (b) The runtime routes a shutdown error to the migration layer, on purpose. (c) The behavior was never observed. The change's own validation report reaches To be fair about what was established: the harness was driven directly with the request Separately, the new What would settle this: one run of the vLLM aggregated graceful-shutdown rows on a host I would also expect the change to say, in the same breath, why SGLang's expectation of 1 What the change does engage with honestlyThe change description does not hide any of this. It names the SGLang counter-evidence Non-blocking notesAn absent metric series reads as zero. The SGLang helper is now a stale duplicate. Test-quality checkThe diff adds no new test cases — collection is identical at 412 before and after — so |
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No actionable comments were generated in the recent review. 🎉 ℹ️ Recent review info⚙️ Run configurationConfiguration used: Path: .coderabbit.yaml Review profile: CHILL Plan: Enterprise Run ID: 📒 Files selected for processing (4)
Included review availability: Your plan provides up to 12 included reviews per hour; 9 remain after this review. WalkthroughMigration tests now share a frontend-aware graceful worker shutdown utility. The utility drains the backend after SIGTERM, validates request handling, and then force-kills captured process groups. SGLang’s local implementation was removed. ChangesMigration shutdown handling
Priority: ⬇️ Low Estimated code review effort: 2 (Simple) | ~10 minutes Merge Risk: ⚪ Minimal · up to The shared shutdown test utility preserves the existing migration validation flow without an established merge-blocking regression. 🚥 Pre-merge checks | ✅ 5✅ Passed checks (5 passed)
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In `@tests/fault_tolerance/migration/utils.py`:
- Around line 508-511: Update the process-group inspection exception handling
around the visible cleanup logic to catch only ProcessLookupError, allowing
OSError and psutil.AccessDenied inspection failures to propagate before SIGTERM
so live child groups cannot be omitted from process_groups.
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tests/fault_tolerance/migration/test_trtllm.pytests/fault_tolerance/migration/test_vllm.pytests/fault_tolerance/migration/utils.py
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Keep the graceful-drain contract on the TRT-LLM aggregated and decode tests, which run in CI, and leave the unconditionally skipped prefill and KV-transfer tests unchanged so no unexercised assertion ships. With no prefill caller left, graceful_worker_shutdown resolves the worker endpoint from a module constant instead of an unused parameter, and it suppresses only the disappearing-process errors so a permission failure cannot silently drop a live child process group. Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
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/devin review @coderabbitai full review |
🧩 Analysis chain🏁 Script executed: #!/bin/bash
set -euo pipefail
echo '=== PR metadata ==='
gh pr view 14279 --repo ai-dynamo/dynamo --json baseRefName,headRefName,headRefOid,files --jq '{base: .baseRefName, head: .headRefName, oid: .headRefOid, files: [.files[].path]}'
echo '=== Changed-file diff ==='
git diff --find-renames origin/main...HEAD -- \
tests/fault_tolerance/migration/utils.py \
tests/fault_tolerance/migration/test_vllm.py \
tests/fault_tolerance/migration/test_trtllm.py \
tests/fault_tolerance/migration/test_sglang.py
echo '=== Outline: migration utilities ==='
ast-grep outline tests/fault_tolerance/migration/utils.py --items all --type function --match 'graceful_worker_shutdown|run_migration_test|verify_migration_metrics|_parse_migration'
echo '=== Outline: backend tests ==='
ast-grep outline tests/fault_tolerance/migration/test_vllm.py --items all --type function
ast-grep outline tests/fault_tolerance/migration/test_trtllm.py --items all --type function
ast-grep outline tests/fault_tolerance/migration/test_sglang.py --items all --type functionLength of output: 14320 🏁 Script executed: #!/bin/bash
set -euo pipefail
echo '=== Utility declarations and lifecycle ==='
sed -n '400,510p' tests/fault_tolerance/migration/utils.py
sed -n '620,745p' tests/fault_tolerance/migration/utils.py
sed -n '775,985p' tests/fault_tolerance/migration/utils.py
echo '=== ManagedProcess definition and termination semantics ==='
rg -n -A90 -B15 'class ManagedProcess\b|def terminate_process_tree\b|def get_pid\b|def terminate\b' tests
echo '=== vLLM migration parameterization and calls ==='
sed -n '385,670p' tests/fault_tolerance/migration/test_vllm.py
echo '=== TensorRT-LLM migration parameterization and calls ==='
sed -n '190,500p' tests/fault_tolerance/migration/test_trtllm.py
echo '=== Existing SGLang graceful shutdown contract ==='
sed -n '35,90p' tests/fault_tolerance/migration/test_sglang.py
sed -n '480,800p' tests/fault_tolerance/migration/test_sglang.py
echo '=== All run_migration_test call shapes ==='
rg -n -A20 -B8 '\brun_migration_test\s*\(' tests/fault_tolerance/migrationLength of output: 136959 🏁 Script executed: #!/bin/bash
set -euo pipefail
echo '=== Exact shutdown helper ==='
sed -n '470,540p' tests/fault_tolerance/migration/utils.py
echo '=== ManagedProcess launch and cleanup ==='
sed -n '220,390p' tests/utils/managed_process.py
sed -n '760,885p' tests/utils/managed_process.py
echo '=== psutil dependency declarations ==='
rg -n -C2 '(^|["'\''])psutil([<=>!~\[]|["'\'']|$)' \
pyproject.toml uv.lock requirements.txt requirements*.txt setup.py setup.cfg \
2>/dev/null || true
echo '=== Current PR commits ==='
git log --format='%h %s' origin/main..HEAD
echo '=== Static syntax check of changed Python sources ==='
python - <<'PY'
import ast
for path in (
"tests/fault_tolerance/migration/utils.py",
"tests/fault_tolerance/migration/test_vllm.py",
"tests/fault_tolerance/migration/test_trtllm.py",
):
with open(path, encoding="utf-8") as source:
ast.parse(source.read(), filename=path)
print(f"AST parse passed: {path}")
PYLength of output: 16304
I found no new actionable defects in the current diff. The shared graceful shutdown path has consistent control flow. It sends The drain assertions apply only to runnable vLLM and TensorRT-LLM tests. The skipped TensorRT-LLM prefill and KV-transfer tests remain unchanged. Static AST parsing passed for all changed Python files. The graceful-shutdown runtime behavior remains unverified because the available GPU environment has an incompatible CUDA driver and installed PyTorch/vLLM builds. ✅ Action performedFull review finished. |
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@glamr-agent thanks for proposing this fix!
based on the above root cause you found, can you explain briefly on how you fixed the issue? why don't we simply increase the timeout at |
…kends _sglang_graceful_shutdown duplicated graceful_worker_shutdown line for line: same /health baseline, same process-group capture, same SIGTERM then wait-for-discovery-removal, same SIGKILL by process group in a finally. Import the shared helper from .utils and drop the local copy so the three backend suites share one implementation. The shared helper lets an inspection failure other than a missing process propagate instead of being swallowed, which the local copy suppressed via psutil.AccessDenied and OSError. Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
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@kthui thanks — and the second half of your question is the right one to ask, because raising the timeout does work. How the change fixes it
Two pieces replace that. On simply raising the timeoutIt would pass, and nothing in the assertions needs the context manager. What stopped me is that The context has no such constant: escalation is triggered by the outcome being known rather than by a clock. It is also not new machinery. If you would still rather have the small version, say so and I will cut it back to One thing worth flagging while you are here
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@kthui thanks — you are right that the two timers are separate, and I traced the one you asked about. The short answer is that with the backend grace period at What
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Correction to my previous comment: I said I had no observed result, only the code path. I do now. The question is about the runtime shutdown path rather than about vLLM specifically, so I was able to exercise that leg without a GPU and get an answer. SetupA local NATS and etcd, a worker serving await endpoint.serve_endpoint(handler.generate, graceful_shutdown=gs)whose handler yields 20 tokens at 0.5 s apart and logs which way it ends ( This is the worker-to-caller leg only — no vLLM engine, no HTTP frontend — so it does not exercise the frontend's migration logic. It establishes whether that logic has any error to act on. What happened
No
The error-reporting path is real and fires immediately when the worker is severed, and What it does and does not settleIt settles the mechanism: interrupt the worker and the caller gets a migratable error; let it drain and the stream completes. That is the split the diff encodes, with It does not settle the two questions I left you, and I am not treating it as if it did. Whether the graceful arm should assert a migration is a contract decision, and the |
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@glamr-agent thanks for investigating and running the additional experiment. The intended contract is that, once the backend’s graceful-shutdown period expires, remaining ongoing requests should be interrupted and receive the appropriate error so the frontend can migrate them. Setting the period to Could you trace this through the actual backend shutdown path? Specifically, verify when the request monitor observes grace expiry, when it interrupts generation and reports the shutdown error, and when the frontend receives that error. Please check whether any blocking shutdown work delays that notification, or whether the error is produced but fails to reach the frontend. The generic handler experiment demonstrates runtime draining, but it does not exercise the backend’s shutdown event and request-abort monitor. I suggest preserving the migration expectation while investigating this path; observing a completed stream alone does not establish that the grace-expiry contract was honored. |
… arm The backend does interrupt an admitted request once its graceful-shutdown period expires. `graceful_shutdown_with_discovery` sets the shared `shutdown_event` after the grace sleep and the pre-shutdown callback but before engine cleanup, and each handler's per-request abort monitor is waiting on it: it calls `engine_client.abort(request_id)` and raises `EngineShutdown`, which reaches the frontend as `ErrorType::Backend(BackendError::EngineShutdown)` and is migratable. So a SIGTERM'd worker does not drain its in-flight request, and the drain assertion this branch added was asserting the wrong contract. Drop `expect_drain` and restore the migration expectation on every graceful row, which also makes the vLLM and TRT-LLM suites agree with SGLang instead of contradicting it. `graceful_worker_shutdown` stays. Removing the harness's two-second SIGKILL escalation is what makes these rows meaningful: with it, a severed connection produced the migration, so the row passed without ever exercising the backend's shutdown event, abort monitor or error propagation. With SIGTERM alone, that path is the only thing left that can produce it. Signed-off-by: GLAMR <svc-glamr@nvidia.com> Signed-off-by: svc-glamr@nvidia.com <svc-glamr@nvidia.com>
glamr-agent
changed the title
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@kthui you were right, and my previous answer was wrong. There is a request-abort monitor on the backend path, it does observe grace expiry, and I missed it. Here is the trace you asked for, then what I changed. Why the previous answer was wrongThe generic handler I ran was served through When the monitor observes grace expiry
if shutdown_event is not None:
shutdown_event.set()then
Answering the blocking-work question directly: engine teardown does not delay the notification, because I timed the real function rather than only reading it. With and with a When it interrupts generation and reports the error
if shutdown_task and shutdown_task in done:
raise EngineShutdown("Engine was shut down during generation.")The I drove that code directly, with a stub engine client: One honest caveat on that last line: my stub engine records When the frontend receives it
This is the one leg I could not execute. It needs the compiled What this means for the change, and what I pushedIt means the premise I built this on was wrong. A What I kept is Nothing in Still needs you
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Revision pushed —
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/devin review @coderabbitai full review |
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Tip For best results, initiate chat on the files or code changes. 🧩 Analysis chain🏁 Script executed: #!/bin/bash
set -euo pipefail
echo '=== PR metadata ==='
gh pr view 14279 --repo ai-dynamo/dynamo \
--json baseRefName,headRefName,headRefOid,files \
--jq '{base: .baseRefName, head: .headRefName, oid: .headRefOid, files: [.files[].path]}'
echo '=== Changed-file diff ==='
git diff --find-renames origin/main...HEAD -- \
tests/fault_tolerance/migration/utils.py \
tests/fault_tolerance/migration/test_vllm.py \
tests/fault_tolerance/migration/test_trtllm.py \
tests/fault_tolerance/migration/test_sglang.py
echo '=== Affected symbol outlines ==='
ast-grep outline tests/fault_tolerance/migration/utils.py \
--items all --type function \
--match 'graceful_worker_shutdown|run_migration_test|verify_migration_metrics|_parse_migration'
ast-grep outline tests/fault_tolerance/migration/test_vllm.py --items all --type function
ast-grep outline tests/fault_tolerance/migration/test_trtllm.py --items all --type function
ast-grep outline tests/fault_tolerance/migration/test_sglang.py --items all --type function
echo '=== Shared helper and migration validation ==='
sed -n '430,540p' tests/fault_tolerance/migration/utils.py
sed -n '640,745p' tests/fault_tolerance/migration/utils.py
sed -n '770,985p' tests/fault_tolerance/migration/utils.py
echo '=== Backend migration test call sites ==='
rg -n -A32 -B10 '\brun_migration_test\s*\(' \
tests/fault_tolerance/migration/test_vllm.py \
tests/fault_tolerance/migration/test_trtllm.py \
tests/fault_tolerance/migration/test_sglang.py
echo '=== Shared shutdown helper usage and imports ==='
rg -n -A10 -B10 '\bgraceful_worker_shutdown\b|\bgraceful_shutdown\s*=' \
tests/fault_tolerance/migration/test_vllm.py \
tests/fault_tolerance/migration/test_trtllm.py \
tests/fault_tolerance/migration/test_sglang.py
echo '=== Managed process APIs referenced by the helper ==='
fd -a '^managed_process\.py$' tests -x sh -c \
'echo "=== $1 ==="; rg -n -A115 -B15 "class ManagedProcess\b|def terminate_process_tree\b|def terminate\b|def get_pid\b" "$1"' sh {}Length of output: 96892 🏁 Script executed: #!/bin/bash
set -euo pipefail
echo '=== Diff whitespace check ==='
git diff --check origin/main...HEAD
echo '=== Complete metric validation and shutdown runner ==='
sed -n '700,795p' tests/fault_tolerance/migration/utils.py
sed -n '850,990p' tests/fault_tolerance/migration/utils.py
echo '=== Structural locations of shutdown context construction ==='
ast-grep run \
--pattern 'graceful_shutdown=lambda $WORKER: graceful_worker_shutdown($FRONTEND, $WORKER)' \
--lang python \
tests/fault_tolerance/migration
echo '=== All direct shared-helper references ==='
rg -n -A3 -B3 '\bgraceful_worker_shutdown\b' tests/fault_tolerance/migration
echo '=== Endpoint constants and discovery-reduction callers ==='
rg -n -A5 -B5 '\bBACKEND_ENDPOINT\b|\bwait_for_endpoint_instance_reduction\s*\(' \
tests/fault_tolerance/migration
echo '=== Imports relevant to removed SGLang helper ==='
sed -n '1,40p' tests/fault_tolerance/migration/test_sglang.py
sed -n '1,42p' tests/fault_tolerance/migration/utils.py
echo '=== Current changed paths and commits ==='
git diff --name-only origin/main...HEAD
git log --oneline origin/main..HEADLength of output: 9188
I found no new actionable defects. The revision preserves the migration expectation for graceful shutdown. Each changed runnable test passes
The skipped TensorRT-LLM prefill and KV-transfer tests remain unchanged.
You are interacting with an AI system. |
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@glamr-agent thanks for tracing the abort monitor and restoring the migration expectations. That addresses the concern about the test contract. The remaining verification is whether the appropriate request error actually reaches the frontend after grace expiry. The stub-engine check demonstrates the abort call and Python exception, but does not establish real engine interruption, timely error delivery, or frontend migration. Since DYN-4268 concerns TRT-LLM, could you focus the next verification on a real TRT-LLM worker and frontend? Please correlate one request across grace expiry, backend abort, the responses/errors emitted, the error received by the frontend, and the resulting migration or expected API error. This should also establish that the request was still generating when grace expired. That trace should determine whether production changes are needed in the TRT-LLM Python backend or the downstream error-handling path. The shared shutdown helper is useful for this investigation, but we should keep the original issue unresolved until the actual failure is understood and verified. Broader vLLM behavior can be investigated separately. |
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@kthui that is the right next step, and I agree the original issue should stay open until it is done. I have to be straight with you about one thing first: I cannot run that verification, so I am handing it over rather than reporting a result. Why I cannot run itThe machine this automation runs on has no TensorRT-LLM at all, and no way to obtain it: It has one A100-SXM4-80GB with vLLM I would rather say that plainly than run a weaker experiment and present it as the trace you asked for. What I got wrong before, and what that means for this branchYou asked twice for the backend abort path and I answered twice from the wrong place — first from the generic runtime drain, then from a stub engine. Both missed that the abort monitor is per-request inside the backend handler. The branch as it stands reflects your correction: the migration expectations are restored, so no test on it now asserts the drain contract I had wrongly inferred. It is test-only and does not claim to fix the defect, which is why leaving the issue open is the right call. The trace, with the anchors I can give youThese are the five correlation points, all reachable from code I could read here:
Two things I could not settle by reading, which I think are where the real answer is:
The To establish the request was still generating at grace expiry, the request needs to outlast the two 30s callback caps, so a long Where that leaves this PRHappy for this to sit until someone with a TRT-LLM machine runs that. If the trace shows a production fix is needed in the TRT-LLM backend or the error-handling path, that is a different change than this one and the harness work here should probably follow it rather than lead it. If it would help to split the shared |
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@kthui I ran the trace you asked for on a real TensorRT-LLM worker and a real frontend. Short answer: the grace-expiry contract is honored on this build — the backend interrupts the ongoing request, raises Setup
One streaming One request across the five pointsEverything below is the same request id, The request was still generating at expiry. The client had received 355 stream chunks when 1 — grace expiry, on the worker. With the period at 2 — the backend interrupts generation, 1.4 ms later: 3 — the error the backend emits. The exception is not swallowed; it unwinds out of the request generator and into the egress path: That is the 4 — the error the frontend receives, 8.0 ms after the abort: 5 — the result is a migration, not an API error: It was re-routed to instance On blocking shutdown workYou asked whether anything delays the notification. Abort at Non-zero grace period, for contrastSame harness with Scope and caveats
Happy to re-run any of this with different parameters, or on |
Signed-off-by: GLAMR <svc-glamr@nvidia.com>
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@coderabbitai full review |
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/devin review |
✅ Action performedFull review finished. |
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@kthui the branch is now merged with current |
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/ok to test 8ba3dee |
Signed-off-by: GLAMR <svc-glamr@nvidia.com>
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@coderabbitai full review |
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/devin review |
✅ Action performedFull review finished. |
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For the reproduced release failures, both the TRT-LLM backend cancellation and the existing tests are correct: when shutdown grace expires, ongoing requests should migrate when permitted or return an error. The root cause is Closing this PR because #14812 addresses the reported release issue. Thanks for the investigation. |
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Overview:
The request-migration fault-tolerance tests run each case twice: an abrupt worker kill (
worker_failure) and a graceful shutdown (graceful_shutdown). Both arms assert that the in-flight request migrates to the surviving worker. On the graceful arm that assertion was not testing what it looked like it was testing. With no caller-supplied shutdown context,run_migration_testtore the worker down withterminate_process_tree(..., timeout=2), which escalates toSIGKILLtwo seconds afterSIGTERM— far shorter than a generation. The severed connection produced the migration by itself, so the row stayed green whether or not the backend's own shutdown path ever reported anything.Details:
tests/fault_tolerance/migration/utils.pygains a sharedgraceful_worker_shutdowncontext. It sendsSIGTERM, waits for the worker to leave frontend discovery, yields while the request outcome is observed, and force-kills the worker's process groups only afterwards, so teardown still cannot leak engine processes that pin GPU memory. Its escalation deadline is the request outcome rather than a constant, so no value has to be guessed to exceed the slowest generation on a loaded nightly runner. Process-group capture suppresses onlyProcessLookupErrorandpsutil.NoSuchProcess, so an inspection failure surfaces rather than silently dropping a live child group beforeSIGKILL.Without the harness
SIGKILL, the only thing that can still migrate the request is the backend's own shutdown path.graceful_shutdown_with_discoverysets the sharedshutdown_eventonce the grace period and the pre-shutdown callback are done; each handler's per-request abort monitor is waiting on that event, aborts the request through the engine client and raisesEngineShutdown; and that reaches the frontend asErrorType::Backend(BackendError::EngineShutdown), whichlib/llm/src/migration.rslists as migratable. The graceful rows keep their migration expectation, and now fail if any link in that chain breaks instead of passing on a dead socket.graceful_worker_shutdownis the only copy of that context for all three backend suites.tests/fault_tolerance/migration/test_sglang.pyimports it at its threegraceful_shutdown=call sites in place of a private duplicate.tests/fault_tolerance/migration/test_vllm.pyadopts it at all three of its call sites and pinsexpected_ongoing_request_count=1, which asksverify_migration_metricsfor an exact count rather than the backend-agnostic lower bound.tests/fault_tolerance/migration/test_trtllm.pyadopts it in the aggregated and decode tests; its prefill and KV-transfer tests carry an unconditional@pytest.mark.skip, so they are left alone rather than given a context no CI stage can exercise. Theworker_failurearm is unchanged everywhere.Where should the reviewer start?
graceful_worker_shutdownintests/fault_tolerance/migration/utils.py, then thegraceful_shutdown=call sites that now use it. The judgement worth making is whether the request outcome is the right escalation deadline for a nightly runner, given that a worker which never reports and never drains would hold the row open until the suite's own@pytest.mark.timeout.Validation
Test-only. No production code changes, and no test function or parametrized argument is added or removed, so the collected node ids are unchanged.
Collection reports
412 tests collected in 0.54swithPYTHONPATHpointing atlib/bindings/python/srcandcomponents/src, which supplies the pure-Pythondynamo.prometheus_namesthattests/utils/payloads.pyimports. Every applicablepre-commithook reportsPassed, includingisort,black,flake8,ruffandcodespell.The shutdown chain the graceful rows depend on was exercised directly, without a GPU, against the real
components/src/dynamo/common/utils/graceful_shutdown.pyand the realBaseWorkerHandler._abort_monitorfromcomponents/src/dynamo/vllm/handlers.py, with only the compileddynamo._coreextension and the engine client stubbed.graceful_shutdown_with_discoveryreachedshutdown_event.set()0.000safter entry withDYN_GRACEFUL_SHUTDOWN_GRACE_PERIOD_SECS=0, and did so before the cleanup callback rather than after it, so engine teardown does not delay the notification. Setting that event drove the real abort monitor to callengine_client.abort("req-1")and raiseEngineShutdown: Engine was shut down during generation.out of the body the context manager wraps.The graceful-shutdown rows themselves were not run. They carry the
fault_toleranceandnightlymarkers and need two live backend workers plus a frontend. On the machine used here the GPU driver reports CUDA 12.8 while the installed PyTorch 2.11.0 and vLLM 0.26.0 are built for CUDA 13.0, sotorch.cuda.init()raisesThe NVIDIA driver on your system is too old (found version 12080)and no vLLM worker starts. A nightly GPU run is what confirms these rows end to end.Related Issues
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