✨ refuse a restore onto a different MIG partitioning or shape - #318
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nvidia-smi reports a MIG slice under its parent card's product name, so a whole H100 and a 1g.10gb slice of one are the same model and the same count. gpu-model and gpu-count both pass, and the restore fails later inside CRIU or the CUDA runtime on memory or SM capacity instead. Two rules rather than one, because they rest on different recorded data. mig-partitioning reads the GPU UUIDs, which have been recorded since the first release and carry a MIG- prefix only for a slice, so it refuses a whole GPU against a slice on artifacts captured by any version. mig-profile compares the slice shape, which needs a value nothing records yet; until one is recorded the shape stays unknown, and an unknown value admits, as mustMatch already documents. Both summarise which values are present and not how many devices share each, so losing a GPU is reported once by gpu-count rather than twice. Signed-off-by: liran elisha <lirane@nvidia.com>
--query-gpu exposes no MIG field at all, so the slice shape has to come from nvidia-smi -L, which lists it beside each slice's own UUID. Discovery makes that second call and joins the profiles onto the devices it already found, keyed on UUID rather than on position. A device no profile was listed for keeps none, which leaves the shape unknown instead of guessing at it. For the same reason a failed listing returns the GPUs it did read: the profile is a description, so losing it costs the shape comparison rather than the checkpoint. Signed-off-by: liran elisha <lirane@nvidia.com>
status.source publishes what a checkpoint was captured on, and the model name alone cannot say whether that was a whole card or a slice of one. The profile is the only published value that distinguishes them, so it belongs next to the model rather than being left to inference. CRD change. Absent when the capture had a whole GPU, and absent for a slice captured before the profile was recorded. Signed-off-by: liran elisha <lirane@nvidia.com>
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Included review availability: Your plan provides up to 12 included reviews per hour; 9 remain after this review. WalkthroughThe change discovers MIG profiles, persists them in manifests, publishes them in checkpoint source status, and validates MIG partitioning and profile compatibility during restore checks. ChangesMIG compatibility
Priority: ➖ Normal Estimated code review effort: 3 (Moderate) | ~25 minutes Severity of issue fixed: Medium Sequence Diagram(s)sequenceDiagram
participant NvidiaSMI
participant DiscoverVisibleGPUs
participant GPUManifest
participant CompatibilityChecks
NvidiaSMI->>DiscoverVisibleGPUs: Return GPU query and MIG listing
DiscoverVisibleGPUs->>GPUManifest: Store UUID and MIGProfile
GPUManifest->>CompatibilityChecks: Provide recorded GPU devices
CompatibilityChecks->>CompatibilityChecks: Compare partitioning and profiles
Merge Risk: ⚪ Minimal · up to The MIG compatibility changes have no verified current-head issue requiring a merge block. 🚥 Pre-merge checks | ✅ 5 | ❌ 2❌ Failed checks (2 warnings)
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In `@api/compat/checks.go`:
- Around line 419-423: Update distinctSorted and the MIG compatibility checks to
preserve multiplicity by producing a sorted summary with each value’s occurrence
count instead of deduplicating values. Keep existing formatting for single
occurrences and append xN for repeated values, including mixed whole-GPU and
MIG-slice profiles; add regression cases covering equal device totals with
different profile multiplicities.
In `@api/compat/compat.go`:
- Around line 73-75: Add the `// +optional` marker immediately before the
exported `MIGProfile` field declaration in the relevant compatibility type,
leaving its existing comment and behavior unchanged.
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CHANGELOG.mdagent/internal/controller/checkpointsource.goagent/internal/controller/checkpointsource_test.goagent/internal/cuda/cuda.goagent/internal/cuda/cuda_test.goagent/internal/types/manifest.goapi/compat/checks.goapi/compat/checks_test.goapi/compat/compat.goapi/v1alpha1/checkpoint_source_types.goapi/v1alpha1/crds/nvidia.com_podsnapshotcontents.yamldocs/reference/api.md
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gpu-count compares only the total, so dropping the counts from the shape summary left two slices of one shape and one of another indistinguishable from the reverse: three devices either way, one parent model either way, and the same set of shapes either way. mig-profile admitted it. The shapes are counted again. The partitioning summary stays categorical, because which kinds are present is a yes-or-no question and counting it there would refuse every plain change in GPU count on a cluster with no MIG at all, restating gpu-count under a name mentioning MIG. Signed-off-by: liran elisha <lirane@nvidia.com>
Which kinds of device a set of GPUs holds is two independent booleans, not a list: each device is either a whole card or a slice, and a set can hold both. The slice the summary was built from carried order and multiplicity that the renderer immediately discarded, and its distinctSorted helper had no other caller. The rendered value is unchanged, so refusal messages and conditions read exactly as before and the existing tests pass untouched. Signed-off-by: liran elisha <lirane@nvidia.com>
nvidia-smi -L writes each MIG device as a fixed run of whitespace-padded columns, and strings.Fields collapses that padding on its own, so the pattern's repeated whitespace groups were doing work the standard library already does. Naming each column says what the line is made of in a way the pattern could only imply, and the device ordinal is still checked to be a number rather than merely present. Both forms were run over the existing inputs, the listing from the T4 this was validated on, the older MIG-GPU-<parent>/<gi>/<ci> UUID spelling, a media-extension profile, tab and single-space padding, and trailing text, and they agree throughout. Those inputs are now test cases. Signed-off-by: liran elisha <lirane@nvidia.com>
An absent profile has two causes, and only one of them is a fact about the GPU: a whole-GPU capture never had a shape to record, while an agent released before this field captured slices without recording theirs. The wording led with the first and buried the second, and the API reference gave only the first, so it implied exactly the inference the gates are built to avoid. Whole against slice is decided from the UUID for this reason, and an absent shape admits a restore rather than refusing one. Regenerated both CRD copies, since the field description ships in them. Signed-off-by: liran elisha <lirane@nvidia.com>
It explained why the model name cannot stand in for the profile, which is motivation for the field rather than a description of it, and reading it on the field itself invited the question of what ProductName had to do with the value at hand. Signed-off-by: liran elisha <lirane@nvidia.com>
gpu-model and mig-profile compared the string summariseByCount returned, which made its sort load-bearing for correctness rather than cosmetic: it iterates a map, so without the sort two identical sets could render in different orders and compare unequal. Nothing at the call site said so. The comparison is now its own function that says what it ignores, and summariseByCount drops to rendering the refusal message, where the count still matters because a node holding eight of one GPU should not print eight entries. Every existing assertion passes untouched, including the two that pin order independence. Signed-off-by: liran elisha <lirane@nvidia.com>
testify's ElementsMatch answers the same question and is already what this repository's tests call it, and the name sits beside mustMatch in this file as its multi-value counterpart. Signed-off-by: liran elisha <lirane@nvidia.com>
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Closes #317, the first check carved out of the rule-set in #232.
What was wrong
nvidia-smireports a MIG slice under its parent card's product name, and--query-gpuexposes no MIG field at all. So a checkpoint taken on a whole H100and restored onto a
1g.10gbslice of an H100 saw the same model on both sidesand one device on both sides:
gpu-modelpassed,gpu-countpassed, and therestore failed later inside CRIU or the CUDA runtime on memory or SM capacity.
The same held across differently shaped slices,
3g.40gbonto1g.10gb.That is the failure mode the gates added in #140 exist to prevent — an error
describing a symptom rather than the cause.
What this does
Two named checks rather than one, because they rest on different recorded data.
mig-partitioningmig-profilemig-partitioningreads the GPU UUIDs, which have been recorded since the firstrelease and carry a
MIG-prefix only for a slice — in both the currentMIG-<uuid>form and the olderMIG-GPU-<parent>/<gi>/<ci>one. So it needs nonew capture field and reaches artifacts captured before this change.
mig-profileneeds the shape, which onlynvidia-smi -Lpublishes, so capturemakes a second call and joins the profiles onto the devices discovery already
found, keyed on UUID rather than position. An artifact carrying no profile
leaves the shape unknown, and an unknown value admits — the policy
mustMatchalready documents, so a checkpoint captured before a value was recorded stays
restorable.
Both checks compare which values are present rather than how many devices
share each, so losing a GPU is reported once by
gpu-countinstead of twiceunder two names.
The profile is also published on
status.source.devices.nvidia.instances[].migProfile, so what a user reads isthe value the gate compares. CRD change, and the field is absent both for a
whole-GPU capture and for a slice captured before it existed.
Reading order
Three commits, each building and passing its own tests standalone:
feat(compat)— the two rules and their tests, against synthetic datafeat(cuda)— reading the profile at capture and recording itfeat(api)— publishing it, plus the CRD, API reference and changelogTest plan
apiandoperator: lint clean, tests passagent: full suite and lint clean inside thegolang:1.27.1container(
internal/runtimeis Linux-only, so neither runs natively on macOS)make generatereproduces the CRDs with the chart copy in sync;verify-crds,helm-lint, license headers,fmtandtidyall cleanin both directions and the legacy-artifact paths; the
nvidia-smi -Lparseragainst real multi-slice output, a MIG-disabled node and an empty listing;
discovery surviving a failed listing; and the status projection
No unit test needs GPU or MIG hardware, per the acceptance criteria.
Validated on a real GPU cluster
Validated at
35a3f3e, published asv0.0.0-lirane-mig-profile-restore-gat-g35a3f3edand installed as the runningagent, operator and CRDs on a single-GPU cluster: Tesla T4, driver
595.71.05, kernel7.0.0-1012-aws, GPU Operatorv26.3.3.8624180landed after that run, and changes only how the partitioning value isheld in memory — the rendered strings the gate compares and reports are
unchanged, byte for byte, which the unmodified tests and a replay of the
comparison against these same T4 values both confirm.
The new
nvidia-smi -Lcall reaches the GPU. Run throughnsenterinto alive container's mount and PID namespaces, exactly as capture does:
Both calls report the same UUID, which is the key the profiles are joined
on.
A whole-GPU capture records and publishes no profile. The manifest on the
volume, and the status the operator published from it:
migProfileis absent on both sides, which is what a whole GPU should record.Restoring that artifact unmodified gives
Restored=True/RestoreSucceeded, soneither new check refuses a restore it should admit.
mig-partitioningrefuses a slice against a whole GPU. Flipping only theprefix of the recorded UUID, leaving
productNameand thesourceGpuUuidslist that the device map is built from untouched, so the restore would have
succeeded had the check not read it:
with a matching
RestoreIncompatibleevent on the pod. That is theretroactive path: an artifact carrying a recorded UUID and no profile field at
all is still refused across the whole-versus-slice boundary, and
mig-profilestays quiet because the target offers no slice to compare a shape against.
The e2e suite is 23 of 24.
test_orphan_scanner_reclaims_uid_rootplants anorphan artifact root and asserts it exists before the operator's cleanup scan
removes it, which races the 5-second scan interval the e2e setup configures; it
passed 3 of 4 reruns. It is a CPU-only test, and nothing in this change touches
the operator or the cleanup path.
Not yet confirmed on hardware
No MIG-capable GPU was reachable — the only GPU node is a T4, which the GPU
Operator labels
nvidia.com/mig.capable=false, and the real-GPU pools offer T4or A10G, neither of which partitions. So
mig-profile's shape against shaperefusal is covered by unit tests alone;
mig-partitioningis confirmed above inboth the admit and the refuse direction.
The open question narrows rather than closes. On a whole GPU the two
nvidia-smicalls agree on the UUID, as shown above, so the join works. Whatremains unknown is whether
--query-gpu=gpu_uuidreports the slice UUID or theparent card's inside a container holding only a MIG device. If the two disagree
there, the profile stays unknown and
mig-profileadmits rather than wronglyrefusing — safe in the conservative direction, but it means the shape half wants
confirming on a real MIG node before it is called enforced.
mig-partitioningdoes not depend on this, since it reads UUIDs that are already recorded and
already correct.
Review ownership
Touches
api/compat(the rules),agent/internal/cuda(capture), and thePodSnapshotContentstatus contract. The compat and CRD changes are the onesworth the most attention.
Summary by CodeRabbit
New Features
Bug Fixes
Documentation
migProfilecheckpoint metadata and availability rules.