Dynamic resource allocation is similar to storage in the sense that users
create ResourceClaim objects to request resources, same as with persistent
volume claims. The actual resource usage is only known when allocating claims,
but some limits can already be enforced at admission time:
- "count/resourceclaims.resource.k8s.io" limits the number of ResourceClaim objects in
a namespace; this is a generic feature that is already supported also without
this commit.
- "resourceclaims" is *not* an alias - use "count/resourceclaims.resource.k8s.io"
instead.
- <device-class-name>.deviceclass.resource.k8s.io/devices limits the number of
ResourceClaim objects in a namespace such that the number of devices
requested through those objects with that class does not exceed the limit.
A single request may cause the allocation of multiple devices. For exact
counts, the quota limit is based on the sum of those exact counts. For requests
asking for "all" matching devices, the maximum number of allocated devices per
claim is used as a worst-case upper bound.
Requests asking for "admin access" contribute to the quota.
DRA quota: remove admin mode exception
The names aren't actually special for validation. They are
acceptable with and without the feature gate, the only difference
is that they don't do anything when the feature is enabled.
Some of the E2E node tests were flaky. Their timeout apparently was chosen
under the assumption that kubelet would retry immediately after a failed gRPC
call, with a factor of 2 as safety margin. But according to
0449cef8fd,
kubelet has a different, higher retry period of 90 seconds, which was exactly
the test timeout. The test timeout has to be higher than that.
As the tests don't use the gRPC call timeout anymore, it can be made
private. While at it, the name and documentation gets updated.
In the API, the effect of the feature gate is that alpha fields get dropped on
create. They get preserved during updates if already set. The
PodSchedulingContext registration is *not* restricted by the feature gate.
This enables deleting stale PodSchedulingContext objects after disabling
the feature gate.
The scheduler checks the new feature gate before setting up an informer for
PodSchedulingContext objects and when deciding whether it can schedule a
pod. If any claim depends on a control plane controller, the scheduler bails
out, leading to:
Status: Pending
...
Warning FailedScheduling 73s default-scheduler 0/1 nodes are available: resourceclaim depends on disabled DRAControlPlaneController feature. no new claims to deallocate, preemption: 0/1 nodes are available: 1 Preemption is not helpful for scheduling.
The rest of the changes prepare for testing the new feature separately from
"structured parameters". The goal is to have base "dra" jobs which just enable
and test those, then "classic-dra" jobs which add DRAControlPlaneController.
The structured parameter allocation logic was written from scratch in
staging/src/k8s.io/dynamic-resource-allocation/structured where it might be
useful for out-of-tree components.
Besides the new features (amount, admin access) and API it now supports
backtracking when the initial device selection doesn't lead to a complete
allocation of all claims.
Co-authored-by: Ed Bartosh <eduard.bartosh@intel.com>
Co-authored-by: John Belamaric <jbelamaric@google.com>
The resource claim controller is completely agnostic to the claim spec. It
doesn't care about classes or devices, therefore it needs no changes in 1.31
besides the v1alpha2 -> v1alpha3 renaming from a previous commit.
This adds the ability to select specific requests inside a claim for a
container.
NodePrepareResources is always called, even if the claim is not used by any
container. This could be useful for drivers where that call has some effect
other than injecting CDI device IDs into containers. It also ensures that
drivers can validate configs.
The pod resource API can no longer report a class for each claim because there
is no such 1:1 relationship anymore. Instead, that API reports claim,
API devices (with driver/pool/device as ID) and CDI device IDs. The kubelet
itself doesn't extract that information from the claim. Instead, it relies on
drivers to report this information when the claim gets prepared. This isolates
the kubelet from API changes.
Because of a faulty E2E test, kubelet was told to contact the wrong driver for
a claim. This was not visible in the kubelet log output. Now changes to the
claim info cache are getting logged. While at it, naming of variables and some
existing log output gets harmonized.
Co-authored-by: Oksana Baranova <oksana.baranova@intel.com>
Co-authored-by: Ed Bartosh <eduard.bartosh@intel.com>
This is a complete revamp of the original API. Some of the key
differences:
- refocused on structured parameters and allocating devices
- support for constraints across devices
- support for allocating "all" or a fixed amount
of similar devices in a single request
- no class for ResourceClaims, instead individual
device requests are associated with a mandatory
DeviceClass
For the sake of simplicity, optional basic types (ints, strings) where the null
value is the default are represented as values in the API types. This makes Go
code simpler because it doesn't have to check for nil (consumers) and values
can be set directly (producers). The effect is that in protobuf, these fields
always get encoded because `opt` only has an effect for pointers.
The roundtrip test data for v1.29.0 and v1.30.0 changes because of the new
"request" field. This is considered acceptable because the entire `claims`
field in the pod spec is still alpha.
The implementation is complete enough to bring up the apiserver.
Adapting other components follows.
Logging and sub-tests were added to help debug this problem:
the test passes for ResourceClaim (same defaulting!) and fails
for the list, but only if run together with the other test cases?!
$ go test ./pkg/api/testing
--- FAIL: TestDefaulting (1.76s)
--- FAIL: TestDefaulting/resource.k8s.io/v1alpha3,_Kind=ResourceClaimList (0.01s)
defaulting_test.go:238: expected resource.k8s.io/v1alpha3, Kind=ResourceClaimList to trigger defaulting due to fuzzing
FAIL
FAIL k8s.io/kubernetes/pkg/api/testing 17.294s
FAIL
$ go test -run=TestDefaulting/resource.k8s.io/v1alpha3,_Kind=ResourceClaimList ./pkg/api/testing
ok k8s.io/kubernetes/pkg/api/testing 0.062s
What fixed that problem was increasing the likelihood of generating the right
test object by iterating more often before giving up.
As agreed in https://github.com/kubernetes/enhancements/pull/4709, immediate
allocation is one of those features which can be removed because it makes no
sense for structured parameters and the justification for classic DRA is weak.
This is in preparation for revamping the resource.k8s.io completely. Because
there will be no support for transitioning from v1alpha2 to v1alpha3, the
roundtrip test data for that API in 1.29 and 1.30 gets removed.
Repeating the version in the import name of the API packages is not really
required. It was done for a while to support simpler grepping for usage of
alpha APIs, but there are better ways for that now. So during this transition,
"resourceapi" gets used instead of "resourcev1alpha3" and the version gets
dropped from informer and lister imports. The advantage is that the next bump
to v1beta1 will affect fewer source code lines.
Only source code where the version really matters (like API registration)
retains the versioned import.
