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Add backoff mechanism for ProvReq retry #7182

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Add backoff mechanism for ProvReq retry #7182

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yaroslava-serdiuk
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What type of PR is this?

/kind feature

@k8s-ci-robot k8s-ci-robot added kind/feature Categorizes issue or PR as related to a new feature. cncf-cla: yes Indicates the PR's author has signed the CNCF CLA. labels Aug 19, 2024
@k8s-ci-robot k8s-ci-robot added area/cluster-autoscaler size/S Denotes a PR that changes 10-29 lines, ignoring generated files. labels Aug 19, 2024
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/cc @aleksandra-malinowska

@k8s-ci-robot k8s-ci-robot added size/M Denotes a PR that changes 30-99 lines, ignoring generated files. and removed size/S Denotes a PR that changes 10-29 lines, ignoring generated files. labels Aug 19, 2024
aleksandra-malinowska
aleksandra-malinowska reviewed Aug 19, 2024
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cluster-autoscaler/processors/provreq/injector.go Outdated
defaultRetryTime = 10 * time.Minute
defaultRetryTime = 1 * time.Minute
maxBackoffTime = 10 * time.Minute
maxCacheSize = 1000
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I'm not 100% sure if that'll be sufficient long-term. It doesn't sound like it'll scale very well, since it effectively disables any backoff when there are more than 1k failing ProvReqs - i.e., precisely when a backoff would be most useful for preventing starvation of other requests.

Can you add a todo to clean up ProvReqs when they're resolved (succeed, time out, or are deleted)?

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To be clear, I'm OK with merging it as is, but I think we should leave a note that it's a stopgap solution.

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Done, also removed elements that are provisioned or failed

@yaroslava-serdiuk yaroslava-serdiuk force-pushed the provreq-retry branch 2 times, most recently from c7dbebc to 242edc5 Compare August 20, 2024 08:58
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/hold

@k8s-ci-robot k8s-ci-robot added the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Aug 20, 2024
aleksandra-malinowska
aleksandra-malinowska approved these changes Aug 20, 2024
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/lgtm
/approve

Please add a test case for this.

cluster-autoscaler/processors/provreq/injector_test.go Outdated
@@ -117,7 +117,8 @@ func TestProvisioningRequestPodsInjector(t *testing.T) {
}
for _, tc := range testCases {
client := provreqclient.NewFakeProvisioningRequestClient(context.Background(), t, tc.provReqs...)
injector := ProvisioningRequestPodsInjector{client, clock.NewFakePassiveClock(now)}
backoffTime := map[string]time.Duration{key(notProvisionedRecentlyProvReqB): 2 * time.Minute}
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Maybe add a new test case for backed off request scenario?

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I put backed off request scenario in a separate case

@k8s-ci-robot k8s-ci-robot added lgtm "Looks good to me", indicates that a PR is ready to be merged. approved Indicates a PR has been approved by an approver from all required OWNERS files. labels Aug 20, 2024
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/approve cancel

@k8s-ci-robot k8s-ci-robot added needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. and removed approved Indicates a PR has been approved by an approver from all required OWNERS files. labels Aug 20, 2024
mwielgus
mwielgus reviewed Sep 5, 2024
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cluster-autoscaler/processors/provreq/injector.go Outdated
"k8s.io/client-go/rest"
"k8s.io/klog/v2"
"k8s.io/utils/clock"
)

const (
defaultRetryTime = 10 * time.Minute
defaultRetryTime = 1 * time.Minute
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Please make it a flag.

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This is initial retry time. What the reasoning to make it configurable?

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In this case let's make maxBackoffTime a flag too. And possibly maxCacheSize as well, so the cluster admin can override it as a mitigation if they run into issues with overflowing cache.

Not that I like adding lots of flags to an already impressive collection, but Kueue depends on this feature and CA has a much higher fix-to-release latency and cost (or so it seems), so let's not risk getting stuck with hardcoded values.

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There is context there: kubernetes-sigs/kueue#2931
Kueue got some requests for this retry time.

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@aleksandra-malinowska aleksandra-malinowska Sep 5, 2024 •
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@yaroslava-serdiuk I believe it's about kubernetes-sigs/kueue#2931 (reply in thread). But my previous comment stands, let's make it configurable and easy to mitigate. It's not like we have any data supporting this choice of hardcoded values AFAIK.

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The "right" initial value depends on (at least) 2 factors:

  • size of the cluster and, so, the number of incoming provisioning requests.
  • the performance/throughput of provrequ processing.

We have no control over the first item, and the second item is being improved right now. So there is no easy way of knowing what value is good now, and, more importantly what value will be OK in 3 months. Having it hardcoded makes any adjustment/finetuning much harder.

@aleksandra-malinowska aleksandra-malinowska mentioned this pull request Sep 6, 2024
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@k8s-ci-robot k8s-ci-robot removed the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Sep 9, 2024
@k8s-ci-robot k8s-ci-robot removed the needs-rebase Indicates a PR cannot be merged because it has merge conflicts with HEAD. label Sep 9, 2024
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/label tide/merge-method-squash

@k8s-ci-robot k8s-ci-robot added the tide/merge-method-squash Denotes a PR that should be squashed by tide when it merges. label Sep 10, 2024
aleksandra-malinowska
aleksandra-malinowska reviewed Sep 11, 2024
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cluster-autoscaler/processors/provreq/injector.go Outdated
for _, pr := range provReqs {
if !isSupportedClass(pr) {
klog.Warningf("Provisioning Class %s is not supported for ProvReq %s/%s", pr.Spec.ProvisioningClassName, pr.Namespace, pr.Name)
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I don't think we want to log the warning here. This method will be used in batch processing of check-capacity requests with a custom isSupportedClass function, and we'd end up logging it for best-effort-atomic-scale-up requests.

Can we move logging this to the isSupportedClass function defined in Process() instead?

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I can't anchor comment there but what I mean is:

		func(pr *provreqwrapper.ProvisioningRequest) bool {
			_, found := provisioningrequest.SupportedProvisioningClasses[pr.Spec.ProvisioningClassName]
			if !found {
				klog.Warningf("Provisioning Class %s is not supported for ProvReq %s/%s", pr.Spec.ProvisioningClassName, pr.Namespace, pr.Name)
			}
			return found
		})

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Done

@aleksandra-malinowska
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Thanks for moving this to use LRU cache, looks much better! One small comment, otherwise it's good to go. Feel free to unhold when you're ready to merge this.

/lgtm
/approve

/hold

@k8s-ci-robot k8s-ci-robot added the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Sep 11, 2024
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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: aleksandra-malinowska, yaroslava-serdiuk

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@k8s-ci-robot k8s-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Sep 11, 2024
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New changes are detected. LGTM label has been removed.

@k8s-ci-robot k8s-ci-robot removed the lgtm "Looks good to me", indicates that a PR is ready to be merged. label Sep 11, 2024
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/unhold

@k8s-ci-robot k8s-ci-robot removed the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Sep 19, 2024
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/hold

@k8s-ci-robot k8s-ci-robot added the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Sep 19, 2024
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/unhold

@k8s-ci-robot k8s-ci-robot removed the do-not-merge/hold Indicates that a PR should not merge because someone has issued a /hold command. label Sep 19, 2024
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@aleksandra-malinowska aleksandra-malinowska aleksandra-malinowska approved these changes

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