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What type of PR is this?

/kind bug

/kind ci
/kind cleanup
/kind dependency-change
/kind deprecation
/kind design
/kind documentation
/kind failing-test
/kind feature
/kind flake
/kind other

What this PR does / why we need it:

carries #4394 and #4422
replaces #4421

Which issue(s) this PR fixes:

Special notes for your reviewer:

Does this PR introduce a user-facing change?

Fix a bug where a timeout in RunPodSandbox or CreateContainer requests caused CRI-O to delete the newly created resource. Now, it saves that resource, until the kubelet re-requests it, thus allowing kubelet and CRI-O to reconcile quicker when nodes are under load.

@openshift-ci-robot openshift-ci-robot added release-note Denotes a PR that will be considered when it comes time to generate release notes. kind/bug Categorizes issue or PR as related to a bug. dco-signoff: yes Indicates the PR's author has DCO signed all their commits. labels Dec 10, 2020
@openshift-ci-robot openshift-ci-robot added the approved Indicates a PR has been approved by an approver from all required OWNERS files. label Dec 10, 2020
const sleepTimeBeforeCleanup = 1 * time.Minute

// ResourceStore is a structure that saves information about a recently created resource.
// Resources can be added and retrieved from the store. A retrieval (Get) also removes the Resource from the store.
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a retrieval also removes? That's unusual no?

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I suppose, though here we need to keep a single copy of the resource, so we're basically using move semantics. do you have a suggestion for a better method name?

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/retest

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codecov bot commented Dec 10, 2020

Codecov Report

Merging #4430 (e3dc7e7) into release-1.20 (209938c) will increase coverage by 0.07%.
The diff coverage is 44.18%.

@@               Coverage Diff                @@
##           release-1.20    #4430      +/-   ##
================================================
+ Coverage         40.52%   40.59%   +0.07%     
================================================
  Files               116      117       +1     
  Lines              9327     9404      +77     
================================================
+ Hits               3780     3818      +38     
- Misses             5120     5159      +39     
  Partials            427      427              

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/retest

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/retest

haircommander and others added 10 commits December 10, 2020 13:54
ResourceCache is a structure that keeps track of partially created Pods and Containers.
Its features include:
- tracking pods and containers after their initial creation times out
- automatic garbage collection (after a timer)

Signed-off-by: Peter Hunt <[email protected]>
Before when a client's request for a RunPodSandbox or ContainerCreate timed out, CRI-O would clean up the resource.

However, these requests usually fail when the node is under load. In these cases, it would be better to hold onto the progress,
not get rid of it.

This commit uses the previously created ResourceCache to cache the progress of a container creation and sandbox run.
When a duplicate name is detected, before erroring, the server checks in the ResourceCache to see if we've already
successfully created that resource. If so, we return it as if we'd just created it.

It also moves the SetCreated call to after the resource is deemed as not having timed out.

Hopefully, this reduces the load on already overloaded nodes.

Signed-off-by: Peter Hunt <[email protected]>
Even if we use the resource cache as is, the user is still bombarded with messages saying the name is reserved.

This is bad UX, and we're capable of improving it.

Add watcher idiom to resource cache, allowing a handler routine of RunPodSandbox or CreateContainer to
wait for a resource to be available.

Something that is key here is if the resource becomes available while we're watching for it,
*we still need to error on this request*
This is because we could get the resource from the cache, remove it (thus meaning it won't be cleaned up),
and the kubelet's request could time out, and it could try again. This would cause us to leak a resource.

This way, if we get into this situation, there needs to be three requests:
first that times out
second that discovers the resource is ready, but still errors
third that actually retrives that resource and returns it.

This will result in many fewer "name is reserved" errors (one every 2 seconds to one every 4 minutes)

Signed-off-by: Peter Hunt <[email protected]>
Now that we plan on caching the results of a pod sandbox creation, we shouldn't short circut the
network creation. In a perfect world, we'd give the CNI plugin unbounded time, which would allow
us to reuse even the longest of CNI creation time. However, this leads to the chance that the
CNI plugin runs forever, which is not ideal.

Instead, give the sandbox network creation 5 minutes (a minute more than the full request),
to improve the odds we have a completed sandbox that can be reused, rather than thrown away.

Signed-off-by: Peter Hunt <[email protected]>
timeout.bats is a test suite that tests different scenerios regarding to timeouts in
sandbox running and container creation.

It requires a crictl that knows about the -T option

Signed-off-by: Peter Hunt <[email protected]>
Older version of this code used to have a goroutine for each resource,
which is no longer the case, so remove the obsoleted part of the doc.

It is already described elsewhere how the resource is becoming stale
and removed.

Signed-off-by: Kir Kolyshkin <[email protected]>
The 10s timeout is not enough sometimes to finish container or pod
creation. Increase to 30s to fix occasional flakes, and move to a
separate function wait_crio.

While at it,
 - increate conmon sleep and crictl create/runp cancel timeout to 3s;
 - move create_conmon to setup;
 - fix ID checks (we're looking for string, not substring);
 - change a 3m timeout to 150s. Not critical, just nits.

Signed-off-by: Kir Kolyshkin <[email protected]>
Signed-off-by: Peter Hunt <[email protected]>
@haircommander haircommander added this to the 1.20 milestone Dec 10, 2020
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[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: haircommander, mrunalp

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mrunalp commented Dec 10, 2020

/lgtm

@openshift-ci-robot openshift-ci-robot added the lgtm Indicates that a PR is ready to be merged. label Dec 10, 2020
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/retest

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6 participants