nfd-gc: Remove stale NRT objects

[ozhuraki]

Remove stale NRT objects whose creator pod does not exist anymore.

Closes #1586

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is NOT APPROVED

This pull-request has been approved by: ozhuraki
Once this PR has been reviewed and has the lgtm label, please assign marquiz for approval. For more information see the Kubernetes Code Review Process.

The full list of commands accepted by this bot can be found here.

Needs approval from an approver in each of these files:

• OWNERS

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[k8s-ci-robot]

Hi @ozhuraki. Thanks for your PR.

I'm waiting for a kubernetes-sigs member to verify that this patch is reasonable to test. If it is, they should reply with /ok-to-test on its own line. Until that is done, I will not automatically test new commits in this PR, but the usual testing commands by org members will still work. Regular contributors should join the org to skip this step.

Once the patch is verified, the new status will be reflected by the ok-to-test label.

I understand the commands that are listed here.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[netlify]

✅ Deploy Preview for kubernetes-sigs-nfd ready!

Name	Link
🔨 Latest commit	b5fee22
🔍 Latest deploy log	https://app.netlify.com/sites/kubernetes-sigs-nfd/deploys/670eb02cb2c76d00083c3cb5
😎 Deploy Preview	https://deploy-preview-1700--kubernetes-sigs-nfd.netlify.app
📱 Preview on mobile	Toggle QR Code... Use your smartphone camera to open QR code link.

---

To edit notification comments on pull requests, go to your Netlify site configuration.

[ArangoGutierrez]

/ok-to-test

[ozhuraki]

@PiotrProkop @ArangoGutierrez

Thanks! Updated, please take a look

[ozhuraki]

@PiotrProkop @ArangoGutierrez

Updated unit tests, please take a look

[PiotrProkop]

@ozhuraki @ArangoGutierrez one question, if we upgrade NFD-gc on existing cluster with this feature, it would remove all NRTs in the cluster cause none of them, has the owner-pod labels? Is it acceptable? Even if NRTs would be recreated after some time automatically it can lead to some downtime for components leveraging NRTs like topo-aware-scheduler.
/cc @ffromani

[ozhuraki]

@PiotrProkop
Thanks for the input. Yes, this would happen.

I updated it so that NRT is garbage collected only when it has label, please take a look.

[marquiz]

Thanks @ozhuraki for the PR. A few comments from me below.

@PiotrProkop PTAL

[ozhuraki]

@marquiz
Thanks! Updated, please take a look

[marquiz]

Thanks for the update @ozhuraki. I identified a few possible race issues but those shouldn't be too hard to solve.

[codecov]

Codecov Report

Attention: Patch coverage is 29.41176% with 12 lines in your changes missing coverage. Please review.

Project coverage is 39.52%. Comparing base (b9770b1) to head (665abb9).
Report is 142 commits behind head on master.

Additional details and impacted files

@@            Coverage Diff             @@
##           master    #1700      +/-   ##
==========================================
- Coverage   39.84%   39.52%   -0.33%     
==========================================
  Files          80       80              
  Lines        6841     7170     +329     
==========================================
+ Hits         2726     2834     +108     
- Misses       3861     4075     +214     
- Partials      254      261       +7     

Files	Coverage Δ
pkg/nfd-topology-updater/nfd-topology-updater.go	2.50% <0.00%> (-0.01%)	⬇️
pkg/nfd-gc/nfd-gc.go	32.69% <31.25%> (-0.17%)	⬇️

... and 14 files with indirect coverage changes

[ozhuraki]

@marquiz @PiotrProkop

Thanks for the help here and apologies, missed your comments.

Updated per your suggestion to solve the race and rebased, please take a look

[k8s-ci-robot]

PR needs rebase.

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes-sigs/prow repository.

[ozhuraki]

@marquiz

Thanks for the useful input. Updated, please take a look