feat(metrics): consecutiveSoftErrors

[AndrewCharlesHay]

What does it do ?

• New Metric Added

  • Added a Prometheus gauge metric: external_dns_controller_consecutive_soft_errors
  • This metric tracks the number of consecutive soft errors (non-fatal, retryable errors) encountered during the controller’s reconciliation loop.

• Metric Registration

  • Registered the new consecutiveSoftErrors metric with the existing set of metrics.

• Enhanced Error Handling in Controller Loop

  • Introduced a softErrorCount counter to track consecutive soft errors.
  • On each soft error:
    • Increment the counter.
    • Update the Prometheus metric.
    • Log the error including the current consecutive count.
  • On successful reconciliation after soft errors:
    • Log the recovery and count of previous consecutive soft errors.
    • Reset the counter and metric to zero.

Benefit:
These changes provide improved observability for persistent, non-fatal issues in the controller’s reconciliation loop, making it easier to detect and troubleshoot recurring problems.

Motivation

#5499

More

• Yes, this PR title follows Conventional Commits
• Yes, I added unit tests
• Yes, I updated end user documentation accordingly

[k8s-ci-robot]

Hi @AndrewCharlesHay. 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.

[mloiseleur]

Very interesting, thanks @AndrewCharlesHay 👍
/ok-to-test
cc @szuecs

[ivankatliarchuk]

linter is fixed, worth to rebase

[szuecs]

/lgtm

[mloiseleur]

@AndrewCharlesHay It LGTM. Can you fix the linter ? After, we should be good to go.

[AndrewCharlesHay]

Will do

[ivankatliarchuk]

/lgtm
/approve

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: ivankatliarchuk

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

The pull request process is described here

Needs approval from an approver in each of these files:

• OWNERS [ivankatliarchuk]

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

[ivankatliarchuk]

Not sure how easy to reproduce, seems like we have a flaky test https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/kubernetes-sigs_external-dns/5498/pull-external-dns-unit-test/1931045324659363840

[ivankatliarchuk]

Hi @AndrewCharlesHay
We keep getting test failures for our end-2-end
example PR #5509
and failed test https://prow.k8s.io/view/gs/kubernetes-ci-logs/pr-logs/pull/kubernetes-sigs_external-dns/5509/pull-external-dns-unit-test/1932014905611784192

What the difference is, I'm not sure. It works on github actions and failes in PROW

not 100% related kubernetes-sigs/prow#450

[ivankatliarchuk]

#5509 (comment)