Drop support for docker log format

[saschagrunert]

What type of PR is this?

/kind cleanup

What this PR does / why we need it:

Dockershim has been removed from Kubernetes so we only need to support the CRI log format.

Which issue(s) this PR fixes:

None

Special notes for your reviewer:

None

Does this PR introduce a user-facing change?

Removed support for docker log format in tests since dockershim is not available in Kubernetes any more.

[k8s-ci-robot]

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[haircommander]

/lgtm

[SergeyKanzhelev]

Sorry for the late comment. Will this work with CRI-DOCKERD? We are not dropping this from kubelet because of cri-dockerd to protect back compat.

[haircommander]

cri-dockerd should log in cri format IMO

[SergeyKanzhelev]

Do you know any maintainers of cri-dockerd? @nwneisen I see you are making releases. please advice

[nwneisen]

@SergeyKanzhelev I recently took over cri-dockerd. The project uses k8s.io/klog/v2 which looks like the output can be configured. The logs I've seen have been in the logfmt format

[haircommander]

@nwneisen in this case we're talking about container logs--how does cri-dockerd write logs to disk for the kubelet to read them?

[nwneisen]

{"log":"I0719 22:04:51.982483       1 log.go:195] Started HTTP server on port 8080\n","stream":"stderr","time":"2023-07-19T22:04:51.993532538Z"}
{"log":"I0719 22:04:51.982923       1 log.go:195] Started UDP server on port  8081\n","stream":"stderr","time":"2023-07-19T22:04:51.993575341Z"}
{"log":"I0719 22:05:48.595826       1 log.go:195] GET /\n","stream":"stderr","time":"2023-07-19T22:05:48.595996805Z"}
{"log":"I0719 22:05:48.618534       1 log.go:195] GET /\n","stream":"stderr","time":"2023-07-19T22:05:48.618656559Z"}

Container logs are being written to disk in json format. I agree that cri-dockerd should use cri format. I will work on making a change for this.

[saschagrunert]

Thank you @nwneisen! 🙏