Is there a way nerdctl logs to show logs from containers started by kubelet.

[jeffgtxjava]

Based on the FAQ's here I assumed nerdctl would be able to fetch the logs from the containers started by kubelet.

Any specific reason why it wont show logs while it can ps, inspect and even exec

Logs

-sh-4.2# nerdctl logs 92b39c8386ef 
WARN[0000] Currently, `nerdctl logs` only supports containers created with `nerdctl run -d` 
FATA[0000] open /cowdata/nerd-bootstrap/29c6aec2/containers/92b39c8386ef758e2327a26c1070771c6d91f9365f74a4241f691f1327267c0c/log-config.json: no such file or directory 
-sh-4.2# nerdctl inspect 92b39c8386ef | wc -l
89

Inspect

-sh-4.2# nerdctl inspect 92b39c8386ef | wc -l
89

Exec

-sh-4.2# nerdctl exec -it 92b39c8386ef date
Wed Jul  6 12:25:42 GMT 2022

NOTE: crictl is able to do the same.

-sh-4.2# crictl logs 92b39c8386ef &> /tmp/testlogs

-sh-4.2# wc -l /tmp/testlogs 
24 /tmp/testlogs
-sh-4.2# 

[AkihiroSuda]

Any specific reason why it wont show logs while it can ps, inspect and even exec

Because containerd still lacks high-level logging infrastructure.
nerdctl implements its own logging drivers (json-file, journald, fluentd) to emulate the UX of Docker, while the CRI implements its own logging driver.

[jeffgtxjava]

@AkihiroSuda Just trying to understand more. Apologies for my tech ignorance. Isn't crictl logs also operating on top of same containerd. I was under assumption we can create a task on containerd to get the logs.

[AkihiroSuda]

Same daemon, but different logging infra.

If we want to let nerdctl read CRI logs we will have to duplicate the logic from https://github.com/kubernetes/kubernetes/blob/v1.24.2/pkg/kubelet/kuberuntime/logs/logs.go

[jeffgtxjava]

@AkihiroSuda Should we create a issue so it would eventually get picked up as a feature request?

I feel this would be a great addition as we are able to perform inspect, exec and multiple other operations on the containers started by kubelet and would help ppl migrate from docker post docker-shim deprecation.

[AkihiroSuda]

Yes, please

[fahedouch]

@jeffgtxjava we have a ticket that raise logging driver implen we can ask for implementation here #1039