- I am pretty sure it writes it on disk somewhere. Otherwise if the container runs for several hours and logs a lot, then it would exceed what the stderr can hold I think. No?
- Is it possible to compress and download the logs of kubectl logs?i.e. comparess on the container without downloading them?
Where does K8s store the logs that it prints when running kubectl logs -f
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1 Answers
Firstly take a look on logging-kubernetes official documentation.
In most cases, Docker container logs are put in the /var/log/containers directory on your host (host they are deployed on). Docker supports multiple logging drivers but Kubernetes API does not support driver configuration.
Once a container terminates or restarts, kubelet keeps its logs on the node. To prevent these files from consuming all of the host’s storage, a log rotation mechanism should be set on the node.
You can use kubectl logs to retrieve logs from a previous instantiation of a container with --previous flag, in case the container has crashed.
If you want to take a look at additional logs. For example, in Linux journald logs can be retrieved using the journalctl command:
$ journalctl -u docker
You can implement cluster-level logging and expose or push logs directly from every application but the implementation for such a logging mechanism is not in the scope of Kubernetes.
Also there are many tools offered for Kubernetes for logging management and aggregation - see: logs-tools.
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