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Percona Documentation

Check the Logs

Logs provide valuable information. It makes sense to check the logs of the database Pods and the Operator Pod. Following flags are helpful for checking the logs with the kubectl logs command:

Flag Description
--container=<container-name> Print log of a specific container in case of multiple containers in a Pod
--follow Follows the logs for a live output
--since=<time> Print logs newer than the specified time, for example: --since="10s"
--timestamps Print timestamp in the logs (timezone is taken from the container)
--previous Print previous instantiation of a container. This is extremely useful in case of container restart, where there is a need to check the logs on why the container restarted. Logs of previous instantiation might not be available in all the cases.

In the following examples we will access containers of the cluster1-pxc-0 Pod.

  • Check logs of the pxc container:

    $ kubectl logs cluster1-pxc-0 -c pxc

  • Check logs of the pmm-client container:

    $ kubectl logs cluster1-pxc-0 -c pmm-client

  • Filter logs of the pxc container which are not older than 600 seconds:

    $ kubectl logs cluster1-pxc-0 -c pxc --since=600s

  • Check logs of a previous instantiation of the pxc container, if any:

    $ kubectl logs cluster1-pxc-0 -c pxc --previous

  • Check logs of the pxc container, parsing the output with jq JSON processor :

    $ kubectl logs cluster1-pxc-0 -c pxc -f | jq -R 'fromjson?'

Cluster-level logging

Cluster-level logging involves collecting logs from all Percona XtraDB Cluster Pods in the cluster to some persistent storage. This feature gives the logs a lifecycle independent of nodes, Pods and containers in which they were collected. Particularly, it ensures that Pod logs from previous failures are available for later review.

Log collector is turned on by the logcollector.enabled key in the deploy/cr.yaml configuration file (true by default).

The Operator collects logs using Fluent Bit Log Processor , which supports many output plugins and has broad forwarding capabilities. If necessary, Fluent Bit filtering and advanced features can be configured via the logcollector.configuration key in the deploy/cr.yaml configuration file.

Logs are stored for 7 days and then rotated.

Collected logs can be examined using the following command:

$ kubectl logs cluster1-pxc-0 -c logs

Note

Technically, logs are stored on the same Persistent Volume, which is used with the corresponding Percona XtraDB Cluster Pod. Therefore collected logs can be found in DATADIR (var/lib/mysql/). Also, there is an additional Secrets object for Fluent Bit passwords and other similar data, e.g. for output plugins. The name of this Secrets object can be found in the logCollectorSecretName option of the Custom Resource (it is set to my-log-collector-secrets in the deploy/cr.yaml configuration file by default).

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Last update: 2024-10-16