Version: Release 24.3

Enable File Logging

This topic explains how to enable file logging in the Kubernetes cluster for Release application.

By default, containers don't have file logging enabled to store the logs created by the container applications. In Release, logback.xml file is used for logging. Enabling file logging typically refers to configuring a Release application running within a Kubernetes cluster to generate log files, and possibly directing those logs to a specific location or storage system. Often, we want to save the log files in a persistent storage space so that even if the container restarts, we can retrieve those logs. In such cases, it's a good idea to name the log file using the same name as the pod that creates the logs.

How to Enable File Logging

Get the logback.xml configuration from the container.

kubectl cp digitalai/dai-xlr-digitalai-release-0:conf/logback.xml logback.xml

Edit the logback.xml by adding a file appender (appender-ref) in the desired loggers.

Note

Back up your old configuration by running this command: cp logback.xml logback.xml_backup

POD_NAME is a system variable that the pods have configured.

<configuration>
    ...
    <!-- file log -->
    <appender name="FILE" class="ch.qos.logback.core.FileAppender">
        <file>log/xl-release-${POD_NAME}.log</file>
        <append>true</append>
        <encoder>
            <pattern>%d{yyyy-MM-dd HH:mm:ss.SSS} [%thread] {%mdc} %-5level %logger{36} - %msg%n</pattern>
        </encoder>
    </appender>

    <root level="${LOGBACK_GLOBAL_LOGGING_LEVEL}">
        <appender-ref ref="STDOUT" />
        <appender-ref ref="FILE" />
    </root>
    ...
</configuration>

Create a patch file to update the logback configuration.

c=$(cat logback.xml) \
  yq -n '.spec.extraConfiguration.conf_logback.content = strenv(c)' \
  > xl-release-conf-patch.yaml

Update the configuration patch file by running the following command:

vi xl-release-conf-patch.yaml

Specify the location where logback.xml should be mounted.

spec:
extraConfiguration:
      conf_logback:
          path: "conf/logback.xml"
          content: |
            ...

Additionally, the log directory can be mounted to a persistent volume which can already exist in the cluster. For example, create an emptyDir volume.

spec:
...
extraVolumes:
  - name: log
    emptyDir: {}
extraVolumeMounts:
  - name: log
    mountPath: /opt/xebialabs/xl-release-server/log
    subPath: log

To apply the file to update the configuration, run the following command:

kubectl patch -n digitalai digitalaireleases.xlr.digital.ai dai-xlr \
  --type=merge --patch-file xl-release-conf-patch.yaml

Once the pods are restarted, you will see the following changes:

CR will contain changes that were made.

kubectl get Digitalaireleases dai-xlr -o yaml -n digitalai

Pods will have the additional fields (environment variables, volume mount, and so on).

kubectl get pod dai-xlr-digitalai-release-0 -o yaml -n digitalai

Pods will now be using the new configuration.

kubectl exec -it sts/dai-xlr-digitalai-release -n digitalai \
-- cat /opt/xebialabs/xl-release-server/conf/logback.xml

How to Enable File Logging​

How to Enable File Logging