Log Rotate

Log Rotation Configuration

Kylin's log rotation is configured to manage the three log files: shell.stderr, shell.stdout, and kylin.out located in the $KYLIN_HOME/logs/ directory. Any changes to the configurations below require a restart to take effect.

Property	Description	Default Value	Options
kylin.env.max-keep-log-file-number	Maximum number of log files to keep	10
kylin.env.max-keep-log-file-threshold-mb	Log file rotation threshold (in MB)	256
kylin.env.log-rotate-check-cron	Crontab time configuration for log rotation	33 * * * *
kylin.env.log-rotate-enabled	Enable log rotation using crontab	true	false

Default Log Rotation Strategy

To use the default log rotation strategy:

1. Set kylin.env.log-rotate-enabled to true (default).
2. Ensure users running Kylin can use the logrotate and crontab commands to add a scheduled task.

Kylin will:

• Add or update crontab tasks according to kylin.env.log-rotate-check-cron on startup or restart.
• Remove added crontab tasks on exit.

Known Limitations

• If the default log rotation policy conditions are not met, Kylin will only perform log rolling checks at startup. This means that log files will be rotated based on the kylin.env.max-keep-log-file-number and kylin.env.max-keep-log-file-threshold-mb parameters every time the kylin.sh start command is executed. Note that prolonged Kylin runtime may result in excessively large log files.
• Using crontab to control log rotation may result in log loss during rotation if the log file is too large.