When INFO logs don't reveal enough detail to diagnose a problem, switch to DEBUG to capture finer-grained system state — without restarting the job.
DEBUG logging can affect job performance. Switch back to INFO as soon as you finish troubleshooting.
Log levels
The following log levels are supported, listed in ascending order of urgency.
| Level | Description |
|---|---|
| TRACE | Records finer-grained information than DEBUG logs |
| DEBUG | Records the status of the system |
| INFO | Records important information or information of interest |
| WARN | Records information about potential issues |
| ERROR | Records information about errors and exceptions |
Behavior and limits
Log level scope:
You can only change the log level to INFO or DEBUG. Setting a higher level may hide the information you need.
You can change the log level of the JobManager.
You can change the log level of only one TaskManager at a time. You cannot change the log levels of all TaskManagers at a time. To change the log level of all TaskManagers, change each one separately.
Log visibility after a change:
Changing to DEBUG displays logs at the DEBUG, INFO, WARN, and ERROR levels.
Changing to INFO displays logs at the INFO, WARN, and ERROR levels only.
Only new logs generated after the change are affected. Existing logs are not affected.
Prerequisites
Before you begin, ensure that you have access to the Realtime Compute for Apache Flink console.
Change the log level
Change the JobManager log level
Log on to the Realtime Compute for Apache Flink console.
Click Console in the Actions column of the target workspace.
In the left-side navigation pane, click O&M > Deployments.
On the Deployments page, click the target deployment name.
Click the Logs tab.
In the left-side pane, click the Logs tab and select the running job from the Job drop-down list.
On the Job Manager tab, click the Logs tab.
Click Edit.
In the message that appears, click OK.
From the Log Level drop-down list, select the log level.
Click Confirm.
Change a TaskManager log level
Complete steps 1–6 in Change the JobManager log level.
On the Running Task Managers tab, click the value in the Path, ID column.
Click the Logs tab.
Click Edit.
In the message that appears, click OK.
From the Log Level drop-down list, select the log level.
Click Confirm.
After changing the log level
After switching to DEBUG, monitor the new logs to identify the issue. Once troubleshooting is complete, set the log level back to INFO to restore normal performance.