ALM-45637 FlinkServer Task Is Continuously Under Back Pressure

Alarm Description

The system checks the back pressure duration of FlinkServer tasks based on the configured alarm checking interval. This alarm is generated when the back pressure duration of a FlinkServer task reaches the configured threshold. This alarm is cleared when the task back pressure is recovered or the job is successfully restarted.

Alarm Attributes

Alarm Parameters

Impact on the System

Continuous back pressure of Flink jobs may cause performance problems or checkpoint failures. Flink jobs fail. You need to check the status and logs of the Flink jobs to locate the cause. This is a job-level alarm and has no impact on FlinkServer.

Possible Causes

You can view the causes in the specific logs.

Handling Procedure

1. Log in to Manager as a user who has the FlinkServer management permission.
2. Choose Cluster > Services > Yarn and click the link next to ResourceManager WebUI to go to the Yarn page.
3. Locate the failed job based on its name displayed in Location, search for and record the application ID of the failed job, and check whether the job logs are available on the Yarn page.
   Figure 1 Application ID of a job
   

   If yes, go to 4.

   If no, go to 6.

4. Click the application ID of the failed job to go to the job page.
   1. Click Logs in the Logs column to view JobManager logs.
      Figure 2 Clicking Logs
      
   2. Click the ID in the Attempt ID column and click Logs in the Logs column to view TaskManager logs.
      Figure 3 Clicking the ID in the Attempt ID column
      
      Figure 4 Clicking Logs
      
      

      You can also log in to Manager as a user who has the FlinkServer management permission, choose Cluster > Services > Flink, click the link next to Flink WebUI. On the displayed Flink web UI, click Job Management and choose More > Job Monitoring in the Operation column to view the TaskManager logs.

5. View the logs of the failed job to rectify the fault, or contact the O&M personnel personnel and send the collected fault logs. No further action is required.

If logs are unavailable on the Yarn page, download logs from HDFS.

6. On Manager, choose Cluster > Services > HDFS, click the link next to NameNode WebUI to go to the HDFS page, select Utilities > Browse the file system, and download logs in the /tmp/logs/User name/logs/Application ID of the failed job directory.
7. View the logs of the failed job to rectify the fault, or contact the O&M personnel personnel and send the collected fault logs.

Alarm Clearance

This alarm is cleared when FlinkServer task back pressure is recovered or the job is successfully restarted.

Related Information

None