ALM-18010 Number of Pending Yarn Tasks Exceeds the Threshold (For MRS 2.x or Earlier)

Description

The system checks the number of pending Yarn tasks every 30 seconds and compares the number of tasks with the threshold. This alarm is generated when the number of pending tasks exceeds the threshold.

You can change the threshold by choosing System > Configure Alarm Threshold > Service > Yarn > Queue Root Pending Applications > Queue Root Pending Applications on MRS Manager.

This alarm is cleared when the number of pending tasks is less than or equal to the threshold.

Attribute

Parameters

Impact on the System

Tasks may be stacked and cannot be processed in a timely manner.

Possible Causes

The computing capability of the cluster is lower than the task submission rate. As a result, the task cannot be processed in a timely manner after being submitted.

Procedure

1. Check the usage of memory and vCores on the Yarn page.

   Check whether the values of Memory Used|Memory Total and VCores Used|VCores Total on the native Yarn page reach or approach the maximum values.

   • If yes, go to 2.
   • If no, go to 5.

2. Check the number of submitted tasks.

   Check whether the running tasks are submitted at a normal frequency.

   • If yes, go to 3.
   • If no, go to 5.

3. Scale out the cluster.

   The scale-out is based on the site requirements. For details, see Manually Scaling Out a Cluster.

4. After the scale-out is completed, check whether the alarm is cleared.
   • If yes, no further action is required.
   • If no, go to 5.

5. Collect fault information.
   1. On MRS Manager, choose System > Export Log.
   2. Contact the O&M engineers and send the collected logs.

Reference

None