ALM-45426 ClickHouse Service Quantity Quota Usage in ZooKeeper Exceeds the Threshold

Description

The alarm module checks the quota usage of the ClickHouse service in the ZooKeeper every 60 seconds. This alarm is generated when the alarm module detects that the usage exceeds the threshold (90%).

This alarm is cleared when the system detects that the usage is lower than the threshold and the alarm is cleared.

Attribute

Parameters

Impact on the System

After the ZooKeeper quantity quota of the ClickHouse service exceeds the threshold, you cannot perform cluster operations on the ClickHouse service on FusionInsight Manager. As a result, the ClickHouse service cannot be used.

Possible Causes

When table data is created, inserted, or deleted, the ClickHouse creates znodes on ZooKeeper nodes. As the service volume increases, the number of znodes may exceed the configured threshold.

Procedure

Check the number of znodes created by ClickHouse on ZooKeeper.

1. Log in to the host where the ZooKeeper client is located and log in to the ZooKeeper client.

   Switch to the client installation directory.

   Example: cd /opt/client

   Run the following command to configure environment variables:

   source bigdata_env

   Run the following command to authenticate the user (skip this step in common mode):

   kinit Component service user

   Run the following command to log in to the client tool:

   zkCli.sh -server service IP address of the node where the ZooKeeper role instance locates:client port

2. Run the following command to check the quota used by ClickHouse on ZooKeeper and check whether the ratio of the count value of Output stat to the count value of Output quota in the command output is greater than 0.9.
   listquota /clickhouse

   absolute path is /zookeeper/quota/clickhouse
   Output quota for /clickhouse count=200000,bytes=1000000000
   Output stat for /clickhouse count=2667,bytes=60063

   In the preceding information, the count value of Output stat is 2667, and the count value of Output quota is 200000.

   • If yes, go to 4.
   • If no, check whether the alarm is cleared 5 minutes later. If the alarm persists, go to 5.

3. On FusionInsight Manager, choose Cluster > Services > ClickHouse > Configurations > All Configurations, search for the clickhouse.zookeeper.quota.node.count parameter, and change the value of this parameter to twice the count value of Output stat in 2.
4. Restart the ClickHouse instance for which the alarm is generated, and check whether the alarm is cleared 5 minutes later.
   • If yes, no further action is required.
   • If no, perform 4 again, and check whether the alarm is cleared 5 minutes later. If the alarm persists, go to 5.

Collect the fault information.

5. On FusionInsight Manager, choose O&M. In the navigation pane on the left, choose Log > Download.
6. Expand the Service drop-down list, and select ClickHouse for the target cluster.
7. Click in the upper right corner, and set Start Date and End Date for log collection to 1 hour ahead of and after the alarm generation time, respectively. Then, click Download.
8. Contact O&M personnel and provide the collected logs.

Alarm Clearing

This alarm is automatically cleared after the fault is rectified.

Related Information

None