Starting OmniStateStore

This section describes how to start the OmniStateStore service to enable the acceleration function of Flink state storage.

1. Set the configuration items in the flink-conf.yaml file located in the Flink conf directory based on the service requirements and deployment environment.

   Configuration item format: ${Configuration item name} + ${Colon} + ${Space} + ${Configuration item value}. Configuration Items describes the configuration items. The following describes the configuration items in different scenarios.

   • Add or modify the following configuration items in ${FLINK_HOME}/conf/flink-conf.yaml to enable OmniStateStore. Update the configuration files of the Job Manager and all Task Managers.

     Table 1 Configuration items

     Configuration Item	Description	Example	Remarks
     state.backend	Open-source Flink parameter, which is used to configure the state backend.	com.huawei.ock.bss.OckDBStateBackendFactory	This configuration item determines the state backend type. Verify that the value is case-sensitive and correctly spelled.
     state.backend.ockdb.localdir	Local OmniStateStore state data path.	/usr/local/flink/ockdb	Check that the path exists and the Flink run user has the read and write permissions on the path.
     state.backend.ockdb.jni.logfile	OmniStateStore log path.	/usr/local/flink/log/kv.log	The Flink log path is recommended for this path.

     A configuration example is as follows:

     state.backend: com.huawei.ock.bss.OckDBStateBackendFactory
     state.backend.ockdb.localdir: /usr/local/flink/ockdb
     state.backend.ockdb.jni.logfile: /usr/local/flink/log/kv.log

   • Enable persistent storage of priority queues.

     A configuration example is as follows:

     state.backend.ockdb.timer-service.factory: OCKDB

   • Enable KV separated storage.

     A configuration example is as follows:

     state.backend.ockdb.kv-separate.switch: true
     state.backend.ockdb.kv-separate.threshold: 200

2. Create the necessary directories.
   In the example, state.backend.ockdb.localdir is set to /usr/local/flink/ockdb and state.backend.ockdb.checkpoint.backup is set to /usr/local/flink/checkpoint/backup. Replace the example directories with the actual directories used in your installation.

   mkdir -p /usr/local/flink/ockdb
   mkdir -p /usr/local/flink/checkpoint/backup

3. Start a Flink task and view the configuration items in the log to check whether the configuration is successful.
4. Run the ${FLINK_HOME}/examples/streaming/WordCount.jar demo application.

   If "OmniStateStore service start success" is displayed in the Task Manager logs, OmniStateStore is started successfully.