tencent cloud

Overview

After modifying the configuration of a component, you need to restart the service for the configuration to take effect. To minimize or avoid the impact of the service restart on your business, restart the service on a rolling basis. For instances with active and standby attributes, standby instances will be restarted first before active instances. Rolling restart takes longer than regular restart.

• Services can be restarted in the console, and rolling restart is selected by default. Note that when rolling restart is disabled, restarting all nodes at the same time may make the service unavailable.
• There are two policies for failure handling when node restart fails: waiting for processing in case of failure or continuing processing in case of single node failure.

Directions

1. Log in to the [EMR console](https://console.tencentcloud.com/emr) and click the **ID/Name** of the target cluster in the cluster list to enter the cluster details page.
   

2. To restart the entire component, select **Operation** > **Restart Service** on the target component block of the **Cluster Service** page, or go to the component details page and select **More** > **Restart All Services** in the top-right corner. To restart a role instance, select **Operation** > **Role Management** on the target component block of the **Cluster Service** page, select the target service role, and click **Restart Service**.
   

• When restarting a service on the component block or component details page, you need to select the target service role, restart method, rolling restart switch status, and failure handling policy.
  If you set Service Role to All, the entire component will be restarted.
  
• When restarting the service on the Role Management page, you only need to select the restart method and failure handling policy.
  

4. The restart methods supported by service components are as follows:

   Component	Service	Restart Mode	Description	Remarks
   HDFS	NameNode	Quick restart mode	It can be restarted by running hadoop-daemon.sh stop | start namenode.	-
   	NameNode	Safe restart mode	For an HA cluster, run `saveNameSpace` on the standby NameNode. Then, restart the component by running hadoop-daemon.sh stop | start namenode. For a non-HA cluster, the quick restart mode is used.	Only rolling restart is supported.
   	DataNode	Default restart mode	It can be restarted by running hadoop-daemon.sh stop | start datanode.	-
   	JournalNode	Default restart mode	It can be restarted by running hadoop-daemon.sh stop | start journalnode.	-
   	zkfc	Default restart mode	It can be restarted by running hadoop-daemon.sh stop | start zkfc.	-
   YARN	ResourceManager	Default restart mode	It can be restarted by running sbin/yarn-daemon.sh stop | start resourcemanager.	Only rolling restart is supported.
   	NodeManager	Default restart mode	It can be restarted by running sbin/yarn-daemon.sh stop | start nodemanager.	-
   	JobHisotryServer	Default restart mode	It can be restarted by running sbin/yarn-daemon.sh stop| start historyserver.	-
   	TimeLineServer	Default restart mode	It can be restarted by running sbin/yarn-daemon.sh stop | start timelineserver.	-
   HBase	HbaseThrift	Default restart mode	It can be restarted by running hbase-daemon.sh stop | start thrift.	-
   	HMaster	Default restart mode	It can be restarted by running hbase-daemon.sh stop | start master.	-
   	HRegionServer	Quick restart mode	It can be restarted by running hbase-daemon.sh stop | start regionserver.	-
   	HRegionServer	Safe restart mode	It can be restarted by running graceful_stop.sh --restart --reload.	-
   Hive	HiveMetaStore	Default restart mode	It can be restarted by running hcat_server.sh stop | strat.	-
   	HiveServer2	Default restart mode	It can be restarted by running hive-daemon.sh stop-h2 | start-h2.	-
   	HiveWebHcat	Default restart mode	It can be restarted by running webhcat_server.sh stop | start.	-
   Presto	PrestoCoordinator	Default restart mode	It can be restarted by running bin/launcher stop | start.	Only rolling restart is supported.
   	PrestoWorker	Default restart mode	It can be restarted by running bin/launcher stop | start.	-
   ZooKeeper	QuorumPeerMain	Default restart mode	It can be restarted by running bin/zkServer.sh stop | start.	-
   Spark	SparkJobHistoryServer	Default restart mode	It can be restarted by running sbin/stop-history-server.sh | sbin/start-history-server.sh.	-
   Hue	Hue	Default restart mode	It can be restarted by running build/env/bin/start.sh and build/env/bin/stop.sh.	-
   Oozie	Oozie	Default restart mode	It can be restarted by running oozied.sh stop | start.	-
   Storm	Nimbus	Default restart mode	It can be restarted by running bin/storm-daemon.sh nimbus stop | start.	-
   	Supervisor	Default restart mode	It can be restarted by running bin/storm-daemon.sh supervisor stop | start.	-
   	LogViewer	Default restart mode	It can be restarted by running bin/storm-daemon.sh nimbus stop | start.	-
   	UI	Default restart mode	It can be restarted by running bin/storm-daemon.sh nimbus stop | start.	-
   Ranger	Ranger	Default restart mode	It can be restarted by running sbin/ranger-daemon.sh stop | start.	-
   Alluxio	AlluxioMaster	Default restart mode	It can be restarted by running bin/alluxio-stop.sh master and bin/alluxio-start.sh master.	-
   	AlluxioWorker	Default restart mode	It can be restarted by running bin/alluxio-stop.sh worker and bin/alluxio-start.sh worker.	-
   Ganglia	Httpd	Default restart mode	It can be restarted by running /sbin/service http stop | start.	-
   	Gmetad	Default restart mode	It can be restarted by running /sbin/service gmetad stop | start.	-
   	Gmond	Default restart mode	It can be restarted by running /sbin/service gmon stop | start.	-