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组件启动顺序设置

配置文件名为role_command_order.json，位置在自定义服务的根目录下。

该配置文件主要实现功能就是组织各组件启动、安装、停止等执行的顺序，如启动A服务前必须启动B服务，停止B服务前必须停止A服务等。

在服务器位置

role_command_order.json 文件在  /var/lib/ambari-server/resources/common-services 目录的每个服务下面有，每个 Stack  目录下的服务下面也有 role_command_order.json 。相同的配置，Stack 下面的会覆盖全局的。不同的配置，Ambari  会拼接在一起。高版本的 Stack 会继承低版本的配置。相同的也会覆盖，不同的会合并 。

配置文件格式

拿Hbase的配置来举例

{
  "general_deps" : {
    "_comment" : "dependencies for HBase",
    "HBASE_REGIONSERVER-START": ["HBASE_MASTER-START"], # 在启动 HBASE_REGIONSERVER 之前，启动HBASE_MASTER
    "HBASE_SERVICE_CHECK-SERVICE_CHECK": ["HBASE_MASTER-START", "HBASE_REGIONSERVER-START"], # 执行HBASE_SERVICE_CHECK 服务检查前，需要启动HBASE_MASTER和HBASE_REGIONSERVER
    "HBASE_MASTER-STOP": ["HBASE_REGIONSERVER-STOP"], # 在停止HBASE_MASTER服务前，停止HBASE_REGIONSERVER
    "HBASE_MASTER-START": ["NAMENODE-START", "DATANODE-START", "ZOOKEEPER_SERVER-START", "RANGER_USERSYNC-START", "RANGER_KMS_SERVER-START"],
    "PHOENIX_QUERY_SERVER-START": ["HBASE_MASTER-START"]
  }
}

格式如下

{
  "_comment": "Section 1 comment",
  "section_name_1": {
    "_comment": "Section containing role command orders",
    "<DEPENDENT_COMPONENT_1>-<COMMAND>": ["<DEPENDS_ON_COMPONENT_1>-<COMMAND>", "<DEPENDS_ON_COMPONENT_1>-<COMMAND>"],
    "<DEPENDENT_COMPONENT_2>-<COMMAND>": ["<DEPENDS_ON_COMPONENT_3>-<COMMAND>"],
    ...
  },
  "_comment": "Next section comment",
  ...
}

section_name_1 取值

general_deps	Command orders are applied in all situations
namenode_optional_ha	Command orders are applied when HDFS service is installed and JOURNALNODE component exists (HDFS HA is enabled)
optional_glusterfs	Command orders are applied when cluster has instance of GLUSTERFS service
optional_no_glusterfs	Command orders are applied when cluster does not have instance of GLUSTERFS service
resourcemanager_optional_ha	Command orders are applied when YARN service is installed and multiple RESOURCEMANAGER host-components exist (YARN HA is enabled)

<COMMAND>取值

• INSTALL
• UNINSTALL
• START
• RESTART
• STOP
• EXECUTE
• ABORT
• UPGRADE
• SERVICE_CHECK
• CUSTOM_COMMAND
• ACTIONEXECUTE

规则配置样例

"HIVE_METASTORE-START": ["MYSQL_SERVER-START", "NAMENODE-START"]	Start MySQL and NameNode components before starting Hive Metastore
"MAPREDUCE_SERVICE_CHECK-SERVICE_CHECK": ["NODEMANAGER-START", "RESOURCEMANAGER-START"],	MapReduce service check needs ResourceManager and NodeManagers started
"ZOOKEEPER_SERVER-STOP" : ["HBASE_MASTER-STOP", "HBASE_REGIONSERVER-STOP", "METRICS_COLLECTOR-STOP"],	Before stopping ZooKeeper servers, make sure HBase Masters, HBase RegionServers and AMS Metrics Collector are stopped.

验证

配置启动顺序如下：SPARK2_JOBHISTORYSERVER -> BACKEND -> FRONTEND

{
  "general_deps" : {
    "_comment" : "dependencies for DORIS",
    "BACKEND-START": ["SPARK2_JOBHISTORYSERVER-START"],
    "FRONTEND-START": ["BACKEND-START"],
    "DORIS_SERVICE_CHECK-SERVICE_CHECK": ["FRONTEND-START"]
  }
}

没有配置的时候安装完成默认启动顺序如下

单独启动Doirs服务是这样的

将自定义服务更新到服务器上，更新完配置再次安装服务可以看到顺序按照我们设置的运行

单独启动服务发现顺序也按照我们设置的运行

参考资料

https://cwiki.apache.org/confluence/display/AMBARI/How-To+Define+Stacks+and+Services#How-ToDefineStacksandServices-RoleCommandOrder

相关演示代码

https://download.csdn.net/download/zhangshenghang/88917467