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官网：
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=38571133
栈的定义可以在源代码树中找到/ambari-server/src/main/resources/stacks。当你安装Ambari Server服务之后，栈的定义可以被发现/var/lib/ambari-server/resources/stacks。
一个栈的结构定义如下
|_ stacks |_ <stack_name> |_ <stack_version> metainfo.xml |_ hooks |_ repos repoinfo.xml |_ services |_ <service_name> metainfo.xml metrics.json |_ configuration {configuration files} |_ package {files, scripts, templates}
在service里的metainfo.xml文件描述这个服务，服务的组件和管理脚本用于执行命令。一个组件的服务可以是MASTER,SLAVE或CLIENT类别。这个<category>告诉Ambari默认命令应该用于管理和监控组件。为每个组件指定< commandScript >执行命令时使用。有一个默认命令定义组件必须支持。
Ambari支持不同的命令脚本用PYTHON编写的。类型是用来知道如何执行命令脚本。你也可以创建自定义命令除了default lifecycle commands之外你的组件需要去支持。
例如，YARN Service描述ResourceManager组件配置metainfo.xml如下：
<component> <name>RESOURCEMANAGER</name> <category>MASTER</category> <commandScript> <script>scripts/resourcemanager.py</script> <scriptType>PYTHON</scriptType> <timeout>600</timeout> </commandScript> <customCommands> <customCommand> <name>DECOMMISSION</name> <commandScript> <script>scripts/resourcemanager.py</script> <scriptType>PYTHON</scriptType> <timeout>600</timeout> </commandScript> </customCommand> </customCommands> </component>
ResourceManager是一个MASTER组件，并且命令脚本是scripts/resourcemanager.py，可以被找到services/YARN/package目录，PYTHON命令脚本,脚本作为PYTHON方法实现default lifecycle commands。这是默认的安装方法安装命令：
class Resourcemanager(Script): def install(self, env): self.install_packages(env) self.configure(env)
你也可以看到一个自定义的命令定义DECOMMISSION,这意味着还有一个DECOMMISSION方法在python命令脚本:
def decommission(self, env): import params ... Execute(yarn_refresh_cmd, user=yarn_user ) pass
栈可以扩展其他堆栈为了分享命令脚本和配置。这样可以减少重复的代码在栈使用以下：
·为子栈定义存储库
·在子栈添加新的服务（不是在父栈）
·覆盖父服务命令脚本
·覆盖父服务的配置
在本例中,我们将创建一个名为“SAMPLESRV”的定制服务,将其添加到现有的栈的定义。
此服务包括MASTER，SLAVE，CLIENT组件。
创建并且添加服务
1.Ambari Server上，浏览到/var/lib/ambari-server/resources/stacks/HDP/2.0.6/services这个目录。在这种情况下，我们将浏览到HDP 2.0的定义。
cd /var/lib/ambari-server/resources/stacks/HDP/2.0.6/services
2.创建一个目录/var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV将包含SAMPLESRV的服务定义。
mkdir /var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV
cd /var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV
3.浏览到新创建的SAMPLESRV目录，创建一个metainfo.xml文件去描述一个新的服务。例如：
<?xml version="1.0"?> <metainfo> <schemaVersion>2.0</schemaVersion> <services> <service> <name>SAMPLESRV</name> <displayName>New Sample Service</displayName> <comment>A New Sample Service</comment> <version>1.0.0</version> <components> <component> <name>SAMPLESRV_MASTER</name> <displayName>Sample Srv Master</displayName> <category>MASTER</category> <cardinality>1</cardinality> <commandScript> <script>scripts/master.py</script> <scriptType>PYTHON</scriptType> <timeout>600</timeout> </commandScript> </component> <component> <name>SAMPLESRV_SLAVE</name> <displayName>Sample Srv Slave</displayName> <category>SLAVE</category> <cardinality>1+</cardinality> <commandScript> <script>scripts/slave.py</script> <scriptType>PYTHON</scriptType> <timeout>600</timeout> </commandScript> </component> <component> <name>SAMPLESRV_CLIENT</name> <displayName>Sample Srv Client</displayName> <category>CLIENT</category> <cardinality>1+</cardinality> <commandScript> <script>scripts/sample_client.py</script> <scriptType>PYTHON</scriptType> <timeout>600</timeout> </commandScript> </component> </components> <osSpecifics> <osSpecific> <osFamily>any</osFamily> <!-- note: use osType rather than osFamily for Ambari 1.5.0 and 1.5.1 --> </osSpecific> </osSpecifics> </service> </services> </metainfo>
4.在上面，我的服务名是"SAMPLESRV"它包含：
·一个MASTER组件“SAMPLESRV_MASTER”
·一个SLAVE组件“SAMPLESRV_SLAVE”
·一个CLIENT组件“SAMPLESRV_CLIENT”
5.接下来，我们创建命令脚本。为命令脚本创建一个目录/var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV/package/scripts我们制定的服务metainfo
1 mkdir -p /var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV/package/scripts 2 cd /var/lib/ambari-server/resources/stacks/HDP/2.0.6/services/SAMPLESRV/package/scripts
6.进入目录并创建.py的命令脚本文件。
例如master.py文件：
import sys from resource_management import * class Master(Script): def install(self, env): print ‘Install the Sample Srv Master‘; def stop(self, env): print ‘Stop the Sample Srv Master‘; def start(self, env): print ‘Start the Sample Srv Master‘; def status(self, env): print ‘Status of the Sample Srv Master‘; def configure(self, env): print ‘Configure the Sample Srv Master‘; if __name__ == "__main__": Master().execute()
例如slave.py文件：
import sys from resource_management import * class Slave(Script): def install(self, env): print ‘Install the Sample Srv Slave‘; def stop(self, env): print ‘Stop the Sample Srv Slave‘; def start(self, env): print ‘Start the Sample Srv Slave‘; def status(self, env): print ‘Status of the Sample Srv Slave‘; def configure(self, env): print ‘Configure the Sample Srv Slave‘; if __name__ == "__main__": Slave().execute()
例如sample_client.py文件：
import sys from resource_management import * class SampleClient(Script): def install(self, env): print ‘Install the Sample Srv Client‘; def configure(self, env): print ‘Configure the Sample Srv Client‘; if __name__ == "__main__": SampleClient().execute()
7.重启Ambari Server
ambari-server restart
参考网址：
https://cwiki.apache.org/confluence/pages/viewpage.action?pageId=38571133
https://github.com/Symantec/ambari-cassandra-service
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原文地址：http://www.cnblogs.com/womars/p/5767966.html
