17 Oct 2016
最近公司要做运维自动化(工具使用ansible)，但因为前期未统一环境，导致线上机器JAVA_HOME并不统一 于是有了一个需求，如何使用ansible去获取JAVA_HOME？
特别需要注意的是，下面内容中的转义符”\“仅仅是为了兼容语法而存在，实际使用过程中，应该要去掉
# inventory内容 ********************************* [test] 47.90.80.156 ********************************* # 测试yaml文件内容 ********************************* --- - hosts: all remote_user: root tasks: - command: which java register: get_java - debug: var=get_java ********************************* # 执行报错 ansible-playbook -i hosts main.yml PLAY [all] ********************************************************************* TASK [setup] ******************************************************************* ok: [47.90.80.156] TASK [command] ***************************************************************** fatal: [47.90.80.156]: FAILED! => {"changed": true, "cmd": ["which", "java"], "delta": "0:00:00.006982", "end": "2016-10-17 15:17:52.931760", "failed": true, "rc": 1, "start": "2016-10-17 15:17:52.924778", "stderr": "which: no java in (/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin)", "stdout": "", "stdout_lines": [], "warnings": []} NO MORE HOSTS LEFT ************************************************************* [WARNING]: Could not create retry file 'main.retry'. [Errno 2] No such file or directory: '' PLAY RECAP ********************************************************************* 47.90.80.156 : ok=1 changed=0 unreachable=0 failed=1
以上报错，是因为ansible执行task时，host的PATH变量和实际登录host时的PATH不一致造成的
ansible -i hosts test -m setup |grep PATH "PATH": "/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin",
# inventory内容 ********************************* [test] 47.90.80.156 ********************************* # 测试yaml文件内容 ********************************* --- - hosts: all remote_user: root tasks: - command: which java register: get_java environment: PATH: "\{\{ lookup('env', 'PATH') }}" - debug: var=get_java.stdout ********************************* # environment参数可以改变ansible执行task时的环境变量 # register可以把task的执行结果获取到，此处get_java是一个dict，我们只需要stdout即可 # 执行结果 ansible-playbook -i hosts main.yml PLAY [all] ********************************************************************* TASK [setup] ******************************************************************* ok: [47.90.80.156] TASK [command] ***************************************************************** changed: [47.90.80.156] TASK [debug] ******************************************************************* ok: [47.90.80.156] => { "get_java.stdout": "/usr/java/bin/java" } PLAY RECAP ********************************************************************* 47.90.80.156 : ok=3 changed=1 unreachable=0 failed=0
我们之所以要获取JAVA_HOME，为的是需要将此变量写入到每个tomcat的启动脚本中，所以上面获取的结果还需要写入到template中才圆满
# inventory ********************************* [test] 47.90.80.156 ********************************* # 测试yaml文件内容 ********************************* --- - hosts: all remote_user: root tasks: - command: which java register: get_java environment: PATH: "\{\{ lookup('env', 'PATH') }}" - name: copy init script to host template: src='/root/test.sh' dest='/root/tomcat.sh' ********************************* # 模版文件内容/root/test.sh ********************************* JAVA_HOME=$(dirname $(dirname \{\{ get_java.stdout }})) echo $JAVA_HOME ********************************* # dirname命令可以获取文件的路径，详情可man dirname查看 # 执行结果 ansible-playbook -i hosts main.yml PLAY [all] ********************************************************************* TASK [setup] ******************************************************************* ok: [47.90.80.156] TASK [command] ***************************************************************** changed: [47.90.80.156] TASK [copy init script to host] ************************************************ changed: [47.90.80.156] PLAY RECAP ********************************************************************* 47.90.80.156 : ok=3 changed=2 unreachable=0 failed=0
到目标机器上去看一下tomcat.sh文件
sh /root/tomcat.sh /usr/java cat /root/tomcat.sh JAVA_HOME=$(dirname $(dirname /usr/java/bin/java)) echo $JAVA_HOME
至此，我们已经完成了整个使用ansible自动获取host的JAVA_HOME变量的过程