Ansible - 模块 - shell

概述
1. ansible 的 shell 模块
准别
1. ansible 控制节点
  1. ansible
    1. 2.8.1
2. 远程节点
  1. OS
    1. CentOS 7.5
  2. 无密码登录
    1. 已经打通

1. 模块

概述
1. ansible 功能的具体实现
模块
1. 本质
  1. ansible 携带的功能模块 lib
  2. 不同的模块, 实现了不同的功能
  3. 模块通常的作用
    1. 操作系统资源
    2. 执行系统命令
    3. 操作系统文件
  4. 如果没有理想的模块, 当然可以自己写

2. shell

概述
1. 执行 shell 命令的模块
2. 比较基础
  1. 有些缺点
  2. 建议用 command 模块替代
  3. 但还是值得一讲

1. 基本

概述
1. 最基本的命令

命令1: pwd

命令

# -m 使用的是 shell
# -a 是要被执行的命令
> ansible -i hosts demo -m shell -a 'pwd'

结果
```
demo | CHANGED | rc=0 >>
/root
```
疑问
1. 默认位置
  1. 默认的 pwd, 是默认用户的 home 目录
    1. 默认的用户, 是 root
2. 我想要换目录, 那该怎么办呢?

playbook

# playbook02.yml
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'pwd'
# ansible-playbook -i hosts playbook02.yml
- hosts: servers
  # 关闭 采集
  gather_facts: false
  tasks:
   - name: shell test pwd
     shell: pwd

命令2: 尝试换个目录

命令

> ansible -i hosts demo -m shell -a 'cd /etc'

结果

# 貌似没有任何返回啊...
demo | CHANGED | rc=0 >>

疑问

如果地址输错了, 会怎么样

结果

demo | FAILED | rc=1 >>
/bin/sh: line 0: cd: /etcd: No such file or directorynon-zero return code

playbook

playbook03.yml
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'cd /etc'
# ansible-playbook -i hosts playbook03.yml
- hosts: servers
  gather_facts: false
  tasks:
   - name: shell test cd
     shell: cd /etc

命令3: 换个目录再查看

命令

# ; 可以分割命令
> ansible -i hosts demo -m shell -a 'cd /etc; pwd'

结果
```
demo | CHANGED | rc=0 >>
/etc
```

疑问

如果换目录错了, 会怎么样呢

结果

# 前面的命令报错了, 后面的命令还是在执行
# 这个就有点考验人了
demo | CHANGED | rc=0 >>
/root/bin/sh: line 0: cd: /etcd: No such file or directory

playbook

# 这个 tasks 下面, 有两个 shell 任务
playbook04.yml
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'cd /etc'
# ansible-playbook -i hosts playbook04.yml
- hosts: servers
  gather_facts: false
  tasks:
   - name: shell test cd
     shell: cd /etc

命令4: 另一种换目录的方式

命令

> ansible -i hosts demo -m shell -a 'chdir=/etc pwd'

结果
```
demo | CHANGED | rc=0 >>
/etc
```

playbook

playbook05.yml
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'chdir=/etc pwd'
# ansible-playbook -i hosts playbook05.yml
- hosts: servers
  gather_facts: false
  tasks:
   - name: shell test cd
     shell: cd /etc

疑问

如果换目录错了, 会怎么样呢

结果

# 会有报错, 后面代码不会执行
# 建议使用这种方式来切换目录
demo | FAILED! => {
"ansible_facts": {
    "discovered_interpreter_python": "/usr/bin/python"
},
"changed": false,
"module_stderr": "Shared connection to 192.168.2.xxx closed.\r\n",
"module_stdout": "Traceback (most recent call last):\r\n  File \"/root/.ansible/tmp/ansible-tmp-1569235278.83-13414444200011/AnsiballZ_command.py\", line 114, in <module>\r\n    _ansiballz_main()\r\n  File \"/root/.ansible/tmp/ansible-tmp-1569235278.83-13414444200011/AnsiballZ_command.py\", line 106, in _ansiballz_main\r\n    invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\r\n  File \"/root/.ansible/tmp/ansible-tmp-1569235278.83-13414444200011/AnsiballZ_command.py\", line 49, in invoke_module\r\n    imp.load_module('__main__', mod, module, MOD_DESC)\r\n  File \"/tmp/ansible_command_payload_dCXTDZ/__main__.py\", line 327, in <module>\r\n  File \"/tmp/ansible_command_payload_dCXTDZ/__main__.py\", line 263, in main\r\nOSError: [Errno 2] No such file or directory: '/etcd'\r\n",
"msg": "MODULE FAILURE\nSee stdout/stderr for the exact error",
"rc": 1
}

又有一个新问题
1. 如果可以这样
  1. ansible 发现目录不存在, 就不执行了
    1. 这个真的有

命令6: removes
1. 命令
```
# 如果没有 /etcd, 就不执行命令了
> ansible -i hosts demo -m shell -a 'removes=/etcd pwd'
```
2. 结果
```
demo | SUCCESS | rc=0 >>
skipped, since /etcd does not exist
```
3. playbook
```
playbook06.yml 
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'removes=/etcd pwd'
# ansible-playbook -i hosts playbook06.yml
- hosts: servers
  gather_facts: false
  tasks:
   - name: shell test cd
     shell: cd /etc
     args:
        removes: /etcd
```
4. 疑问
  1. 如果同时使用 removes 和 chdir 两个参数会如何呢
    1. 目录存在
```
> ansible -i hosts demo -m shell -a 'removes=/etcd chdir=/etc pwd'
demo | SUCCESS | rc=0 >>
skipped, since /etcd does not exist
```
    2. 目录不存在
      # 不存在还是会有问题啊... > ansible -i hosts demo -m shell -a 'removes=/etcd chdir=/etcd pwd' demo | FAILED! => { "ansible_facts": { "discovered_interpreter_python": "/usr/bin/python" }, "changed": false, "module_stderr": "Shared connection to 192.168.2.135 closed.\r\n", "module_stdout": "Traceback (most recent call last):\r\n File \"/root/.ansible/tmp/ansible-tmp-1569236237.29-269825187752078/AnsiballZ_command.py\", line 114, in <module>\r\n _ansiballz_main()\r\n File \"/root/.ansible/tmp/ansible-tmp-1569236237.29-269825187752078/AnsiballZ_command.py\", line 106, in _ansiballz_main\r\n invoke_module(zipped_mod, temp_path, ANSIBALLZ_PARAMS)\r\n File \"/root/.ansible/tmp/ansible-tmp-1569236237.29-269825187752078/AnsiballZ_command.py\", line 49, in invoke_module\r\n imp.load_module('__main__', mod, module, MOD_DESC)\r\n File \"/tmp/ansible_command_payload_YsMUPL/__main__.py\", line 327, in <module>\r\n File \"/tmp/ansible_command_payload_YsMUPL/__main__.py\", line 263, in main\r\nOSError: [Errno 2] No such file or directory: '/etcd'\r\n", "msg": "MODULE FAILURE\nSee stdout/stderr for the exact error", "rc": 1 }
  2. 有目录存在不执行的参数吗
    1. 有的

命令7: creates

命令

> ansible -i hosts demo -m shell -a 'creates=/etcd pwd'

结果
```
demo | CHANGED | rc=0 >>
/root
```

playbook

playbook07.yml
---
# 测试 shell
# ansible -i hosts demo -m shell -a 'creates=/etcd pwd'
# ansible-playbook -i hosts playbook07.yml
- hosts: servers
  gather_facts: false
  tasks:
   - name: shell test cd
     shell: cd /etc
     args:
        creates: /etcd

疑问
1. 如果放多个参数, 会是怎么样的关系
  1. 简单试了试, 貌似是与的关系
  2. 想做或操作, 但是我没有找到

其他
1. shell 还有其他的属性, 这里就不在多说了
2. command 模块其实更加适合执行命令, 有更多的有点
3. 如果你使用 shell 命令, 做 rpm 操作时
  1. ansible 会提示使用 yum, dnf 或者 zypper
  2. 其他的模块, 也了解下吧

ps

ref
1. shell – Execute shell commands on targets

Ansible - 模块 - shell

1. 模块

2. shell

1. 基本

ps

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