Ansible：如果服务存在则启动角色

Question

我想运行一个角色，但在我想检查程序是否已经安装之前。

我猜我应该使用模块 "service"？在 Ubuntu 中，服务指向 [ ? ] arkeia

我试过了：

  tasks:
    - name: check arkeia
      service: name=arkeia state=started
      register: result

  roles:
    - { role: arkeia, when: result==true }

否则如果无法检查程序是否已安装，我会检查程序文件夹是否存在，然后启动角色。

编辑：

感谢您的快速回答！

我认为我的缺陷是 "when:" 命令。但是如何检查结果是否为假？

我收到以下错误：

> PLAY [all] ******************************************************************** 

GATHERING FACTS *************************************************************** 
ok: [managed-centos]
ok: [managed-ubuntu]
ok: [ansible]

TASK: [arkeia | check arkeia] ************************************************* 
ok: [ansible]
ok: [managed-ubuntu]
ok: [managed-centos]

TASK: [arkeia | create directory] ********************************************* 
skipping: [managed-centos]
skipping: [managed-ubuntu]
changed: [ansible]

TASK: [arkeia | download sources debian] ************************************** 
skipping: [managed-centos]
skipping: [managed-ubuntu]
changed: [ansible]

TASK: [arkeia | download sources cent_os] ************************************* 
skipping: [ansible]
skipping: [managed-ubuntu]
fatal: [managed-centos] => error while evaluating conditional: ansible_os_family == "RedHat" and p.stat.exist == false

TASK: [arkeia | install Arkeia debian] **************************************** 
fatal: [ansible] => error while evaluating conditional: ansible_os_family == "Debian" and p.stat.exist == false
fatal: [managed-ubuntu] => error while evaluating conditional: ansible_os_family == "Debian" and p.stat.exist == false

FATAL: all hosts have already failed -- aborting

PLAY RECAP ******************************************************************** 
           to retry, use: --limit @/home/vagrant/arkeia.retry

ansible                    : ok=4    changed=2    unreachable=1    failed=0   
managed-centos             : ok=2    changed=0    unreachable=1    failed=0   
managed-ubuntu             : ok=2    changed=0    unreachable=1    failed=0

这是我的剧本：

- name: check arkeia
  stat: path=/etc/init.d/arkeia
  register: p

- name: create directory
  file: state=directory path={{ install_directory }}
  when: p.stat.exists == False

- name: download sources debian
  get_url: url={{ arkeia_deb_url }} dest={{ install_directory }}/{{ deb_filename }}
  when: ansible_os_family == "Debian" and p.stat.exists == false

- name: download sources cent_os
  get_url: url={{ arkeia_centos_url }} dest={{ install_directory }}/{{ centos_filename }}
  when: ansible_os_family == "RedHat" and p.stat.exist == false

- name: install Arkeia debian
  sudo: yes
  apt: deb={{ install_directory }}/{{ deb_filename }}
  when: ansible_os_family == "Debian" and p.stat.exist == false

- name: install Arkeia centos
  sudo: yes
  yum: name={{ install_directory }}/{{ centos_filename }}
  when: ansible_os_family == "RedHat" and p.stat.exist == false

调试结果：

TASK: [arkeia | debug msg="{{ p }}"] ****************************************** 
ok: [ansible] => {
    "msg": "{'invocation': {'module_name': u'stat', 'module_args': u'path=/etc/init.d/arkeia'}, 'stat': {'exists': False}, 'changed': False}"
}
ok: [managed-ubuntu] => {
    "msg": "{'invocation': {'module_name': u'stat', 'module_args': u'path=/etc/init.d/arkeia'}, 'stat': {'exists': False}, 'changed': False}"
}
ok: [managed-centos] => {
    "msg": "{'invocation': {'module_name': u'stat', 'module_args': u'path=/etc/init.d/arkeia'}, 'stat': {'uid': 0, 'exists': True, 'woth': False, 'mtime': 1421377097.0, 'inode': 67318822, 'isgid': False, 'size': 1224, 'wgrp': False, 'isuid': False, 'isreg': True, 'pw_name': 'root', 'gid': 0, 'ischr': False, 'wusr': True, 'xoth': True, 'rusr': True, 'nlink': 1, 'issock': False, 'rgrp': True, 'gr_name': 'root', 'path': '/etc/init.d/arkeia', 'xusr': True, 'atime': 1427813706.6750975, 'md5': '52de32627765e8f6e9ff8c5eee7ba232', 'isdir': False, 'ctime': 1427453340.1586156, 'isblk': False, 'xgrp': True, 'dev': 64769, 'roth': True, 'isfifo': False, 'mode': '0755', 'checksum': 'ddd459110d743402d9e18cfe4b3e032faaf54ba1', 'islnk': False}, 'changed': False}"
}

Answer 1

service 模块不允许您获取当前状态。如果服务不存在，模块执行将失败。

您可以运行 shell: service arkeia status 或 shell: ps -eaf | grep -w arkeia 或 check for file's existance with stat

您做错的另一件事是错误地使用了已注册的变量。它的值是一个 dict（或映射），带有像 rc, stdout, stdout_lines, stderr, ... 这样的键。所以例如要使用 stat 模块，您可以这样做：

- stat: path=/etc/init.d/arkeia
  register: p
- debug: msg="/etc/init.d/arkeia exists and is a file"
  when: p.stat.isreg is defined and p.stat.isreg

如果您不知道结果的内容，那么 debug 并打印它以便您知道您正在访问什么：

- name: check arkeia
  service: name=arkeia state=started
  register: result
- debug: msg="result={{ result }}"

Answer 2

解决方案...很简单:)

- name: create directory
  file: state=directory path={{ install_directory }}
  when: p.stat.exists == False

- name: download sources debian
  get_url: url={{ arkeia_deb_url }} dest={{ install_directory }}/{{ deb_filename }}
  when: ansible_os_family == "Debian" and p.stat.**exists** == **f**alse

- name: download sources cent_os
  get_url: url={{ arkeia_centos_url }} dest={{ install_directory }}/{{ centos_filename }}
  when: ansible_os_family == "RedHat" and p.stat.**exist** == **f**alse

用大写 "F" 写 exists and false 并且有效...

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