ansible handler
时间: 2023-11-17 17:56:07 浏览: 39
Ansible中的handler是一种特殊的任务,它只有在被通知时才会执行。通常情况下,handler用于在配置文件更改后重新启动服务或重新加载配置。
当一个任务修改了系统状态,但是后续任务需要在该状态改变后才能执行时,就可以使用handler。例如,在修改了Nginx配置文件后,需要重新加载Nginx服务以使更改生效,这时就可以使用handler。
在playbook中,可以使用notify关键字来通知handler执行。例如:
```
- name: restart nginx
service:
name: nginx
state: restarted
notify: reload nginx
- name: reload nginx
service:
name: nginx
state: reloaded
```
在上面的例子中,当restart nginx任务执行完成后,会通知reload nginx任务执行。
相关问题
ansible notify
在Ansible中,`notify`是一个关键字,用于在任务执行过程中通知其他任务执行的情况。当一个任务执行成功或失败时,可以使用`notify`通知其他任务执行相应的操作,比如重启服务或触发其他任务等。
使用`notify`通知其他任务的步骤如下:
1. 在任务中添加`notify`关键字,并指定通知的处理程序(handler)名称,例如:
```
- name: restart apache
service:
name: apache
state: restarted
notify: restart apache handler
```
2. 在任务中定义相应的处理程序,例如:
```
- name: restart apache handler
service:
name: apache
state: restarted
```
在这个例子中,当`restart apache`任务执行成功后,会通知`restart apache handler`处理程序执行重启Apache服务的操作。
在Ansible中,`notify`通常用于在配置文件或软件安装等任务完成后,触发重启或重新加载服务的操作。
ansible handerls
Ansible handlers are a type of task that is triggered only when a task that precedes it in the playbook has made a change. They are used to perform additional actions that are dependent on the success or failure of a task. Handlers are defined separately from tasks and are only executed if the task they are associated with makes a change to the system.
Handlers are useful for tasks that require a change to be made only once, such as restarting a service or updating a configuration file. They can also be used to trigger actions on multiple hosts in a playbook.
To define a handler, use the "handlers" section in an Ansible playbook. Here is an example:
```
handlers:
- name: restart apache
service:
name: apache
state: restarted
```
In this example, the handler is named "restart apache" and it uses the Ansible service module to restart the Apache service. The handler will only be triggered if a task preceding it in the playbook makes a change to the Apache service.
Handlers can also be called explicitly using the "notify" keyword in a task. Here is an example:
```
tasks:
- name: update configuration file
template:
src: config.j2
dest: /etc/myapp.conf
notify: restart apache
```
In this example, the "update configuration file" task will trigger the "restart apache" handler if it makes a change to the configuration file.
Overall, handlers are a powerful feature of Ansible that allow for more precise control over playbook execution and can help prevent unnecessary actions on systems.