百度了一下handlers force_handlers的用法,几乎很多文章都是这样描述的:
Handlers只有在其所在的任务被执行时,才会被运行;如果一个任务中定义了notify调用Handlers,但是由于条件判断等原因,该任务未被执行,那么Handlers同样不会被执行。
Handlers只会在每一个play的末尾运行一次;如果想在一个playbook中间运行Handlers,则需要使用meta模块来实现。例如: -meta: flush_handlers.
如果一个play在运行到调用Handlers的语句之前失败了,那么这个Handlers将不会被执行。我们可以使用meta模块的--force-handlers选项来强制执行Handlers,即使Handlers所在的play中途运行失败也能执行。
于是乎就实际操作使用了一下handlers,做出如下总结:
1. 最简单的ansible handlers
1.1 playbook
# cat handlers_sample.yaml
---
- hosts: 127.0.0.1
handlers:
- name: echo handlers
shell: echo "handlers"
tasks:
- name: 输出 test1
shell: echo "test1"
notify:
- echo handlers
- name: 输出test2
shell: echo "test2"
- name: 输出test3
shell: echo "test3"
#
1.2 执行结果
# ansible-playbook -v handlers_sample.yaml Using /etc/ansible/ansible.cfg as config file PLAY [127.0.0.1] *************************************************************************************************************************************************************************** TASK [Gathering Facts] ********************************************************************************************************************************************************************* ok: [127.0.0.1] TASK [输出 test1] **************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test1"", "delta": "0:00:00.002695", "end": "2019-05-25 02:22:36.625148", "rc": 0, "start": "2019-05-25 02:22:36.622453", "stderr": "", "stderr_lines": [], "stdout": "test1", "stdout_lines": ["test1"]} TASK [输出test2] ***************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test2"", "delta": "0:00:00.002935", "end": "2019-05-25 02:22:36.898646", "rc": 0, "start": "2019-05-25 02:22:36.895711", "stderr": "", "stderr_lines": [], "stdout": "test2", "stdout_lines": ["test2"]} TASK [输出test3] ***************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test3"", "delta": "0:00:00.002666", "end": "2019-05-25 02:22:37.141926", "rc": 0, "start": "2019-05-25 02:22:37.139260", "stderr": "", "stderr_lines": [], "stdout": "test3", "stdout_lines": ["test3"]} RUNNING HANDLER [echo handlers] ************************************************************************************************************************************************************ changed: [127.0.0.1] => {"changed": true, "cmd": "echo "handlers"", "delta": "0:00:00.002762", "end": "2019-05-25 02:22:37.401675", "rc": 0, "start": "2019-05-25 02:22:37.398913", "stderr": "", "stderr_lines": [], "stdout": "handlers", "stdout_lines": ["handlers"]} PLAY RECAP ********************************************************************************************************************************************************************************* 127.0.0.1 : ok=5 changed=4 unreachable=0 failed=0 #
可以发现,输出的结果为: test1 test2 test3 handlers ,
2. ansible使用flush_handlers 在中间执行
注意要点: 1. 在使用flush_handlers之后,ansible会就此从后往上执行flush 之前的 handlers
例如如下playbook应该执行输出顺序为: test5 ——> test1 ——> handlers ——> handlers2 ——> test2 ——> test3 ——> handler3
2.1 playbook
# cat handlers_flush_handlers_sample.yaml
---
- hosts: 127.0.0.1
handlers:
- name: echo handlers
shell: echo "handlers"
- name: echo handlers2
shell: echo "handlers2"
- name: echo handlers3
shell: echo "handlers3"
tasks:
- name: 输出 test1
shell: echo "test5"
notify:
- echo handlers2
- name: 输出 test1
shell: echo "test1"
notify:
- echo handlers
- name: 调用meta模块的flush_handlers
meta: flush_handlers
- name: 输出test2
shell: echo "test2"
- name: 输出test3
shell: echo "test3"
notify:
- echo handlers3
#
2.2 执行结果
# ansible-playbook handlers_flush_handlers_sample.yaml -v Using /etc/ansible/ansible.cfg as config file PLAY [127.0.0.1] *************************************************************************************************************************************************************************** TASK [Gathering Facts] ********************************************************************************************************************************************************************* ok: [127.0.0.1] TASK [输出 test1] **************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test5"", "delta": "0:00:00.003382", "end": "2019-05-25 02:43:14.970005", "rc": 0, "start": "2019-05-25 02:43:14.966623", "stderr": "", "stderr_lines": [], "stdout": "test5", "stdout_lines": ["test5"]} TASK [输出 test1] **************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test1"", "delta": "0:00:00.002981", "end": "2019-05-25 02:43:15.211020", "rc": 0, "start": "2019-05-25 02:43:15.208039", "stderr": "", "stderr_lines": [], "stdout": "test1", "stdout_lines": ["test1"]} RUNNING HANDLER [echo handlers] ************************************************************************************************************************************************************ changed: [127.0.0.1] => {"changed": true, "cmd": "echo "handlers"", "delta": "0:00:00.003637", "end": "2019-05-25 02:43:15.451007", "rc": 0, "start": "2019-05-25 02:43:15.447370", "stderr": "", "stderr_lines": [], "stdout": "handlers", "stdout_lines": ["handlers"]} RUNNING HANDLER [echo handlers2] *********************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "handlers2"", "delta": "0:00:00.003179", "end": "2019-05-25 02:43:15.687635", "rc": 0, "start": "2019-05-25 02:43:15.684456", "stderr": "", "stderr_lines": [], "stdout": "handlers2", "stdout_lines": ["handlers2"]} TASK [输出test2] ***************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test2"", "delta": "0:00:00.003304", "end": "2019-05-25 02:43:15.923582", "rc": 0, "start": "2019-05-25 02:43:15.920278", "stderr": "", "stderr_lines": [], "stdout": "test2", "stdout_lines": ["test2"]} TASK [输出test3] ***************************************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test3"", "delta": "0:00:00.002604", "end": "2019-05-25 02:43:16.160683", "rc": 0, "start": "2019-05-25 02:43:16.158079", "stderr": "", "stderr_lines": [], "stdout": "test3", "stdout_lines": ["test3"]} RUNNING HANDLER [echo handlers3] *********************************************************************************************************************************************************** changed: [127.0.0.1] => {"changed": true, "cmd": "echo "handlers3"", "delta": "0:00:00.004195", "end": "2019-05-25 02:43:16.405100", "rc": 0, "start": "2019-05-25 02:43:16.400905", "stderr": "", "stderr_lines": [], "stdout": "handlers3", "stdout_lines": ["handlers3"]} PLAY RECAP ********************************************************************************************************************************************************************************* 127.0.0.1 : ok=8 changed=7 unreachable=0 failed=0 #
3. ansible force-handlers
注意要点: force-handlers主要针对即使playbook执行失败,也要执行代码块成功了的handlers,如果代码块本身执行失败,那么它所对应的handlers应当不会被执行
例如如下playbook应当执行的顺序为: test5 ——> test1(报错)——>handler2
3.1 playbook
# cat handlers_force.yaml
---
- hosts: 127.0.0.1
handlers:
- name: echo handlers
shell: echo "handlers"
- name: echo handlers2
shell: echo "handlers2"
- name: echo handlers3
shell: echo "handlers3"
tasks:
- name: 输出 test1
shell: echo "test5"
notify:
- echo handlers2
- name: 输出 test1
shell: echo1 "test1"
notify:
- echo handlers
- name: 输出test2
shell: echo "test2"
- name: 输出test3
shell: echo "test3"
notify:
- echo handlers3
#
3.2 执行结果
# ansible-playbook -v handlers_force.yaml --force-handlers
Using /etc/ansible/ansible.cfg as config file
PLAY [127.0.0.1] ***************************************************************************************************************************************************************************
TASK [Gathering Facts] *********************************************************************************************************************************************************************
ok: [127.0.0.1]
TASK [输出 test1] ****************************************************************************************************************************************************************************
changed: [127.0.0.1] => {"changed": true, "cmd": "echo "test5"", "delta": "0:00:00.002600", "end": "2019-05-25 02:59:14.348115", "rc": 0, "start": "2019-05-25 02:59:14.345515", "stderr": "", "stderr_lines": [], "stdout": "test5", "stdout_lines": ["test5"]}
TASK [输出 test1] ****************************************************************************************************************************************************************************
fatal: [127.0.0.1]: FAILED! => {"changed": true, "cmd": "echo1 "test1"", "delta": "0:00:00.002676", "end": "2019-05-25 02:59:14.584181", "msg": "non-zero return code", "rc": 127, "start": "2019-05-25 02:59:14.581505", "stderr": "/bin/sh: echo1: command not found", "stderr_lines": ["/bin/sh: echo1: command not found"], "stdout": "", "stdout_lines": []}
RUNNING HANDLER [echo handlers2] ***********************************************************************************************************************************************************
changed: [127.0.0.1] => {"changed": true, "cmd": "echo "handlers2"", "delta": "0:00:00.002615", "end": "2019-05-25 02:59:14.821083", "rc": 0, "start": "2019-05-25 02:59:14.818468", "stderr": "", "stderr_lines": [], "stdout": "handlers2", "stdout_lines": ["handlers2"]}
to retry, use: --limit @/root/ansible/playbook/handlers/handlers_force.retry
PLAY RECAP *********************************************************************************************************************************************************************************
127.0.0.1 : ok=3 changed=2 unreachable=0 failed=1
#
关于ansible handlers,就暂时学习到这儿,路漫漫其修远兮,吾将上下而求索