Ansible_处理失败的任务
一、Ansible处理任务失败
1、管理play中任务错误
1️⃣：Ansible评估任务的返回代码，从而确定任务是成功还是失败
2️⃣：通常而言，当任务失败时，Ansible将立即在该主机上中止play的其余部分并且跳过所有后续任务，但有些时候，可能希望即使在任务失败时也继续执行play
2、忽略任务失败
1️⃣：默认情况下，任务失败时play会中止。不过，可以通过忽略失败的任务来覆盖此行为。可以在任务中使用ignore_errors关键字来实现此目的
- 演示实例：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: install httpd yum: name: packages //没有这个包 state: present ignore_errors: yes //可选｛yes、no｝ - name: shoe some massage debug: msg: "hello word" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [install httpd] ****************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"ansible_facts": {"discovered_interpreter_python": "/usr/libexec/platform-python"}, "changed": false, "failures": ["No package packages available."], "msg": "Failed to install some of the specified packages", "rc": 1, "results": []} ...ignoring //已经忽略这个任务出错 TASK [shoe some massage] ************************************************************************************************************************************************** ok: [client.example.com] => { "msg": "hello word" } PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=1
3、任务失败也强制执行处理程序（handlers）
1️⃣：在play中设置force_handlers: yes关键字，则即使play因为后续任务失败而中止也会调用被通知的处理程序（force：促使，推动）
- 演示实例：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all force_handlers: yes //可选｛yes、no｝ tasks: - name: install httpd shell: ls //这条命令一定会执行成功，从而保证handlers处理程序一定会被触发 notify: - massage - name: install httpd yum: name: packages //没有这个包，肯定会出错 state: present handlers: - name: massage debug: msg: "hello word" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [install httpd] ****************************************************************************************************************************************************** changed: [client.example.com] TASK [install httpd] ***************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"changed": false, "failures": ["No package packages available."], "msg": "Failed to install some of the specified packages", "rc": 1, "results": []} RUNNING HANDLER [massage] ************************************************************************************************************************************************* ok: [client.example.com] => { "msg": "hello word" } PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=3 changed=1 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0
2️⃣：处理程序会在任务报告changed结果时获得通知，而在任务报告ok或failed结果时不会获得通知
4、指定任务失败的条件
1️⃣：在任务中使用failed_when关键字来指定表示任务已失败的条件；通常与命令模块搭配使用，这些模块可能成功执行了某一命令，但命令的输出可能指示了失败
- 演示实例一：使用failed_when关键字
//查看使用的脚本 [root@localhost project]# cat files/test.sh #!/bin/bash cat /root //这句肯定会出错 echo "hello word" //注意：在playbook中执行脚本会以最后一个命令作为错误判断标准，中间错误命令不会影响整体的出错，同样也不会因为中间出错而报错 //查看playbook，执行一次看是否成功 [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test script: files/test.sh [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** changed: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0 //这样无法判断是否都执行成功 //添加任务失败判断语句 [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test script: files/test.sh register: result failed_when: "'Is a directory' in result['stdout']" [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"changed": true, "failed_when_result": true, "rc": 0, "stderr": "Shared connection to client.example.com closed.\r\n", "stderr_lines": ["Shared connection to client.example.com closed."], "stdout": "cat: /root: Is a directory\r\nhello word\r\n", "stdout_lines": ["cat: /root: Is a directory", "hello word"]} PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=1 changed=0 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0
2️⃣：fail模块也可用于强制任务失败（主要是将杂乱的提示信息通过自己设置提示方式，达到简单、明了的目的）
- 演示实例二：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test script: files/test.sh register: result - fail: msg: "There have a failed" when: "'Is a directory' in result['stdout']" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** changed: [client.example.com] TASK [fail] *************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"changed": false, "msg": "There have a failed"} PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0
5、指定何时任务报告“changed”结果
1️⃣：当任务对托管主机进行了更改时，会报告 changed 状态并通知处理程序；如果任务不需要进行更改，则会报告ok并且不通知处理程序
2️⃣：使用changed_when关键字可用于控制任务在何时报告它已进行了更改
- 演示实例一：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test shell: echo "hello word" //执行后发现，每次都是changed [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** changed: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0 //添加changed_when关键字，以便报告OK [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test shell: echo "hello word" changed_when: false //可选｛true、false｝ [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** ok: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=0 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0
3️⃣：根据通过已注册变量收集的模块的输出来报告changed
- 演示实例二：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all tasks: - name: test command: echo "hello word" register: result changed_when: "'hello word' in result['stdout']" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [Gathering Facts] **************************************************************************************************************************************************** ok: [client.example.com] TASK [test] *************************************************************************************************************************************************************** changed: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0 //因为在result['stdout']中有hello word ，所以被认定为是true，所以就显示changed
6、Ansible块和错误处理
1️⃣：在playbook中，块是对任务进行逻辑分组的子句，可用于控制任务的执行方式
2️⃣：通过块，也可结合rescue和always语句来处理错误。如果块中的任何任务失败，则执行其rescue块中的任务来进行恢复
3️⃣：在block子句中的任务以及rescue子句中的任务（如果出现故障）运行之后，always子句中的任务运行
4️⃣：总结：
- block：定义要运行的主要任务
- rescue：定义要在block子句中定义的任务失败时运行的任务
- always：定义始终都独立运行的任务，不论block和rescue子句中定义的任务是成功还是失败
5️⃣：演示：
- 演示实例一：当只有block和rescue，且block语句执行成功时，只执行block语句而不执行rescue语句（rescue：营救、救援）
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block shell: echo "hello word" rescue: - name: rescue shell: ls /root //执行play [root@localhost project]# ansible-playbook --syntax-check playbook.yaml playbook: playbook.yaml [root@localhost project]# an anacron ansible-config ansible-console ansible-galaxy ansible-playbook ansible-test ansible ansible-connection ansible-doc ansible-inventory ansible-pull ansible-vault [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** changed: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=1 changed=1 unreachable=0 failed=0 skipped=0 rescued=0 ignored=0 //可以发现，只执行了block语句，并没有执行rescue语句
- 演示实例二：当只有block和rescue，且block语句执行失败时，不执行block语句而执行rescue语句
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block command: cat / //这句肯定会失败 rescue: - name: rescue shell: ls /root //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"ansible_facts": {"discovered_interpreter_python": "/usr/libexec/platform-python"}, "changed": true, "cmd": ["cat", "/"], "delta": "0:00:00.005350", "end": "2020-09-08 10:59:18.381699", "msg": "non-zero return code", "rc": 1, "start": "2020-09-08 10:59:18.376349", "stderr": "cat: /: Is a directory", "stderr_lines": ["cat: /: Is a directory"], "stdout": "", "stdout_lines": []} TASK [rescue] ************************************************************************************************************************************************************* changed: [client.example.com] PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=1 changed=1 unreachable=0 failed=0 skipped=0 rescued=1 ignored=0 //可以看出，block语句执行失败而执行了rescue语句
- 演示实例三：当block语句、rescue语句和always语句都有时，无论block语句是否失败，always语句总是执行
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block command: cat / rescue: - name: rescue shell: ls /root always: - name: always debug: msg: "This is my test" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"ansible_facts": {"discovered_interpreter_python": "/usr/libexec/platform-python"}, "changed": true, "cmd": ["cat", "/"], "delta": "0:00:00.008993", "end": "2020-09-08 11:05:47.816489", "msg": "non-zero return code", "rc": 1, "start": "2020-09-08 11:05:47.807496", "stderr": "cat: /: Is a directory", "stderr_lines": ["cat: /: Is a directory"], "stdout": "", "stdout_lines": []} TASK [rescue] ************************************************************************************************************************************************************* changed: [client.example.com] TASK [always] ************************************************************************************************************************************************************* ok: [client.example.com] => { "msg": "This is my test" } PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=1 ignored=0
6️⃣：block中的when条件也会应用到其rescue和always子句（若存在）
- 演示实例一：
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block command: echo "hello word" //该语句没有错误 when: ansible_facts['distribution'] == "CentOS" //条件判断出错会导致block语句不会执行 rescue: - name: rescue shell: ls /root always: - name: always debug: msg: "This is my test" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"msg": "The conditional check 'ansible_facts['distribution'] == \"CentOS\"' failed. The error was: error while evaluating conditional (ansible_facts['distribution'] == \"CentOS\"): 'dict object' has no attribute 'distribution'\n\nThe error appears to be in '/root/project/playbook.yaml': line 7, column 11, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n block:\n - name: block\n ^ here\n"} TASK [rescue] ************************************************************************************************************************************************************* changed: [client.example.com] TASK [always] ************************************************************************************************************************************************************* ok: [client.example.com] => { "msg": "This is my test" } PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=2 changed=1 unreachable=0 failed=0 skipped=0 rescued=1 ignored=0
- 演示实例二：
实例二//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block command: echo "hello word" when: ansible_facts['distribution'] == "CentOS" rescue: - name: rescue shell: ls /root when: ansible_facts['distribution_major_version'] == "7" //这句when语句会执行失败，导致rescue语句不会执行 always: - name: always debug: msg: "This is my test" //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** fatal: [client.example.com]: FAILED! => {"msg": "The conditional check 'ansible_facts['distribution'] == \"CentOS\"' failed. The error was: error while evaluating conditional (ansible_facts['distribution'] == \"CentOS\"): 'dict object' has no attribute 'distribution'\n\nThe error appears to be in '/root/project/playbook.yaml': line 7, column 11, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n block:\n - name: block\n ^ here\n"} TASK [rescue] ************************************************************************************************************************************************************* fatal: [client.example.com]: FAILED! => {"msg": "The conditional check 'ansible_facts['distribution_major_version'] == \"7\"' failed. The error was: error while evaluating conditional (ansible_facts['distribution_major_version'] == \"7\"): 'dict object' has no attribute 'distribution_major_version'\n\nThe error appears to be in '/root/project/playbook.yaml': line 12, column 11, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n rescue:\n - name: rescue\n ^ here\n"} TASK [always] ************************************************************************************************************************************************************* ok: [client.example.com] => { "msg": "This is my test" } PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=1 changed=0 unreachable=0 failed=1 skipped=0 rescued=1 ignored=0 //可以看出，block语句和rescue语句都没执行
- 演示实例三：
实例三
//查看playbook [root@localhost project]# cat playbook.yaml --- - hosts: all gather_facts: no tasks: - name: test block: - name: block command: echo "hello word" rescue: - name: rescue shell: ls /root always: - name: always debug: msg: "This is my test" when: ansible_facts['distribution_version'] == "8" //when条件储出错没回导致always语句执行失败 //执行play [root@localhost project]# ansible-playbook playbook.yaml PLAY [all] **************************************************************************************************************************************************************** TASK [block] ************************************************************************************************************************************************************** changed: [client.example.com] TASK [always] ************************************************************************************************************************************************************* fatal: [client.example.com]: FAILED! => {"msg": "The conditional check 'ansible_facts['distribution_version'] == \"8\"' failed. The error was: error while evaluating conditional (ansible_facts['distribution_version'] == \"8\"): 'dict object' has no attribute 'distribution_version'\n\nThe error appears to be in '/root/project/playbook.yaml': line 15, column 11, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n always:\n - name: always\n ^ here\n"} PLAY RECAP **************************************************************************************************************************************************************** client.example.com : ok=1 changed=1 unreachable=0 failed=1 skipped=0 rescued=0 ignored=0
- 注意：block执行会成功的话，如果用when条件判断，即使判断条件会成功，但block语句任然会失败，而去执行rescue语句
