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
- name: test
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
- name: test
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- hosts: all
tasks:
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: resultfail:
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- name: test
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
- name: test
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- name: test
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
- name: block
//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.yamlPLAY [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
- name: block
//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"
- name: block
//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"
- name: block
//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：
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//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"
- name: block
//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语句都没执行实例二
演示实例三：
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//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
- name: block
//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实例三
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
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