Ansible Playbook Loops循环使用

1. 标准循环（with_items:）

with_items的值是python list数据结构，每个task会循环读取list里面的值，然后key的名称是item，也支持python字典形式

• 实例

---
- hosts: all
  gather_facts: True
  tasks:
   - name: debug loops
     debug: msg="name --------> {{ item }}"
     with_items:
               - one
               - two
               - three

###### 检查yml文件是否正确        ansible-playbook loops.yml --syntax-check
###### [root@codis01 playbooks]# ansible-playbook loops.yml -l 192.168.10.5

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

TASK [Gathering Facts] **********************************************************************************************************************
ok: [192.168.10.5]

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=one) => {
    "item": "one",
    "msg": "name --------> one"
}
ok: [192.168.10.5] => (item=two) => {
    "item": "two",
    "msg": "name --------> two"
}
ok: [192.168.10.5] => (item=three) => {
    "item": "three",
    "msg": "name --------> three"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=2    changed=0    unreachable=0    failed=0

2. 嵌套循环（with_nested:）

嵌套循环主要实现一对多，多对多的合并

• 实例

---
- hosts: all
  gather_facts: True
  tasks:
   - name: debug loops
     debug: msg="name --------> {{ item[0] }}   key-------> {{ item[1] }}"
     with_nested:
               - ['A']
               - ['1','2','3']

###### [root@codis01 playbooks]# ansible-playbook loops-nested.yml -l 192.168.10.5

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

TASK [Gathering Facts] **********************************************************************************************************************
ok: [192.168.10.5]

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=[u'A', u'1']) => {
    "item": [
        "A",
        "1"
    ],
    "msg": "name --------> A   key-------> 1"
}
ok: [192.168.10.5] => (item=[u'A', u'2']) => {
    "item": [
        "A",
        "2"
    ],
    "msg": "name --------> A   key-------> 2"
}
ok: [192.168.10.5] => (item=[u'A', u'3']) => {
    "item": [
        "A",
        "3"
    ],
    "msg": "name --------> A   key-------> 3"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=2    changed=0    unreachable=0    failed=0

3. 散列循环（with_dict:）

散列loops相比标准loops就是变量支持更丰富的数据结构，支持YAML格式的数据变量

• 实例

---
- hosts: all
  gather_facts: False
  vars:
    user:
      fengct:
        name: fengct
        shell: bash
      test:
        name: test
        shell: sh
  tasks:
   - name: debug loops
     debug: msg="name --------> {{ item.key }}   keys -------> {{ item.value.name }}   shell -------> {{ item.value.shell }}"
     with_dict: "{{ user }}"

[root@codis01 playbooks] ansible-playbook loops-dict.yml -l 192.168.10.5

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

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item={'key': u'test', 'value': {u'shell': u'sh', u'name': u'test'}}) => {
    "item": {
        "key": "test",
        "value": {
            "name": "test",
            "shell": "sh"
        }
    },
    "msg": "name --------> test   keys -------> test   shell -------> sh"
}
ok: [192.168.10.5] => (item={'key': u'fengct', 'value': {u'shell': u'bash', u'name': u'fengct'}}) => {
    "item": {
        "key": "fengct",
        "value": {
            "name": "fengct",
            "shell": "bash"
        }
    },
    "msg": "name --------> fengct   keys -------> fengct   shell -------> bash"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=1    changed=0    unreachable=0    failed=0

4. 文件匹配循环（with_fileglob:）

• 实例

---
- hosts: all
  gather_facts: False
  tasks:
   - name: debug loops
     debug: msg="YAML files ---------> {{ item }}"
     with_fileglob:
        - /var/log/*.log

###### [root@codis01 playbooks]# ansible-playbook loops-fileglob.yml -l 192.168.10.5

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

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=/var/log/boot.log) => {
    "item": "/var/log/boot.log",
    "msg": "YAML files ---------> /var/log/boot.log"
}
ok: [192.168.10.5] => (item=/var/log/yum.log) => {
    "item": "/var/log/yum.log",
    "msg": "YAML files ---------> /var/log/yum.log"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=1    changed=0    unreachable=0    failed=0

5. 随机选择循环（with_random_choice:）

• 实例

---
- hosts: all
  gather_facts: False
  tasks:
   - name: debug loops
     debug: msg="name --------> {{ item }}"
     with_random_choice:
               - one
               - two
               - three

###### [root@codis01 playbooks]# ansible-playbook loops-random_choice.yml -l 192.168.10.5

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

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=one) => {
    "item": "one",
    "msg": "name --------> one"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=1    changed=0    unreachable=0    failed=0

###### [root@codis01 playbooks]# ansible-playbook loops-random_choice.yml -l 192.168.10.5

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

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=three) => {
    "item": "three",
    "msg": "name --------> three"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=1    changed=0    unreachable=0    failed=0

6. 条件判断Loops（until:）

每5s执行一次cat /root/ansible，然后将结果交给register的host参数，然后判断host.stdout.startswith的内容是否是cat字符串开头，如果条件成立，此task运行完成，如果条件不成立5s后重试，5次还不成立，此task运行失败。这里选用的目录就是一个假目录，所以最后执行结果会是失败的

• 实例

---
- hosts: all
  gather_facts: True
  tasks:
   - name: debug loops
     shell: cat /root/ansible
     register: host
     until: host.stdout.startswith("name")
     retries: 5
     delay: 5

###### [root@codis01 playbooks]# ansible-playbook loops-until.yml -l 192.168.10.5

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

TASK [Gathering Facts] **********************************************************************************************************************
ok: [192.168.10.5]

TASK [debug loops] **************************************************************************************************************************
FAILED - RETRYING: debug loops (5 retries left).
FAILED - RETRYING: debug loops (4 retries left).
FAILED - RETRYING: debug loops (3 retries left).
FAILED - RETRYING: debug loops (2 retries left).
FAILED - RETRYING: debug loops (1 retries left).
fatal: [192.168.10.5]: FAILED! => {"attempts": 5, "changed": true, "cmd": "cat /root/ansible", "delta": "0:00:00.004363", "end": "2018-01-10 03:43:32.985193", "failed": true, "msg": "non-zero return code", "rc": 1, "start": "2018-01-10 03:43:32.980830", "stderr": "cat: /root/ansible: 没有那个文件或目录", "stderr_lines": ["cat: /root/ansible: 没有那个文件或目录"], "stdout": "", "stdout_lines": []}
        to retry, use: --limit @/etc/ansible/playbooks/loops-until.retry

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=1    changed=0    unreachable=0    failed=1

7. 文件优先匹配Loops（with_first_found:）

如果你想引用一个文件，而该文件是从一组文件中根据给定条件匹配出来的，可以使用这种模式

• 实例

---
- hosts: all
  gather_facts: True
  tasks:
   - name: debug loops
     debug: msg="YAML files --------> {{ item }}"
     with_first_found:
       - "{{ ansible_distribution }}.yml"
       - "loops.yml"

###### [root@codis01 playbooks]# ansible-playbook loops-first_found.yml -l 192.168.10.5

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

TASK [Gathering Facts] **********************************************************************************************************************
ok: [192.168.10.5]

TASK [debug loops] **************************************************************************************************************************
ok: [192.168.10.5] => (item=/etc/ansible/playbooks/loops.yml) => {
    "item": "/etc/ansible/playbooks/loops.yml",
    "msg": "YAML files --------> /etc/ansible/playbooks/loops.yml"
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=2    changed=0    unreachable=0    failed=0

8. register loops （with_random_choice:）

register适用于task直接互相传递数据的，一般我们会把register用在单一的task中进行变量临时存储，其实register还可以同时接受多个task的结果当做变量临时存储

• 实例

---
- hosts: all
 gather_facts: True
 tasks:
   - name: debug loops
     shell: "{{ item }}"
     with_items:
       - date
       - hostname
       - uname
     register: num
   - name: SYSTEM INFO LOOPS----------->
     debug: msg="{% for i in num.results %} {{ i.stdout }} {% endfor %}"

###### [root@codis01 playbooks]# ansible-playbook loops-register.yml -l 192.168.10.5

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

TASK [Gathering Facts] **********************************************************************************************************************
ok: [192.168.10.5]

TASK [debug loops] **************************************************************************************************************************
changed: [192.168.10.5] => (item=date)
changed: [192.168.10.5] => (item=hostname)
changed: [192.168.10.5] => (item=uname)

TASK [SYSTEM INFO LOOPS----------->] ********************************************************************************************************
ok: [192.168.10.5] => {
   "msg": " 2018年 01月 10日 星期三 03:50:28 UTC  codis01  Linux "
}

PLAY RECAP **********************************************************************************************************************************
192.168.10.5               : ok=3    changed=1    unreachable=0    failed=0