笔记 | Ansible

### 标准 Loops
#### with_items
标准 Loops 是编写playbook过程中使用最多的一种loops
with_items 的值是 python list 数据结构
- 每个 task 会循环读取 list 里面的值
- key 的名称是 item

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "name ------> {{ item }}"
      with_items:
        - one
        - two
```

运行结果如下所示
```
$ ansible-playbook -i hosts.ini loops.yaml -l clientsrv001
PLAY [all] ************************************************************************************************************************************

PLAY RECAP ************************************************************************************************************************************
clientsrv001               : ok=1    changed=0    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
```

with_items 也支持 python 字典

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "name ------> {{ item.key }} vaule ------> {{ item.vaule }}"
      with_items:
        - {key: 'one', vaule: 'VAULE1'}
        - {key: 'two', vaule: 'VAULE2'}
```

运行结果如下

```
$ ansible-playbook -i hosts.ini loops.yaml -l clientsrv001

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

TASK [debug loops] ****************************************************************************************************************************
ok: [clientsrv001] => (item={u'vaule': u'VAULE1', u'key': u'one'}) => {
    "msg": "name ------> one vaule ------> VAULE1"
}
ok: [clientsrv001] => (item={u'vaule': u'VAULE2', u'key': u'two'}) => {
    "msg": "name ------> two vaule ------> VAULE2"
}

### 嵌套 Loops
#### with_nested
嵌套 Loops 是比较常见的一种循环
主要实现一对多或者多对多的合并

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "name ------> {{ item[0] }} vaule ------> {{ item[1] }}"
      with_nested:
        - ['A', 'B']  # 下标为 0 的值
        - ['a', 'b', 'c']  # 下标为 1 的值
```

运行结果如下

```
$ ansible-playbook -i hosts.ini loops.yaml -l clientsrv001

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

TASK [debug loops] ****************************************************************************************************************************
ok: [clientsrv001] => (item=[u'A', u'a']) => {
    "msg": "name ------> A vaule ------> a"
}
ok: [clientsrv001] => (item=[u'A', u'b']) => {
    "msg": "name ------> A vaule ------> b"
}
ok: [clientsrv001] => (item=[u'A', u'c']) => {
    "msg": "name ------> A vaule ------> c"
}
ok: [clientsrv001] => (item=[u'B', u'a']) => {
    "msg": "name ------> B vaule ------> a"
}
ok: [clientsrv001] => (item=[u'B', u'b']) => {
    "msg": "name ------> B vaule ------> b"
}
ok: [clientsrv001] => (item=[u'B', u'c']) => {
    "msg": "name ------> B vaule ------> c"
}

可以通过一个python的例子来解释这个例子

```python
one = 'A'
two = ['a', 'b', 'c']

print([i + y for i in one for y in two])
```

### 散列 Loops
#### with_dict
散列 Loops 就是变量支持更丰富的数据结构
with_dict 是接收一个python 字典（经过 yaml.load 后）的格式的变量

```yaml
---
- hosts: all
  gather_facts: False

vars:
    user:
      shencan:
        name: shencan
        shell: bash
      ruifengyun:
        name: ruifengyun
        shell: zsh

tasks:
    - name: debug loops
      debug:
        msg: "name ------> {{ item.key }} vaule ------> {{ item.value.name }} ------> shell {{ item.value.shell }}"
      with_dict: "{{ user }}"
```

执行结果如下

```
$ ansible-playbook -i hosts.ini loops.yaml -l clientsrv001

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

TASK [debug loops] ****************************************************************************************************************************
ok: [clientsrv001] => (item={u'key': u'ruifengyun', u'value': {u'shell': u'zsh', u'name': u'ruifengyun'}}) => {
    "msg": "name ------> ruifengyun vaule ------> ruifengyun ------> shell zsh"
}
ok: [clientsrv001] => (item={u'key': u'shencan', u'value': {u'shell': u'bash', u'name': u'shencan'}}) => {
    "msg": "name ------> shencan vaule ------> shencan ------> shell bash"
}

### 文件匹配 Loops
#### with_fileglob
文件匹配 loops 是编写 playbook 的时候需要针对文件进行操作的一种常用循环

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "files ------> {{ item }}"
      with_fileglob:
        - /var/log/*.log
```

文件 loops 就是使用 python glob 模块去做文件模糊匹配的

```python
import glob

print(glob.glob('/var/log/*.log'))
```

### 随机选择 Loops
#### with_random_choice
with_random_choice 就是在传人的 list 中随机选择一个

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "name ------> {{ item }}"
      with_random_choice:
        - one
        - two
        - three
```

### 条件判断 Loops
#### until
如果需要检测这个 task 的结果是否达到了预想的状态，until 可以循环检测
- delay 每次检测停顿几秒
- retries 检测多少次

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      shell:
        cmd: hostname
      register: host
      until: host.stdout.startswith("name")
      retries: 3
      delay: 1
```

### 文件优先级匹配 Loops
#### with_first_found
文件优先匹配会根据你传人的变量或者文件进行从上往下匹配
如果匹配到某个文件，它会用这个文件当作 {{ item }} 的值

```yaml
---
- hosts: all
  gather_facts: False

tasks:
    - name: debug loops
      debug:
        msg: "files ------> {{ item }}"
      with_first_found:
        - "{{ ansible_distribution }}.yaml"
        - loops.yaml
```

### 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

```yaml
---
- hosts: all
  gather_facts: False

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

晓松

playbook 循环

playbook 常见的几种循环

晓松

playbook 循环 playbook 常见的几种循环

playbook 循环

playbook 常见的几种循环