1、标准Loops
标准loops可以直接减少task的次数，如下：
[root@zero01 playbook]# vi loops.yaml
---
- hosts: all
gather_facts: False
tasks:
- name: debug loops
debug: msg="name ------> {{ item }}"
with_items:
- one
- two
运行 loops.yaml 如下：
[root@zero01 playbook]# ansible-playbook loops.yaml -l 192.168.79.129 PLAY [all] *********************************************************************************************** TASK [debug loops] ***************************************************************************************
"changed": false,
"item": "one",
"msg": "name ------> one"
}
ok: [192.168.79.129] => (item=two) => {
"changed": false,
"item": "two",
"msg": "name ------> two"
} PLAY RECAP ***********************************************************************************************
192.168.79.129 : ok=1 changed=0 unreachable=0 failed=0
其中with_items的值是python list数据结构，每个task会循环读取list里面的值。with_items后也可以跟python字典，如下：
[root@zero01 playbook]# vi loops.yaml
---
- hosts: all
gather_facts: False
tasks:
- name: debug loops
debug: msg="name ------> {{ item.key }}
value -----> {{ item.value }}"
with_items:
- {key: "one", value: "VALUE1"}
- {key: "one", value: "VALUE2"}
运行 loops.yaml 如下：
[root@zero01 playbook]# ansible-playbook loops.yaml -l 192.168.79.129 PLAY [all] *********************************************************************************************** TASK [debug loops] ***************************************************************************************
ok: [192.168.79.129] => (item={u'key': u'one', u'value': u'VALUE1'}) => {
"changed": false,
"item": {
"key": "one",
"value": "VALUE1"
},
"msg": "name ------> one value -----> VALUE1"
}
ok: [192.168.79.129] => (item={u'key': u'one', u'value': u'VALUE2'}) => {
"changed": false,
"item": {
"key": "one",
"value": "VALUE2"
},
"msg": "name ------> one value -----> VALUE2"
} PLAY RECAP ***********************************************************************************************
192.168.79.129 : ok=1 changed=0 unreachable=0 failed=0
2、嵌套 Loops
嵌套 Loops 也是常见的循环，主要实现一对多或者多对多的合并，如下：
[root@zero01 playbook]# vi loops.yaml
---
- hosts: all
gather_facts: False
tasks:
- name: debug loops
debug: msg="name ------> {{ item[0] }}
value ------> {{ item[1] }}"
with_nested:
- ['A']
- ['a','b','c']
运行如下：
[root@zero01 playbook]# ansible-playbook loops.yaml -l 192.168.79.129 PLAY [all] ******************************************************************************** TASK [debug loops] ************************************************************************
ok: [192.168.79.129] => (item=[u'A', u'a']) => {
"changed": false,
"item": [
"A",
"a"
],
"msg": "name ------> A value ------> a"
}
ok: [192.168.79.129] => (item=[u'A', u'b']) => {
"changed": false,
"item": [
"A",
"b"
],
"msg": "name ------> A value ------> b"
}
ok: [192.168.79.129] => (item=[u'A', u'c']) => {
"changed": false,
"item": [
"A",
"c"
],
"msg": "name ------> A value ------> c"
} PLAY RECAP ********************************************************************************
192.168.79.129 : ok=1 changed=0 unreachable=0 failed=0
类似：
one=['A']
two=['a','b','c']
[i + y for i in one for y in two]
['Aa', 'Ab', 'Ac']