ansible - playbook cycle

1. Standard loop

With_items parameters achieved, item will go to polling with_items this array values.
Defined normal_loos.yaml:

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

Results of the:

Of course, it supports key-value pairs ways:
defined normal2_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: "two", value: "VALUE2"}

Results of the:

 

2. Nested Loops

The combined to achieve a plurality of main body of the loop.
Defined nest_loop.yaml:

---
- hosts: all
  gather_facts: False
  tasks:
    - name: debug loops
      debug: msg="name->{{ item[0] }} value->{{ item[1] }}"
      with_nested:
         - ['A']
         - ['a','b','b']

Results of the:

Explanation:
　　with_nested is an array.
　　Item [0] represents the first element of the array, i.e. [ 'A']
　　Item [. 1] indicates that the second element of the array, i.e. [ 'a', 'b ',' b ']
　　then these two elements are circular.

 

3. hash loops

Standard loop support is an array, a list of python is similar.
In fact, the use of a nested loop [{}, {}] This form of the list of sets of dictionary,
the dictionary can directly support the hash loop form, but to follow yaml disguised form.

Definitions: hash_loop.yaml

---
- hosts: all
  gather_facts: Fasle
  vars:
    user:
      kebi:
        name: zhangrongkai
        addr: luotian
      maoxian: 
        name: songlixing
        addr: xiaochang

  tasks:
    - name: debug loops
      debug: msg="name--->{{ item.key }} value--->{{ item.value.name }} addr---{{ item.value.addr }}"
      with_dict: "{{ user }}"

Convert it to the format in python dictionary:

user = {
    "kebi": {
        "name": "zhangrongkai",
        "addr": "luotian"
    },
    "maoxian": {
        "name": "songlixing",
        "addr": "xiaochang"
    }
}

item = user, key = [kebi, maoxian], and then take the attribute value.

Note that: with_dict: "{{user} }"
prior to 2.0, is used in this format: with_dict: user
otherwise an error:

 

4. File Configuration loops

At some point, we need to do something for a certain type of file, this time you can use fileglob this parameter.
By this fileglob able to match the corresponding file, and then can perform a corresponding operation.
Definitions: file_loop.yaml

---
- hosts: all
  tasks:
    - name: debug loops
      debug: msg="filename--->{{ item }}"
      with_fileglob:
        - /tmp/*.py

Results of the:

Within the ansible is actually calling python module glob, then proceed as follows:
　　glob.glob (. "/ Tmp / * Py")

 

The random selection loops

Randomly selecting a value item in the array.
Definitions: random_loop.yaml

---
- hosts: all
  tasks:
     - name: debug loops
       debug: msg="name--->{{ item }}"
       with_random_choice:
         - "test1"
         - "test2"
         - "test3"

Results of the:

In fact, the interior is the use of random python module.

 

6. Analyzing conditions

Sometimes, we need to perform an operation, the operation may fail, we want to try to perform again after 5 seconds,
this operation was repeated five times, if not enough to quit.
Definitions: case_loop.yaml

---
- hosts: all
  tasks:
    - name: debug loops
      shell: cat /etc/hostname
      register: host
      until: host.stdout.startswith("centos")
      retries: 5
      delay: 5

Results of the:

Explanation:
　　name: Debug Loops # task name, nonessential
　　shell: cat / etc / hostname # operation
　　register: host # operating result is assigned to Host
　　an until: host.stdout.startswith ( "CentOS") # established until ...
　　retries: 5 # repeated five times
　　delay: 5 # repeated once every five seconds

if the operation failed, the result is the following:

 

7. Priority documents matching Loops

File priority matches are matched from top to bottom according to your incoming variable or file, if the match to a file, it will be as a value {{item}} with this document.

---
- hosts: all
  tasks:
    - name: debug loops
      debug: msg="file--->{{ item }}"
      with_first_found:
        - "{{ ansible_distribution }}.yaml"
        - "default.yaml

 

8.register Loops

Before receiving the result register defined by shell operations ret.
It was received before a data, but now does receive more.

Definitions: register_loop.yaml

---
- hosts: all
  tasks: 
    - name: debug loops
      shell: "{{ item }}"
      with_items:
        - hostname
        - uname
      register: ret
    - name: display loops
      debug: msg="{% for i in ret.results %} {{ i.stdout }} {% endfor %}"

Results of the: