How to create basic nested loop in ansible playbook?

How to create basic nested loop in ansible playbook?

In Ansible, you can create nested loops using the with_nested keyword. Here’s an example of how to create a basic nested loop in an Ansible playbook:

Example:1

- name: Example of a nested loop
  hosts: all
  vars:
    outer_list:
      - item1
      - item2
    inner_list:
      - subitem1
      - subitem2
  tasks:
    - name: Print outer and inner loop values
      debug:
        msg: "{{ outer_item }} {{ inner_item }}"
      with_nested:
        - "{{ outer_list }}"
        - "{{ inner_list }}"

In this example, we define two lists – outer_list and inner_list. We then use the with_nested keyword to create a nested loop over these two lists. The outer_item and inner_item variables are defined within the loop and are used in the debug module to print out the current values of both variables.

When you run this playbook, Ansible will iterate over each item in the outer_list, and for each item in the outer_list, it will iterate over each item in the inner_list. This will result in a total of four iterations, with the debug module printing out the following output:

ok: [localhost] => (item=['item1', 'subitem1']) => {
    "msg": "item1 subitem1"
}
ok: [localhost] => (item=['item1', 'subitem2']) => {
    "msg": "item1 subitem2"
}
ok: [localhost] => (item=['item2', 'subitem1']) => {
    "msg": "item2 subitem1"
}
ok: [localhost] => (item=['item2', 'subitem2']) => {
    "msg": "item2 subitem2"
}

Example:2

Create a ansible config file as ansible.cfg file in your project directory:

[defaults]
inventory = hosts

Create a hosts file as hosts in the project directory

[webservers]

ansnode1 ansible_ssh_host=192.168.56.202 ansible_python_interpreter=/usr/bin/python

ansnode2 ansible_ssh_host=192.168.56.203 ansible_python_interpreter=/usr/bin/python

[webservers:vars]
ansible_port=22
http_port=8080

[dbservers]

ansnode3 ansible_ssh_host=192.168.56.204 ansible_python_interpreter=/usr/bin/python

ansnode4 ansible_ssh_host=192.168.56.205 ansible_python_interpreter=/usr/bin/python

[dev:children]
webservers
dbservers

Create a file named called as with_nest_loop_playbook.yml in your project directory

---
 # YAML documents begin with the document separator ---

# the minus in YAML this indicates a list item. The playbook contains a list
 # of plays, with each play being a dictionary
 - hosts: all
   tasks:
     - name: add multiple users
       user:
         name: "{{ item[0] }}"
         state: present
       with_nested:
         - [ 'alice', 'bob' ]
         - [ 'clientdb', 'employeedb', 'providerdb' ]
 # three dots indicate the end of a YAML document
 ...