Ansible Training

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Ansible, a powerful DevOps tools for Automation. Installed Ansible in a management Node, can use SSH to connect devices to perform complex business logic.

Installation

  1. Install ansible in CentOS

    sudo yum -y install ansible

  2. Check Ansible version

    ansible --version

Basic command

  1. Create Inventory file, e.g. host

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    host.ini

    [webserver]
    host1 ansible_host=192.168.150.132
    host2 ansible_host=192.168.150.131

  2. Run with specify inventory
    ansible -i host host1 -m ping

  3. Modify the config file for one off change

  4. Ansible Playbook

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    test.yml

    ---
    - hosts: webserver
      gather_facts: false
      become: true
      
      tasks:
      - name: install th latest version of Apache
        yum:
          name: httpd
          state: absent
        register: result
        
      - debug:
          msg:
          - '{{result}}'

  5. Run Ansible Playbook
    ansible-playbook test_playbook

  6. Run ad-hoc command
    ansible webserver -m yum -a "name=httpd state=absent" --become

Parameterize Playbook

  1. Parameterzie Playbook

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    test.yml

    ---
    - hosts: '{{device_name}}'
      gather_facts: false
      become: true
      
      tasks:
      - name: install th latest version of Apache
        yum:
          name: httpd
          state: absent
        register: result
        
      - debug:
          msg:
          - '{{result}}'

  2. Run with specify parameters
    ansible-playbook playbooks/test.yml --extra-var '{"device_name": ["webserver"]}'

  3. Custom module

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    test_module.py

    from ansible.module_utils.basic import *

    def main():
      module_args = dict(
        a=dict(type='str', required=True),
        b=dict(type='str', required=True),
      )

      module = AnsibleModule(
        argument_spec=module_args,
        supports_check_mode=True
      )

      a = module.params['a']
      b = module.params['b']

      response = {
        "tasks": {
          "key_b": b,
          "key_a": a,
        }
      }

      module.exit_json(changed=True, meta=response)

    if __name__ == '__main__':
      main()

  4. Run custom module with ad-hoc
    ansible webserver -m test_module -a "a=1 b=2"

  5. Run custom module inside playbook

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    test.yml

    ---
    - hosts: '{{device_name}}'
      gather_facts: false
      become: true

      tasks:
      - name: Test Custom Module
        test_module:
          a: "Hello, "
          b: "World"
        register: result

      - debug:
          msg:
          - '{{result}}'

  6. Command to run playbook
    ansible-playbook playbooks/test.yml --extra-var '{"device_name": ["webserver"]}'

Ref

Ansible: https://www.ansible.com/