DevOps Classroomnotes 10/Apr/2022

Ansible-Controlling playbook execution

• Forks:
  • Maximum number of simultaneous connections Ansible made on each Task
  • How to set it:
    • /etc/ansible/ansible.cfg
      [defaults]
forks = 100
    • ansible-playbook -f 100 my_playbook.yml
      
• Strategy:
  • Types
    • linear
    • free
    • debug
  • How to set strategy
    • In playbook
      “`yaml

    <li>hosts: all
    become: yes
    strategy: free
    “`

    • /etc/ansible/ansible.cfg
      [defaults]
strategy = free
      

Keywords that effect ansible playbook execution

• serial:
  • if you want to manage only few machines at a time.
  • You can define how many hosts Ansible should manage at a single time by using the serial keywork
    “`yaml

  </ul>
  <hr />
  <ul>
  <li>name: test
  hosts: all
  serial: 2
  gather_facts: no
  tasks:<ul>
  <li>name: first task
  debug:
  msg: "first task"</li>
  <li>name: second task
  debug:
  msg: "second task"
  “`

• Let assume we have 4 nodes
  “`
  PLAY [all] ##################################</li>
  </ul>
  TASK [ first task] ##########################
  changed [web1]
  changed [web2]
  TASK [ second task] ##########################
  changed [web1]
  changed [web2]
  PLAY [all] ##################################
  TASK [ first task] ##########################
  changed [web3]
  changed [web4]
  TASK [ second task] ##########################
  changed [web3]
  changed [web4]
  “`
  * throttle: sets number of workers for a particular task. This can be set at block or task.
  * run_once: Runs only one node in the inventory
  * ignore_errors: ignores all the errors occured during playbook execution
  * ignore_unreachable: ignores unreachable nodes
  * order: Order in which nodes from inventory are picked
  

Ansible Tower Installation

• Refer Here
• For ansible tower installation and usage please refer classroom video

Ansible Vault

• Ansible Vault helps secure vital secret information.
• Ansible vault can encrypt variables or even entire files and YAML Playbooks
• Create an encrypted file in Ansible
  • Create a file with username: tomcat and password: tomcat in yaml
    
• view the encrypted file
  
• edit the content
  
• if you want to change the password for the file
  
• Encrypting existing files using vault
  
• Decryption of the encrypted file