README.md

Ansible Conditionals, loops and delegation

Ansible complex variables (array and dictionaries) are very important in Ansible but it is important to manage/use them as well. On the other hand, Ansible allows to delegate tasks execution to Ansible "slaves".

This lesson dives in conditionals, loops and delegation aspects.

In order to understand this lesson properly, a set of steps have been designed to be implemented in the following section.

ENJOY !!!

Resources

In order to assist this laboratory implementation, a set of resources have been added:

• usertable.mysql (MySQL script to create usernames table)

Steps

• Create an inventory file named "inventory" with a group named "myinstance" and your internal instance IP assigned included
• Create a playbook named "tools-playbook.yml" using "myinstance" as a hosts parameter and <studentxx> as a user. The playbook should use tasks to ensure that the following conditions are met on the managed hosts:
  • Define the following variables:
    • User name variable named "mysql_user" with value "testuser01"
    • User pass variable named "mysql_pass" with value "password01"
    • List or array of database names variable named "mysql_db" with values "testdb01" and "testdb02"
    • Client IP variable named "mysql_client_ip" with value <ip_classroom_instance>
    • List or Array of packages named "mysql_packages" with "mysql-server" and "python3-PyMySQL" included
  • Install the list of packages
  • Start mysqld service if installation packages has changed
  • Restart mysqld service if installation packages has not changed
  • Create two new mysql databases using "mysql_db" variable
  • Create a new user using "mysql_name" and "mysql_pass" variables with read/write rights to "mysql_db" databases from host "mysql_client_ip"
  • Import "usertable.mysql" table file into both "mysql_db" databases delegating the operation to <mysql_client_ip> instance
• Before running your playbook, run the ansible-playbook --syntax-check command to verify that its syntax is correct
• Run the playbook!
• Test the database

Useful Links

For more information, please visit:

• https://docs.ansible.com/ansible/latest/user_guide/playbooks.html
• https://docs.ansible.com/ansible/latest/modules/modules_by_category.html
• https://docs.ansible.com/ansible/latest/user_guide/playbooks_conditionals.html
• https://docs.ansible.com/ansible/latest/user_guide/playbooks_loops.html
• https://docs.ansible.com/ansible/latest/user_guide/playbooks_delegation.html

License

BSD

Author Information

Asier Cidon - Cloud Consultant

[email protected]