In a playbook, you may want to execute different tasks, or have different goals, depending on the value of a fact (data about the remote system), a variable, or the result of a previous task. You may want the value of some variables to depend on the value of other variables. Or you may want to create additional groups of hosts based on whether the hosts match other criteria. You can do all of these things with conditionals.
Ansible uses Jinja2 tests and filters in conditionals. Ansible supports all the standard tests and filters, and adds some unique ones as well.
Example of conditionals:
tasks:
- name: Register a variable, ignore errors and continue
ansible.builtin.command: /bin/false
register: result
ignore_errors: true
- name: Run only if the task that registered the "result" variable fails
ansible.builtin.command: /bin/something
when: result is failed
- name: Run only if the task that registered the "result" variable succeeds
ansible.builtin.command: /bin/something_else
when: result is succeeded
- name: Run only if the task that registered the "result" variable is skipped
ansible.builtin.command: /bin/still/something_else
when: result is skipped
Sometimes you want to repeat a task multiple times. In computer programming, this is called a loop.
Example of sіmple loop:
- ansible.builtin.debug:
mgs: "{{ item }}"
with_items:
- one
- two
- three
example of more complex loop:
- name: Add several users
ansible.builtin.user:
name: "{{ item.name }}"
state: present
groups: "{{ item.groups }}"
loop:
- { name: 'testuser1', groups: 'wheel' }
- { name: 'testuser2', groups: 'root' }