Strategy

The play parameter strategy can be used to change Ansibles ordering behaviour. There are a couple of available strategies:

• linear - (default) Run tasks in order.
• free - Run tasks in parallel. When running on multiple hosts, a next task runs as fast as the host is done with the current task. Use this when order is not important.
• debug - Run linearly, but ask to run each job.

Here is an example of a playbook using the free strategy:

- name: Install Apache HTTPD
  hosts: webservers
  strategy: free

  tasks:
    - name: Install Apache HTTPD
      ansible.builtin.package:
        name: apache2
        state: present
    
    - name: Start Apache HTTPD
      ansible.builtin.service:
        name: apache2
        state: started

The above playbook would run the two tasks on all targeted nodes in any random order. For example, the order could be:

Strategy linear	Strategy free
1. Install Apache HTTPD on node-1, node-2 and node-2	1. Install Apache HTTPD on node-1
2. Start Apache HTTPD on node-1, node-2 and node-3	2. Install Apache HTTPD on node-2
	3. Start Apache HTTPD on node-2
	4. Install Apache HTTPD on node-3
	5. Start Apache HTTPD on node-1
	6. Start Apache HTTPD on node-3

Assignment

1. Create a playbook that has 2 tasks, one that randomly sleeps up to 30 seconds and another that displays a message. (You can use command to run sleep 30.)
2. Set the strategy to free.

Run the playbook and see that hosts start a task whenever their previous task is done.

Solution

I’ve made a playbook here.