How can I add 30 seconds time delay between hosts in this ansible script?

Question

    - hosts: dr
      become: true
      become_user: root

      tasks:
        - name: yum
          shell: "hostname >> /tmp/ycu.txt; yum history | head -5 >> /tmp/ycu.txt"

        - name: Specifying a path directly
          fetch:
            src: /tmp/ycu.txt
            dest: /tmp/{{ inventory_hostname }}/
            flat: yes

How can I add a 30 seconds time delay between hosts in this ansible script?

Answer 1

By default, Ansible processes multiple hosts in parallel. If you really don't want to do that, the first thing you need to do is adjust the serial parameter for this play:

- hosts: dr
  become: true
  become_user: root
  serial: 1
  tasks:
  - name: yum
    shell: "hostname >> /tmp/ycu.txt; yum history | head -5 >> /tmp/ycu.txt"

  - name: Fetch remote file
    fetch:
      src: /tmp/ycu.txt
      dest: /tmp/{{ inventory_hostname }}/
      flat: yes

Now that you're running the task on one host at a time, you can introduce a 30 second delay using the pause module:

- hosts: dr
  become: true
  become_user: root
  serial: 1
  tasks:
  - name: yum
    shell: "hostname >> /tmp/ycu.txt; yum history | head -5 >> /tmp/ycu.txt"

  - name: Fetch remote file
    fetch:
      src: /tmp/ycu.txt
      dest: /tmp/{{ inventory_hostname }}/
      flat: yes

  - name: pause for 30 seconds
    pause:
      seconds: 30

The output of the above would look something like:

PLAY [all] **********************************************************************************************

TASK [Gathering Facts] **********************************************************************************
ok: [node1]

TASK [yum] **********************************************************************************************
changed: [node1]

TASK [Fetch remote file] ********************************************************************************
changed: [node1]

TASK [pause for 30 seconds] *****************************************************************************
Pausing for 30 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
ok: [node1]

PLAY [all] **********************************************************************************************

TASK [Gathering Facts] **********************************************************************************
ok: [node2]

TASK [yum] **********************************************************************************************
changed: [node2]

TASK [Fetch remote file] ********************************************************************************
changed: [node2]

TASK [pause for 30 seconds] *****************************************************************************
Pausing for 30 seconds
(ctrl+C then 'C' = continue early, ctrl+C then 'A' = abort)
ok: [node2]

PLAY RECAP **********************************************************************************************
node1                      : ok=4    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0
node2                      : ok=4    changed=2    unreachable=0    failed=0    skipped=0    rescued=0    ignored=0

Answer 2

You can solve your issue in one task by adding a sleep to the command and use throttle:

- name: yum
  shell: "hostname >> /tmp/ycu.txt; yum history | head -5 >> /tmp/ycu.txt ; sleep 30"
  throttle: 1

This will also decrease the total time of the playbook run, since not all tasks will be executed host by host, but only that task...