execute one task of a playbook locally and the rest on the remote hosts?

[Mike Eggleston]

I'm working on a playbook to deploy an internal application to internal hosts. This application is delivered by development to QA in a *.tar.gz file. The file is staged and deployed to QA (by me) in that *.tar.gz file. What I would like/am thinking of is something like:

$ ansible-playbook remote-group -k -e '{"qahost":"qaserver","version":2.75.26.1","path":"/home/app/app_2.75.26.1.tar.gz"}'

and the playbook would be something like:

---
- hosts: v2app
  gather_facts: yes

  vars:

    qahost: "{{ qahost }}"

    version: "{{ version }}"
    remotepath: "{{ path }}"

    localpath: "/tmp/{{version}}.tar.gz"

  tasks:
    - name: bring file locally

      command: scp "{{qahost}}":"{{remotepath}}" "{{localpath}}"

      local: true

    # localpath referes to /tmp, so using it twice means once on the local server and once on the remote app server

    - name: copy the deployment file from QA locally
      copy:src={{localpath}} dest={{localpath}}

    - name: extract the deployment file on the app server

      command: tar -xzf {{localpath}}

    # still testing, so using /tmp for all updates

    - name: make a copy of the application

      shell: rm -rf /tmp/app ; cp -r -p /opt/app /tmp

    - name: sync the new files to the application

      shell: cd /tmp/app; rsync -a {{localpath}} .

    - name: clean up

      command: rm -f {{localpath}}

(I'm just typing from memory and haven't syntax checked the above.)

How can I execute a single task of a playbook on the local server and the rest of the tasks on the remote servers? (Is this even possible?)

TIA

Mike

[Auralan]

Hi,

One way to do this is to append your tasks with a when statement in conjunction the special variables inventory_hostname and group_names.

Something like this should work for you:

- name: "this only runs on localhost"

shell: /foo

when: (inventory_hostname == 'localhost')

- name: "this runs on every host in the servers group"

shell: /bar

when: ('servers' in group_names)

[Mike Eggleston]

That's a great idea. Thank you.

Mike

[Karl Auer]

Haven't checked this, but I think you can have multiple sections in a playbook with different hosts. Maybe not.

Try

- hosts: localhost

   ...

- hosts: something_else

   ...

I assume (always dangerous) that if it works at all the hosts sections would be processed in order, so you could rely on the localhost stuff happening first.

Regards, K.

On Wed, Aug 21, 2019 at 12:41 AM Mike Eggleston <mikee...@gmail.com> wrote:

That's a great idea. Thank you.

Mike

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[Zolvaring]

I think what you're looking for is the 'delegate_to' task parameter. If you wanted the local action to only run once you can combine this with the 'run_once' task parameter -- for your example

- name: bring file locally

      command: scp "{{qahost}}":"{{remotepath}}" "{{localpath}}"

      delegate_to: localhost

      run_once: true