5.1 Ansible Roles - Handlers and Blocks

We start to use handlers and blocks as well.

Task 1

Create a playbook myhandler.yml which applies a role handlerrole on node2.
The role handlerrole should do the following:
Create a directory newdir in the folder /home/ansible.
If the folder didn’t exist before, then do create a file README.TXT in this folder containing the text “This folder was created at <timestamp>”.
The value of <timestamp> should contain a quite accurate timestamp of when ansible-playbook was run.
Run the playbook several times to see if it is really idempotent.

Solution Task 1

Below is a possible solution:

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$ cat myhandler.yml
---
- hosts: node2
  become: true
  roles:
    - handlerrole

$ ansible-galaxy init roles/handlerrole

$ cat roles/handlerrole/tasks/main.yml
---
- name: create directory
  ansible.builtin.file:
    path: /home/ansible/newdir
    state: directory
    mode: "0755"
  notify: timestamp

$ cat roles/handlerrole/handlers/main.yml
---
- name: create readme with timestamp 
  ansible.builtin.copy:
    dest: /home/ansible/newdir/README.TXT
    content: "This folder was created at {{ ansible_date_time.iso8601 }}"
    mode: "0644"    
  listen: timestamp

$ ansible-playbook myhandler.yml #<-- some changes when run the first time
$ ansible all -a "cat /home/ansible/newdir/README.TXT" #<-- show created files with it's content
$ ansible-playbook myhandler.yml #<-- no changes here, idempotent!

Task 2

Write a playbook download.yml which runs a role downloader on node2.
The role downloader should try to download a file from a non-existing URL.
The role should be able to handle errors. Let it write the message “Download failed!” to standard output if the download task failed. The playbook must keep on running and shall not exit after this message.
Regardless of download success, output a message at the end of the play informing that the download attempt has finished.
Use a block: to do these tasks.
Add another ansible.builtin.debug task after the block to confirm the run continues even after a download fail.
Run the playbook download.yml.

Solution Task 2

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$ cat download.yml 
---
- hosts: node2
  become: true
  roles:
    - downloader

$ ansible-galaxy init roles/downloader

$ $ cat roles/downloader/tasks/main.yml 
---
# tasks file for roles/downloader
- block:
    - name: Download things from the internet
      ansible.builtin.get_url:
        url: https://www.not_existing_url.com/not_existing_file
        dest: /tmp/
        mode: "0400"
  rescue:
    - name: "Print an error message"
      ansible.builtin.debug:
        msg: "Download failed!"
  always:
    - name: "Print confirmation"
      ansible.builtin.debug:
        msg: "Download attempt finished."

- name: "A task after the block"
  ansible.builtin.debug:
    msg: "This gets executed after the block"

$ ansible-playbook download.yml

Note

Note the failed download task, but the playbook finished nonetheless.

All done?

Last modified February 14, 2025: Nitpicking 3 nitpick bugaloo (#224) (2284a0f)