How do I make an idempontent shell in Ansible
ansible
Solution
You should use the ansible `apt` module to install `python-apt`, which will be idempotent out of the box: http://docs.ansible.com/apt_module.html
E.g.
- name: install python-apt
apt: name=python-apt state=present
(Note using the apt module should automatically install `python-apt` on the remote host so I'm not sure why you would need to manually install it, see https://github.com/ansible/ansible/issues/4079)
Edit: If for some reason you can't use the inbuilt `apt` module to install python apt, the `shell` module provides the `creates` parameter to help make it idempotent.
- name: install python-apt
shell: apt-get install -y python-apt >> /home/x/output.log creates=/home/x/output.log
What this means is that the shell module will not run if `/home/x/output.log` already exists.
Problem
I am using Ansible and I have a little problem trying to make idempotent a shell execution. The first I do is install python-apt package because I need it to use the apt module for install others packages. But every time that I run my playbook the shell task always runs and I want to make it idempotent. Here is my shell task: ``` - name: install pyton-apt shell: apt-get install -y python-apt ``` And here is the output, always running the above task: ``` $ ansible-playbook -i hosts site.yml PLAY [docker] ***************************************************************** GATHERING FACTS *************************************************************** ok: [10.0.3.240] TASK: [docker | install pyton-apt] ******************************************** changed: [10.0.3.240] TASK: [docker | install unzip] ************************************************ ok: [10.0.3.240] PLAY RECAP ******************************************************************** 10.0.3.240 : ok=3 changed=1 unreachable=0 failed=0 ```