Tips And Tricks

Handling nasty expressions in Ansible with grace

There are inevitable moments when you need to do loop calculations in Ansible. You have a group, and you need to extract some variable from all hosts in that group (except those who don’t have this variable), and use it for iteration, or for…

How to extract host lists from ansible inventory?

I just got a serious jq level up, rehearsing it here.

The problem: I need to get list of hosts in the Ansible inventory.

Creating list in loop in Ansible

Today I found a new way to create list for set_fact within loop.

Old approach

- set_fact:
    foo: '{{ (foo|d([])).combine([{"id": hostvars[item]["ID"]}]) }}'
  loop: '{{ groups.mygroup }}'

iteratization of function input in Python

I found a neat trick, which seems obvious but saves me a lot of ugly juggling.

iteratization of the function input in Python

User-friendly way to Return multiple values from a function in Python

assert foo().bar in foo().baz

assert foo().bar in foobar().baz

How to assert that playbook is run with a proper ansible.cfg

Sometime projects has a very stringent requirements on ansible.cfg. F.e. ceph-ansible uses it to specify location for plugins and modules. Some may have quirks for network_cli (f.e. additional retries), etc, etc. I even don’t…

Using default value if string is empty

This little python trick works great in Ansible.

Let’s say you want to set foo to value of the bar, but only if bar is not empty. If bar is empty, you want to use other value (f.e. string “nothing”).

Ugly way to cram your staging into random servers (Ansible)

I call this ‘dirty ansible’. It’s not the shiny best practices, but it so convenient, that it’s hard to resist.

The problem: You run your playbooks at (normal) staging. There is an environment for…

Another ways to have multiple actions in the single handler in Ansible

This is an endless story: your handler need two (or more) actions, and you are allowed to have only one. Because block is not a valid action for a handler.