• Overview
• Install
• Configuration
  • Re-use SSH connections
  • Output formats
  • ansible_managed
  • Default to showing diff
• Convergence
• References

Overview

I use Ansible¹ a lot, both at work and for the sudo.is infrastructure², see my infra repo.

Install

Use pipx:

$ pipx install --include-deps ansible

To install additonal Python dependencies, use inject:

$ pipx inject ansible $dependency

Upgrading existing Ansible:

$ pipx upgrade --include-injected ansible

{{ [ansible_default_ipv4.address] | ansible.utils.ipaddr("private") }}

TASK [role: task] ***************************
An exception occurred during task execution.

fatal: [sudo.is]: FAILED! => {
    "changed": false
}

MSG:
AttributeError: 'IPNetwork' object has no attribute 'is_private'

$ pipx inject ansible netaddr==0.10.0

TASK [docker ] ******************************
fatal: [sudo.is]: FAILED! => {
    "changed": false
}

MSG:

Error connecting: Error while fetching server API version: Not supported URL scheme http+docker

$ ansible-galaxy collection install community.docker --force

Configuration

Re-use SSH connections

For faster ssh connections, enable pipelining and use the ControlPersis features of ssh to re-use SSH connections instead of always reconnecting:

[defaults]
forks = 20

[ssh_connection]
ssh_args = -o ControlMaster=auto -o ControlPersist=60s -o PreferredAuthentications=publickey
control_path = /tmp/ansible-ssh-%%h-%%p-%%r
pipelining = true

This will re-use connections for 60s and then close them.

Output formats

Ansible calls output formats "callbacks"⁷:

• debug: indents Ansible's output and data structures, this is a good and sane default to use.

The output format/callback can be set in the ansible.cfg config files:

[defaults]
stdout_callback = debug

The output format can also be set via an environment variable:

ANSIBLE_STDOUT_CALLBACK="debug"

Since environment variables take precedence over the config file, this will use the output format debug regardless of config file values.

ansible_managed

By default, the ansible_managed variable will render to "Ansible managed", but it can provide more useful information, such as the path of the template in a Git repo.

[defaults]
ansible_managed = ansible_managed:{{{{ lookup('pipe', 'git rev-parse --show-toplevel')|basename }}}}/roles/{{{{ role_name }}}}/{{{{ template_path }}}}{{{{ lookup('pipe', 'git log -1 ' + template_fullpath|quote) | default(false, true) | ternary("", ",UNCOMITTED") }}}}

This will include the path to the source template, as well as the short commit hash that the file is templated from.

Default to showing diff

To make Ansible show diffs by default:

[diff]
always = true

Makes --diff the default for ansible-playbook and friends.

Convergence

Prevent ansible from printing every ok task with:

ANSIBLE_DISPLAY_SKIPPED_HOSTS="false"
ANSIBLE_DISPLAY_OK_HOSTS="false"

This will only print failed or changed tasks to stdout, makes it easy to parse the output into a convergence report.

References