Ansible

Misc

Resources

Sample code:

Some common modules:

Organization

Folder structure

Operational tasks

For operational tasks (restart a service, install a patch, etc), don’t put them in roles. Instead put the tasks directly into the playbooks.

Global directives

These are directives that can be applied to any module

changed_when

Override the conditions determining whether a task was changed or not

This can also be used to never (or always) report a task as changed:

# Don't report this as changed
changed_when: no

delegate_to

Used to run a task on a specific server. Pair with run_once to make sure the task only gets run once per play.

For example, to limit a task to the first server in a group:

- name: Some task
  ...
  delegate_to: ""
  run_once: yes

failed_when

Override the conditions determining whether a task has failed or not

ignore_errors

Keep going if the task fails

notify

Run a handler if the task was changed

register

"changed": true,
"cmd": "if ! sudo /sbin/service tomcat6 status; then sudo /sbin/service tomcat6 start; fi",
"rc": 0,
"stderr": "",
"stdout": "tomcat6 is stopped\u001b[60G[\u001b[0;32m  OK  \u001b[0;39m]\r\nStarting tomcat6: \u001b[60G[\u001b[0;32m  OK  \u001b[0;39m]",
"stdout_lines": [
    "tomcat6 is stopped\u001b[60G[\u001b[0;32m  OK  \u001b[0;39m]",
    "Starting tomcat6: \u001b[60G[\u001b[0;32m  OK  \u001b[0;39m]"
],

run_once

Only run the task once per play.

Note: this will always run on the first host in the play, which may change if you use --limit. To make sure it always runs on one specific host, use run_once with delegate_to.

when

Run a task based on a condition

with_items

Pass a list of items to be iterated over in a task

Templates

Adding sections to a file conditionally

Note: Make sure all blank lines and template lines ({% %}) have no trailing whitespace!

{% if inventory_hostname in ['idp1.example.org', 'idp2.example.org'] %}
<!-- Metadata for sp1.example.org -->
<metadata:MetadataProvider id="sp1.example.org" xsi:type="metadata:FileBackedHTTPMetadataProvider"
    metadataURL="https://sp1.example.org/Shibboleth.sso/Metadata"
    backingFile="/opt/shibboleth-idp/metadata/sp1.example.org-metadata.xml" />

{% endif %}
<!-- Metadata for sp2.example.org -->

Variables

groups[‘group_name’]

All of the hosts in a particular group matched by the inventory file for the current play

inventory_file

The relative path to the inventory file used by the current play

Ex:

ansible-playbook -i inventory/development...
"inventory_file": "inventory/development"

inventory_hostname

The hostname of the current server

play_hosts

All of the hosts included in the current play

Examples

Specify hosts on the command line

https://stackoverflow.com/a/18255256/399105

One server (the comma at the end is important so that the inventory appropriately gets converted to a list):

ansible all -i server1.example.org,

Multiple servers:

ansible all -i server1.example.org,server2.example.org

Show the output of a command

http://stackoverflow.com/a/20981211/399105

Use the last two lines here:

- name: Copy some file
  copy:
    src: /path/to/some/file
    dest: /path/to/some/file
  register: result

- debug: var=result.stdout_lines

Note: when using debug in a handler, you must provide it a name and call the handler directly since handlers aren’t run automatically

Remove a file if another file exists

- stat:
    path: /etc/pki/tls/certs/ThawteSSLCAG2.crt
  register: thawtesslcag2

- file:
    path: ~/ThawteSSLCAG2.crt
    state: absent
  when: thawtesslcag2.stat.exists