.vimrc

autocmd FileType yaml setlocal ai ts=2 sw=2 et

Ad-hoc commands

-m command is default and can be omitted

Output on one line with ansible ... -o

-m shell when using | or >

Configuration file

Get config file location

ansible --version
...
  config file = ...

ansible dev -i inventory --list-hosts -v
Using ... as config file
...

Configuration file precedence

Ansible looks for its configuration file in a number of places in order of precedence. The first configuration file found is used. All others are ignored.

$ANSIBLE_CONFIG
./ansible.cfg
~./ansible.cfg
/etc/ansible/ansible.cfg

Multi-line strings

Preserve newline characters within the string

include_newlines: |
          ACME
          123 Main Street
          Atlanta, GA 30303

Convert newline characters to spaces and remove leading white spaces

fold_newlines: >
          This is
          a very long,
          long, long, long
          sentence.

Playbook syntax check

ansible-playbook --syntax-check playbook.yml

Variables

If the same variable name is defined at more than one level, the higher wins. Variables defined by the inventory are overridden by variables defined by the playbook, which are overridden by variables defined on the command line.

It is recommended practice to define inventory variables using host_vars and group_vars directories, and not to define them directly in the inventory file or files. Host variables take precedence over group variables, but variables defined by a playbook take precedence over both.

The include_vars module is one more way to set variables in a playbook from an external file. It overrides any values set through the methods above.

When a variable is used as the first element to start a value, quotes are mandatory:

  with_items:
    - "{{ foo }}"

Definition in playbook

- hosts: all
  vars:
    user: joe
    comment: "Joe"

Definition in vars_files

- hosts: all
  vars_files:
    - vars/users.yml

vars_files wins over vars.

Registered variables

    command: ps
    register: ps_result
  
  - debug:
    msg: "{{ ps_result.stdout }}"

  - debug:
    var: ps_result
    verbosity: 2

Magic variables

hostvars lets you ask about the variables of another host, including facts that have been gathered about that host. If, at this point, you haven’t talked to that host yet in any play in the playbook or set of playbooks, you can still get the variables, but you will not be able to see the facts.

group_names is a list (array) of all the groups the current host is in. This can be used in templates using Jinja2 syntax to make template source files that vary based on the group membership (or role) of the host.

groups is a list of all the groups (and hosts) in the inventory. This can be used to enumerate all hosts within a group.

inventory_hostname is the name of the hostname as configured in Ansible’s inventory host file. This can be useful for when you don’t want to rely on the discovered hostname ansible_hostname or for other mysterious reasons. If you have a long FQDN, inventory_hostname_short also contains the part up to the first period, without the rest of the domain.

inventory_file is the pathname and the filename pointing to the Ansible’s inventory host file.

Loops

  service:
    name: "{{ item }}"
    state: started
  with_items:
    - postfix
    - dovecot

  mysql_user:
    name: "{{ item[0] }}"
    priv: "{{ item[1] }}.*:ALL"
  ...
  with_nested:
    - [ 'joe', 'jane' ]
    - [ 'clientdb', 'employeedb', 'providerdb' ]

Loop Keyword	Description
`with_file`	Takes a list of control node file names. `item` is set to the content of each file in sequence.
`with_fileglob`	Takes a file name globbing pattern. `item` is set to the content of each file in a directory on the control node that matches that pattern, in sequence, non-recursively.
`with_sequence`	Generates a sequence of items in increasing numerical order. Can take `start` and `end` arguments which have a decimal, octal, or hexadecimal integer value.
`with_random_choice`	Takes a list. `item` is set to one of the list items at random.

LanesG/ansible