Mastering Ansible

Chapter 1
4. Rest of the variables defined in inventory
5. Facts discovered about a system
6. Role defaults
This list is a useful starting point, however things are a bit more nuanced, as we
will explore.
Extra-vars
Extra-vars, as supplied on the command line, certainly overrides anything else.
Regardless of where else a variable might be defined, even if it's explicitly set in a
play with set_fact, the value provided on the command line will be the value used.
Connection variables
Next up are connection variables, the behavioral variables outlined earlier. These
are variables that influence how Ansible will connect to and execute tasks on a
system. These are variables like ansible_ssh_user, ansible_ssh_host, and others
as described in the earlier section regarding behavioral inventory parameters. The
Ansible documentation states that these come from the inventory, however, they can
be overridden by tasks such as set_fact. A set_fact module on a variable such
as ansible_ssh_user will override the value that came from the inventory source.
There is a precedence order within the inventory as well. Host-specific definitions
will override group definitions, and child group definitions will override parent of
group definitions. This allows for having a value that applies to most things in a
group and overrides it on specific hosts that would be different. When a host belongs
to multiple groups and each group defines the same variable with different values,
the behavior is less defined and strongly discouraged.
Most everything else
The "most everything else" block is a big grouping of sources. These include:
• Command line switches
• Play variables
• Task variables
• Role variables (not defaults)
[ 29 ]
www.allitebooks.com