Variables

Most playbooks and roles will make use of variables, which can be overridden in several ways. The simplest way is to create files in the host_vars and groups_vars folders; these allow you to override variables either based on the host or group membership, respectively.

Create a /etc/ansible/group_vars directory. Create a file in group_vars called mons and place the following inside it:

a_variable: "foo"

Create a file in group_vars called osds and place the following inside it:

a_variable: "bar"

Variables follow a precedence order; you can also create an all file which will apply to all groups. However, a variable of the same name that is in a more specific matching group will override it. Ceph Ansible modules make use of this to allow you to have a set of default variables and then specify different values for the specific roles.