Access a group's variables without going through a known host

[laashe]

Proposal: Enable access to group variables without going through a known host

Author: Lars <@laashe>

Date: 2018/05/30

• Status: New
• Proposal type: feature

Motivation

When working with a role to set up and configure DNS, I came across the need to access group variables without necessarily knowing any specific hosts in the group. Specifically, I wanted to create a new DNS zone for a certain group, and I needed information on domain, two first octets of the IP, etc. I could define the necessary information in group_vars/target_group.yml, but to access them I have to go through a host in that group: {{ hostvars['some_host_in_target_group']['desired_group_variable'] }}. Since I don't necessarily know, or at least I don't need to know, any hosts in target_group, I would very much have liked to have some sort of the following syntax available instead: {{ groupvars['target_group']['desired_group_variable'] }}. This is a very specific use case, but I think there must be multiple other use cases in which this would be very useful.

[agaffney]

You can do something like hostvars[groups.target_group.0].desired_group_variable to access a variable from group_vars without knowing the name of one of the hosts in the group.