Read Ansible variables of another group

Question

Here is an example of inventory file:

[web_servers]
web_server-1 ansible_ssh_host=xxx ansible_ssh_user=yyy

[ops_servers]
ops_server-1 ansible_ssh_host=xxx ansible_ssh_user=zzz

Furthermore, web_servers group has specific vars in group_vars/web_servers:

tomcat_jmx_port: 123456

How can I access tomcat_jmx_port var when dealing with ops_servers ?

Some will probably say I need a commun ancessor group (like all) to put common vars, but this is just an example, in true life there are many vars I want to access from ops_servers, and I want to keep things clear so tomcat_jmx_port have to stay in web_servers group_vars file.

In fact, I need a kind of local lookup.

Any idee ?

Thanks for your help.

Answer 1

To access variables from an arbitrary group you'd use the global variable groups which gives you access to all the vars of the hosts in the group. So something like this would return the name of the first host in the web_servers group:

{{ groups['web_servers'][0] }}

To access the individual variables of a host you would do something like this:

{{ hostvars['somehost']['ansible_default_ipv4']['address'] }}

This would return the default IP address of the host named somehost.

You can easily combine hostvars & groups if you need something more complex:

{{ hostvars[groups['web_servers'][0]]['ansible_default_ipv4']['address'] }}

This one will give you the default IP address of the first host in your web_servers group.

Answer 2

You can also "include" the variables in the run context using

- include_vars: group_vars/web_servers

Notice that if you have variables with the same name in the context they will be overwritten.

This will make your variable available as {{ tomcat_jmx_port }}