[control_node]
workstation.lab.example.com

[db_servers]
serverd.lab.example.com

[db_clients]
serverc.lab.example.com

[web_servers]
serverc.lab.example.com

[lb_servers]
servera.lab.example.com

[cache_servers]
serverb.lab.example.com

[email_servers]
servera.lab.example.com
serverb.lab.example.com
serverc.lab.example.com
serverd.lab.example.com