Adds guidance for geo_node_name

doc/administration/geo/replication/configuration.md

@@ -190,6 +190,9 @@ keys must be manually replicated to the **secondary** site.
    gitlab_rails['geo_node_name'] = '<site_name_here>'
    ```
 
+   We recommend mentioning specific names for the `geo_node_name` such as `gitlab-usa` instead of generic names, such as `geo`.
+   This makes the failover process easier because the physical location does not change, but the Geo site role can.
+   
 1. Reconfigure **each Rails and Sidekiq node on your secondary** site for the change to take effect:
 
    ```shell