Added note about steps only required for DR Alpha

doc/gitlab-geo/configuration.md

@@ -46,7 +46,7 @@ first two steps of the [Setup instructions](README.md#setup-instructions):
 1. You have set up the database replication.
 1. Your secondary node is allowed to communicate via HTTP/HTTPS and SSH with
    your primary node (make sure your firewall is not blocking that).
-1. You nodes must have a NTP service running to synchronize the clocks. 
+1. You nodes must have a NTP service running to synchronize the clocks.
    You can use different timezones, but the hour relative to UTC can't be more
    than 60 seconds off from each node.
 
@@ -150,23 +150,27 @@ sensitive data in the database. Any secondary node must have the
     sudo -i
     ```
 
-1. Edit the /etc/gitlab/gitlab.rb:
+1. (This step is required only if you want to enable the new Disaster Recovery
+   feature in Alpha shipped in GitLab 9.0) Edit the /etc/gitlab/gitlab.rb:
 
     ```
     geo_postgresql['enable'] = true
     ```
 
-1. Create `database_geo.yml` with the information of your secondary PostgreSQL
-   database.  Note that GitLab will set up another database instance separate
-   from the primary, since this is where the secondary will track its internal
-   state:
+1. (This step is required only if you want to enable the new Disaster Recovery
+   feature in Alpha shipped in GitLab 9.0) Create `database_geo.yml` with the
+   information of your secondary PostgreSQL database.  Note that GitLab will
+   set up another database instance separate from the primary, since this is
+   where the secondary will track its internal state:
 
     ```
     sudo cp /opt/gitlab/embedded/service/gitlab-rails/config/database_geo.yml.postgresql /opt/gitlab/embedded/service/gitlab-rails/config/database_geo.yml
     ```
 
-1. Edit the content of `database_geo.yml` in `production:` like the example below:
-   
+1. (This step is required only if you want to enable the new Disaster Recovery
+   feature in Alpha shipped in GitLab 9.0) Edit the content of
+   `database_geo.yml` in `production:` like the example below:
+
    ```yaml
    #
    # PRODUCTION
@@ -180,16 +184,18 @@ sensitive data in the database. Any secondary node must have the
      # password:
      host: /var/opt/gitlab/geo-postgresql
      port: 5431
-   
+
    ```
 
-1. Reconfigure GitLab:
+1. (This step is required only if you want to enable the new Disaster Recovery
+  feature in Alpha shipped in GitLab 9.0) Reconfigure GitLab:
 
     ```
     sudo gitlab-ctl reconfigure
     ```
 
-1. Set up the Geo tracking database:
+1. (This step is required only if you want to enable the new Disaster Recovery
+  feature in Alpha shipped in GitLab 9.0) Set up the Geo tracking database:
 
     ```
     sudo gitlab-rake geo:db:setup