Add the Disaster Recovery info for source installations

[ci skip]

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. Your nodes must have an 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.
 
@@ -151,7 +151,7 @@ sensitive data in the database. Any secondary node must have the
     ```
 
 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:
+   feature in Alpha shipped in GitLab 9.0) Edit `/etc/gitlab/gitlab.rb`:
 
     ```
     geo_postgresql['enable'] = true
@@ -169,7 +169,7 @@ sensitive data in the database. Any secondary node must have the
 
 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:
+   `database_geo.yml` in `production:` to be like the following:
 
    ```yaml
    #
@@ -184,7 +184,6 @@ sensitive data in the database. Any secondary node must have the
      # password:
      host: /var/opt/gitlab/geo-postgresql
      port: 5431
-
    ```
 
 1. (This step is required only if you want to enable the new Disaster Recovery

doc/gitlab-geo/configuration_source.md

@@ -140,7 +140,9 @@ sensitive data in the database. Any secondary node must have the
     sudo -i
     ```
 
-1. Create `database_geo.yml` with the information of your secondary PostgreSQL database.
+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 this must be a totally different instance from the primary, since this
    is where the secondary will track its internal state:
 
@@ -148,7 +150,9 @@ sensitive data in the database. Any secondary node must have the
     sudo cp /home/git/gitlab/config/database_geo.yml.postgresql /home/git/gitlab/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:` to be like the following:
 
      ```yaml
      #
@@ -163,12 +167,14 @@ sensitive data in the database. Any secondary node must have the
        # password:
        host: /var/opt/gitlab/geo-postgresql
        port: 5431
-   
      ```
 
-1. Create the database `gitlabhq_geo_production` in that PostgreSQL instance.
+1. (This step is required only if you want to enable the new Disaster Recovery
+   feature in Alpha shipped in GitLab 9.0) Create the database
+   `gitlabhq_geo_production` in that PostgreSQL instance.
 
-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:
 
     ```
     bundle exec rake geo:db:migrate