Reduce step complexity and make DNS optional

doc/gitlab-geo/disaster-recovery.md

@@ -19,15 +19,20 @@ but you can do it manually if you have `root` access to the machine.
 
 1. Take down your **primary** node.
 
-    If you have SSH access to the primary node, SSH into your **primary**
-    node, and stop GitLab.
+    SSH into your primary node and stop GitLab.
 
     ```
     sudo gitlab-ctl stop
     ```
 
-    Make sure the primary node will not come up while promoting the secondary
-    node to primary else you may lose data.
+    If you do not have SSH access to your primary node take the machine
+    offline. Depending on the nature of your primary node this may mean
+    physically disconnecting the machine, stopping a virtual server,
+    reconfiguring load balancers, or changing DNS records (see next step).
+
+    Preventing the original primary from coming online during this process is
+    necessary to ensure data isn't added to the original primary that will not
+    be replicated to the newly promoted primary.
 
 1. SSH in to your **secondary** node and login as root:
 
@@ -35,68 +40,52 @@ but you can do it manually if you have `root` access to the machine.
     sudo -i
     ```
 
+1. Optional. Update the DNS records and the `external_url`.
+    
+    Updating the DNS records for the primary domain to point to the secondary
+    node will prevent the need to update all references to the primary domain
+    to the secondary domain, like changing Git remotes and API URLs.
+
+    After updating the DNS records, edit `/etc/gitlab/gitlab.rb` to reflect the
+    new URL:
+
+    ```
+    # Change the existing external_url configuration
+    external_url 'https://gitlab.example.com'
+    ```
+
 1. Edit `/etc/gitlab/gitlab.rb` to reflect its new status as primary node.
 
     Remove the following line:
 
     ```
-    ## DELETE THIS LINE, or update the value to false
+    ## REMOVE THIS LINE
     geo_secondary_role['enable'] = true
     ```
 
-    Add the following lines, replacing the IP addresses with addresses
-    appropriate to your network configuration:
+    Add the following line:
 
     ```
+    ## ADD THIS LINE
     geo_primary_role['enable'] = true
-
-    ##
-    ## Primary address
-    ## - replace '1.2.3.4' with the primary private address
-    ##
-    postgresql['listen_address'] = '1.2.3.4'
-    postgresql['trust_auth_cidr_addresses'] = ['127.0.0.1/32','1.2.3.4/32']
-
-    ##
-    ## Disable automatic database migrations temporarily
-    ## (until PostgreSQL is restarted and listening on the private address).
-    ##
-    gitlab_rails['auto_migrate'] = false
     ```
 
-    A new secondary is not added at this time. You should add a new secondary
-    after you have completed the entire process of promoting the secondary to
-    the primary node.
-
-    Refer to [Geo Replication database documention](
-    database.html#step-1-configure-the-primary-server) for more details.
+    A new secondary should not be added at this time. If you want to add a new
+    secondary, do this after you have completed the entire process of promoting
+    the secondary node to the primary node.
 
 1. Promote the secondary geo node to primary node. Execute:
 
     ```
-    sudo gitlab-ctl promote-to-primary-node
+    gitlab-ctl promote-to-primary-node
     ```
 
 1. Verify you can connect to the newly promoted primary using the URL used
    previously for the secondary.
-1. Update the DNS records for the primary to reflect the public address of the
-   newly promoted primary.
-1. After the DNS changes have propagated, edit `/etc/gitlab/gitlab.rb` to
-   reflect it's new URL:
-
-    ```
-    # Change the existing external_url configuration
-    external_url 'https://gitlab.example.com'
-    ```
-
-    Reconfigure GitLab to apply the change:
-
-    ```
-    gitlab-ctl reconfigure
-    ```
+1. Success! The secondary node has now been promoted to primary node.
 
-1. Success! The secondary node has now been promoted to primary node and is
-   accessible from the URL of the previous primary.
+    If you updated the DNS records for the primary domain, these changes may
+    not have yet propogated depending on the previous DNS records TTL.
 
 To bring your old primary node back into use as a working secondary, you need to
 run `gitlab-ctl reconfigure` against the node and then follow the