Add note to collect CONSUL_SERVER_NODES in HA docs

There are several instances in our HA docs where an example of
`Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z` is given,
but this value isn't explicitly stated. It should be
the IP addresses or DNS records of the Consul server nodes.

doc/administration/high_availability/gitaly.md

@@ -24,23 +24,25 @@ Continue configuration of other components by going back to:
 
 > [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/issues/3786) in GitLab 12.0.
 
-  1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
+1. Make sure to collect [`CONSUL_SERVER_NODES`](database.md#consul-information), which are the IP addresses or DNS records of the Consul server nodes, for the next step. Note they are presented as `Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z`
 
-     ```ruby
-     # Enable service discovery for Prometheus
-     consul['enable'] = true
-     consul['monitoring_service_discovery'] =  true
+1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
 
-     # Replace placeholders
-     # Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
-     # with the addresses of the Consul server nodes
-     consul['configuration'] = {
-        retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
-     }
+   ```ruby
+   # Enable service discovery for Prometheus
+   consul['enable'] = true
+   consul['monitoring_service_discovery'] =  true
 
-     # Set the network addresses that the exporters will listen on
-     node_exporter['listen_address'] = '0.0.0.0:9100' 
-     gitaly['prometheus_listen_addr'] = "0.0.0.0:9236"
-     ```
+   # Replace placeholders
+   # Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
+   # with the addresses of the Consul server nodes
+   consul['configuration'] = {
+      retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
+   }
 
-  1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.
+   # Set the network addresses that the exporters will listen on
+   node_exporter['listen_address'] = '0.0.0.0:9100'
+   gitaly['prometheus_listen_addr'] = "0.0.0.0:9236"
+   ```
+
+1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.

doc/administration/high_availability/gitlab.md

@@ -138,6 +138,8 @@ need some extra configuration.
 
 If you enable Monitoring, it must be enabled on **all** GitLab servers.
 
+1. Make sure to collect [`CONSUL_SERVER_NODES`](database.md#consul-information), which are the IP addresses or DNS records of the Consul server nodes, for the next step. Note they are presented as `Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z`
+
 1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
 
    ```ruby

doc/administration/high_availability/monitoring_node.md

@@ -16,6 +16,8 @@ Omnibus:
    package you want using **steps 1 and 2** from the GitLab downloads page.
    - Do not complete any other steps on the download page.
 
+1. Make sure to collect [`CONSUL_SERVER_NODES`](database.md#consul-information), which are the IP addresses or DNS records of the Consul server nodes, for the next step. Note they are presented as `Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z`
+
 1. Edit `/etc/gitlab/gitlab.rb` and add the contents:
 
     ```ruby

doc/administration/high_availability/redis.md

@@ -754,28 +754,30 @@ gitlab_rails['redis_sentinels'] = [
 
 > [Introduced](https://gitlab.com/gitlab-org/omnibus-gitlab/issues/3786) in GitLab 12.0.
 
-  If you enable Monitoring, it must be enabled on **all** Redis servers.
+If you enable Monitoring, it must be enabled on **all** Redis servers.
 
-  1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
+1. Make sure to collect [`CONSUL_SERVER_NODES`](database.md#consul-information), which are the IP addresses or DNS records of the Consul server nodes, for the next step. Note they are presented as `Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z`
 
-     ```ruby
-     # Enable service discovery for Prometheus
-     consul['enable'] = true
-     consul['monitoring_service_discovery'] =  true
+1. Create/edit `/etc/gitlab/gitlab.rb` and add the following configuration:
 
-     # Replace placeholders
-     # Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
-     # with the addresses of the Consul server nodes
-     consul['configuration'] = {
-        retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
-     }
+   ```ruby
+   # Enable service discovery for Prometheus
+   consul['enable'] = true
+   consul['monitoring_service_discovery'] =  true
 
-     # Set the network addresses that the exporters will listen on
-     node_exporter['listen_address'] = '0.0.0.0:9100'
-     redis_exporter['listen_address'] = '0.0.0.0:9121'
-     ```
+   # Replace placeholders
+   # Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z
+   # with the addresses of the Consul server nodes
+   consul['configuration'] = {
+      retry_join: %w(Y.Y.Y.Y consul1.gitlab.example.com Z.Z.Z.Z),
+   }
 
-  1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.
+   # Set the network addresses that the exporters will listen on
+   node_exporter['listen_address'] = '0.0.0.0:9100'
+   redis_exporter['listen_address'] = '0.0.0.0:9121'
+   ```
+
+1. Run `sudo gitlab-ctl reconfigure` to compile the configuration.
 
 ## Advanced configuration