ELCCR-1528 Update user documentation with new arbiter feature

Change-Id: I765191290f5a14f9d2bb2495dfe8ccbd8180e6fb
Signed-off-by: Toma Bilius <toma.bilius@enea.com>

1 files changed, 12 insertions, 2 deletions

diff --git a/doc/book-enea-edge-getting-started/doc/advanced_configurations.xml b/doc/book-enea-edge-getting-started/doc/advanced_configurations.xml
index 18c1545..2f34153 100644
--- a/doc/book-enea-edge-getting-started/doc/advanced_configurations.xml
+++ b/doc/book-enea-edge-getting-started/doc/advanced_configurations.xml
@@ -417,9 +417,9 @@ node0.1048576kB = 3 </programlisting>
     </section>
   </section>
 
-
   <section condition="hidden" id="high_availability_ig">
-    <title>Installing the Enea Edge Management in High Availability Mode</title>
+    <title>Installing the Enea Edge Management in High Availability
+    Mode</title>
 
     <para>The following describes the setup needed for running the Enea Edge
     Management in High Availabilty (HA) mode, with a MariaDB database cluster.
@@ -927,6 +927,8 @@ Is this server part of a cluster? [Y/N]: <emphasis role="bold">Y</emphasis>
 Specify the name of the cluster [ucpemanager]: 
 Specify the shared (virtual) cluster IP address: <emphasis role="bold">192.168.10.10</emphasis>
 Specify the netmask for the cluster IP address [255.255.255.0]: 
+Specify the IP address of the (optional) arbiter: <emphasis role="bold">192.168.10.13</emphasis>
+Specify the port associated with the (optional) arbiter [3306]: 
 HA Configuration files modified successfully.
 Configuration complete.</programlisting>
 
@@ -938,6 +940,14 @@ Configuration complete.</programlisting>
           communicating with the database.</para>
         </note>
 
+        <para>The arbiter IP and port are used to mitigate split brain
+        situations. Providing an empty arbiter IP implies that no arbiter
+        checking is enabled - in other words, it implies that arbiter
+        connectivity is not checked. It is highly recommended to introduce an
+        arbiter to help with split brain scenarios. For instance, one of the
+        MariaDB cluster nodes can be used, with the default port
+        <literal>3306</literal> (the MariaDB listening port).</para>
+
         <para>Once the servers are up and running, log into the <emphasis
         role="bold">Primary</emphasis> and go to <emphasis
         role="bold">System</emphasis> and select <emphasis role="bold">Cluster