How configure Wildfly 11 in HA Mode with preferred master?

[lucianoborges]

I am currently using the default HA configuration in Wildfly 11. I would like to know how can I tell which particular cluster is preferred if it is available.

I believe I should change the singleton subsystem but I do not know how.

        <subsystem xmlns="urn:jboss:domain:singleton:1.0">

            <singleton-policies default="default">

                <singleton-policy name="default" cache-container="server">

                    <simple-election-policy/>

                </singleton-policy>

            </singleton-policies>

        </subsystem>

EDIT

Run ./jboss-cli

Run the command: /subsystem=singleton/singleton-policy=default/election-policy=simple:write-attribute(name=name-preferences,value=[node3,node2,node1])

The standalone-ha.xml was altered to:

<subsystem xmlns="urn:jboss:domain:singleton:1.0">

     <singleton-policies default="default">

          <singleton-policy name="default" cache-container="server">

               <simple-election-policy>

                    <name-preferences>node3 node2 node1</name-preferences>

               </simple-election-policy>

          </singleton-policy>

     </singleton-policies>

</subsystem>

Now I'd like to know what is the name to put in place of node3, node2, node1.

How to define the name from my node?

[pferraro]

The node name is the value returned by:

/core-service=server-environment:read-attribute(name=node-name)

This value defaults to the hostname of the server.  You can override this via the "jboss.node.name" system property.

[lucianoborges]

Step 1: Edit the standalone-ha.xml from the master server and enter a name attribute in the tag below:

<server name="master" xmlns="urn:jboss:domain:5.0"> 

Step 2: Edit the standalone-ha.xml from the slave server and enter a name attribute in the tag below:

<server name="slave" xmlns="urn:jboss:domain:5.0"> 

Step 3: Edit the subsystem singleton in both servers like below:

<subsystem xmlns="urn:jboss:domain:singleton:1.0"> <singleton-policies default="default"> <singleton-policy name="default" cache-container="server"> <simple-election-policy> <name-preferences>master</name-preferences> </simple-election-policy> </singleton-policy> </singleton-policies> </subsystem> 

When the master drops then the slave takes over, but when the master get up it reassume the command.

[pferraro]

The purpose of the singleton subsystem is not to manage servers.  That is the responsibility of the domain controller.

The singleton subsystem is used for installing singleton MSC services and singleton deployments.

Read more about that here:

wildfly/Singleton_deployments.adoc at master · wildfly/wildfly · GitHub