Configuring JBoss Farming service

JBoss farming service was available for early versions of the application server. such as JBoss 4 and JBoss 5. This tutorial discusses how to configure it and which are the alternatives available for new versions of the application server.

What is JBoss Farming Service?

The farming service is an hot-deploy feature available in the “all” configuration of the application server.

Using the farming service, you can deploy an application archive (such as a WAR, EAR, or SAR or even an exploded archive) to the all/farm/ directory of any cluster member and the application will be automatically deployed across all nodes in the same cluster.

If another node joins the cluster, it will pull in all farm deployed applications in the cluster and deploy them at start-up time. Much the same way, if you delete the application from an active JBoss cluster’s farm/ directory, the application will be undeployed locally and then removed from all other clustered server nodes’ farm/ directories.

It’s even possible to fine-tune the farming service by modifying the attributes of the farm-service.xml configuration file. This file is located in the deploy/deploy.last directory:

<bean name="FarmProfileRepositoryClusteringHandler"
      class="org.jboss.profileservice.cluster.repository.
      DefaultRepositoryClusteringHandler">
  
  <property name="partition"><inject bean="HAPartition"/></property>
  <property name="profileDomain">default</property>
  <property name="profileServer">default</property>
  <property name="profileName">farm</property>
  <property name="immutable">false</property>
  <property name="lockTimeout">60000</property><!-- 1 minute -->
  <property name="methodCallTimeout">60000</property><!-- 1 minute -->
  <property name="synchronizationPolicy"><inject bean="FarmProfileSynchronizationPolicy"/></property>
</bean>

partition is a required attribute to inject the HAPartition service that the farm service uses for intra-cluster communication.

profile[Domain|Server|Name] are all used to identify the server profile.
immutable indicates whether or not this handler allows a node to push content changes to the cluster.

lockTimeout defines the number of milliseconds to wait for cluster-wide lock acquisition.
methodCallTimeout defines the number of milliseconds to wait for invocations on remote cluster nodes.
synchronizationPolicy decides how to handle content additions, reincarnations, updates, or removals from nodes attempting to join the cluster or from cluster merges. The policy is consulted on the “authoritative” node, i.e. the master node for the service on the cluster. Reincarnation refers to the phenomenon where a newly started node may contain an application in its farm/ directory that was previously removed by the farming service but might still exist on the starting node if it was not running when the removal took place.

Advanced features

Since the release 5.1.0 of the application server the farming service is back and has got even better!

1# The farming service is available also for exploded directories.

In the 4.X release of JBoss the farming service was available only for archive deployment. With the new release you can safely deploy exploded deployments too.

jboss farming service 5.1.0

2# Optimized file transfer
In the release 4.X each time a new node joined the cluster, it received a copy of the content of the farm directory even if the application was already deployed on it. This needless operation has been eliminated in the release 5.1.0

3# Deploy and farming service are now synchronized
In the earlier release if you removed a deployment unit from the deploy folder and not from the farm directory, at next startup the application would have been redeployed again. Tbis has been corrected in JBoss AS 5.1.0

How to replace the farming service in WildFly

If you are running WildFly or JBoss EAP 6/7 the Farming Service is not available any more. The recommended way to distribute applications to your cluster using a single distribution point is to switch to Domain mode and use management instruments.

This way, you will be able to deploy/undeploy your applications to a Server Group in a similar way you used to do with the Farming Server, although you will be using Management Instruments such as the CLI and Web Console.