WildFly supports clustering out of the box. There are several libraries that work together to provide support for clustering. The following figure shows the basic clustering architecture adopted by WildFly:

The JGroups library is core to WildFly clustering. It provides the communication channels between nodes of the cluster using a multicast transmission. These channels are created upon deployment of a clustered application and are used to transmit sessions and contexts around the cluster.

Another important component of clustering is Infinispan. Infinispan handles the replication of your application data across the cluster by means of a distributed cache.