The blog post by Matthew Casperson explores the process of configuring a cluster of WildFly instances in an AWS environment by extending the use of a WildFly domain. The author distinguishes between a domain, which is a management tool, and a cluster, which allows sharing of Servlet session state across multiple WildFly instances. The configuration utilizes an Aurora MySQL-compatible database for cluster node discovery and involves setting up a JGroups stack with TCP and JDBC_PING protocols to replace the default UDP and multicasting, which are not supported by AWS. The article also discusses the necessity of a centralized load balancer for distributing web requests evenly across cluster nodes, ensuring session persistence even if one node fails. Additionally, the author provides steps for deploying a distributable web application and verifying the cluster configuration by checking session data replication across nodes, highlighting the importance of session continuity in a clustered environment.