Author: Romain Pelisse

For decades now, software projects have relied on messaging APIs to exchange data. In the Java/Java EE ecosystem, this method of asynchronous communication has been standardized by the JMS specification. In many cases, individuals and organizations leverage Red Hat JBoss Enterprise Application Platform (JBoss EAP) to act as message-oriented middleware (MOM), which facilitates the management of message queues and topics.

Messaging ensures that no messages are lost as they are transmitted from the client and delivered to interested parties. On top of that, JBoss EAP provides authentication and other security-focused capabilities on top of the management functions.

When it comes to Java web servers, Apache Tomcat remains a strong favorite. Some of these instances have been containerized over the years, but many still run in the traditional setup of a Linux-based virtual machine or even on bare metal.

Red Hat JBoss Web Server (JWS) combines the servlet engine (Apache Tomcat) with the web server (Apache HTTPD), and modules for load balancing (mod_jk and mod_cluster). Ansible is an automation tool that provides a suite of tools for managing an enterprise at scale.

In this brief demonstration, we’ll set up and run three instances of WildFly on the same machine (localhost). Together they will form a cluster. It’s a rather classic setup, where the appservers need to synchronize the content of their application’s session to ensure failover if one of the instances fails. This configuration guarantees that, if one instance fails while processing a request, another one can pick up the work without any data loss. Note that we’ll use a multicast to discover the members of the cluster and ensure that the cluster’s formation is fully automated and dynamic.

Install Ansible and Its Collection for WildFly

On a Linux system using a package manager, installing Ansible is pretty straightforward:

In this follow-up to Automate and deploy a JBoss EAP cluster with Ansible, we will explain how to maintain and keep those instances updated, again in a fully automated manner, leveraging Ansible and the Ansible collection for Red Hat JBoss Enterprise Application Platform (EAP). 

Indeed, it is critical to ensure that all JEE application server instances always be up to date, especially in regard to security fixes. Therefore, we’ll discuss not only how to apply patches to update the server but also how to perform an upgrade to migrate to a new major version.

The article Deploy Keycloak single sign-on with Ansible discussed how to automate the deployment of Keycloak. In this follow-up article, we’ll use that as a baseline and explore how to automate the configuration of the Keycloak single sign-on (SSO) server, including setting up users, specifying LDAP connection details, and so on.

Here again, to facilitate our automation, we will leverage an Ansible collection named middleware_automation.keycloak, specifically designed for this endeavor. 

According to several sources we queried, more than 33 percent of the world's web servers are running Apache Tomcat, while other sources show that it's 48 percent of application servers. Some of these instances have been containerized over the years, but many still run in the traditional setup of a virtual machine with Linux.