I have included a brief summary of product stack that we are working on and the required migration to cluster setup.
For the application that we are working on, we have the following components running on a single instance of RHEL 8.2 server to be migrated to a cluster environment
* Middleware - Wildfly 20
* Database - PostgreSQL 12 with PostGIS 3.0
* GeoServer hosted on Tomcat 9
* Filesystem data
* Standalone scripts that are invoked from application hosted on wildfly
* Python REST services hosted on Flask / Uvicorn
We came across Pacemaker (as part of RHEL HA) and related packages that can be used to configure them as resources
Also, we need the cluster nodes (more than 2) to be spread across WAN (with high bandwidth). We will have 2 different LANs connected with a high speed WAN. Both LANs will have some nodes of the cluster. From the client browser, with the virtual IP, user can access web application hosted by wildfly that can access other components mentioned above.
We also need a DR setup at a distant location that can be used when the cluster across 2 LANs has failed completely.
For HA Clustering, we are exploring RHEL Pacemaker, PostgresSQL + Patroni, Solr Cloud, Wildfly + JGroups