The number of JGroup threads is 200
by default.
While it can be configured using the property Java system property jgroups.thread_pool.max_threads
, we advise keeping it at this value.
As shown in experiments, the total number of Quarkus worker threads in the cluster should not exceed the number of threads in the JGroup thread pool of 200
in each node to avoid requests being dropped in the JGroups communication.
Given a Keycloak cluster with four nodes, each node should then have around 50 Quarkus worker threads.
Use the Keycloak configuration option http-pool-max-threads
to configure the maximum number of Quarkus worker threads.