When setting the property org.kie.server.sync.deploy to false (default value), all pre-defined containers are installed synchronously on startup as shown in the following call stack :

This is required for KIE Clusters with KIE Servers managed by KIE Server Controller deployed in a Kubernetes Cluster with liveness and readiness probes configured on KIE Servers to the healthcheck and readycheck endpoint. The KIE Controller ping will fails because the startup sequence is not completed and mark the KIE Server as offline.

It is critical to be able to deploy containers asynchronously and have KIE server ready to serve requests that do not not mandate container being ready (e.g. liveness or readiness probes request in a Kubernetes deployment).