Docker Clustering multiple proxies fronting multiple tomcats

I want to move a cluster of application servers fronted by proxies to a Kubeetes Docker environment. We now have a failover crossed clustering like cluster and we are using sticky sessions to limit resources needed for our memory prone solution (>2GB each Tomcat).

I am now struggling with the concept of each component as microservice. Both microservices (Proxy/Tomcat) should scale independently as needed. Also considering self healing of a service with a minimum of 2 containers. Each container should be agnostic eg: unaware of its surroundings, it provides a service to another component.

Now how would a proxy container binds itself to all underlying tomcat containers? How could a proxy container binds whit a tomcat container added/resurrected later than this proxy container started? Now how would a proxy container maintain stickyness to a specific tomcat container?

I purposely tried to keep question and description as minimal as possible, happy to give more details of course.

Regards, Coé