[dkhenry]

You can also spin up Tomcat with everything needed to run an application with your local package manager and you can deploy your WAR file by putting it in the right location, but that's not what IBM, Oracle, and Red Hat have sold as Application Servers.

This is effectively what is being sold now but using Kubernetes and Containers instead of Application Servers and J2EE

[derefr]

The difference is that Tomcat can’t run arbitrary badly-behaved third-party x86 binaries under itself. (I mean, it can, but it doesn’t have the facilities to protect itself from them.)

K8s lets you build “containers” out of whatever existing software happens to be laying around, rather than having to write your services from the ground up for being run in a container.