Should You Deploy Multiple Apps on One Tomcat? Pros, Cons & Best Practices

Should multiple applications be deployed to the same Tomcat instance, or should each application have its own Tomcat?

Below we compare the advantages and disadvantages of the two approaches.

Multiple apps in one Tomcat

Advantages:

Installation, management and monitoring are simpler because only one Tomcat needs to be handled.

Disadvantages:

All applications share the same JVM memory; a heavy‑weight app can cause frequent GC that pauses the others.

One Tomcat per app

Advantages:

Memory is isolated; a crash or GC in one app does not affect the others.

Disadvantages:

Installation, management and monitoring become more cumbersome; you can mitigate this by using separate CATALINA_HOME directories.

Operations perspective (multiple apps per Tomcat):

Saves memory footprint because each Tomcat instance consumes memory even when idle.

Reduces filesystem overhead (logs, temp directories, installations).

Avoids extra Nagios monitoring configuration.

Fewer ports to manage, simplifying security.

Only one set of security patches to apply.

Developers’ perspective (one app per Tomcat):

Faster startup when apps are isolated.

Problems in one app (OOM, thread exhaustion) do not impact others.

Diagnostic actions such as heap dumps, thread dumps, or CPU profiling can be performed without affecting other applications.

Community replies generally favor one‑app‑per‑Tomcat for simplicity, isolation, and the ability to use different JVMs, libraries, or environments without compatibility concerns. However, if applications are small and resource‑light, sharing a Tomcat can be acceptable.

Tomcat core developer Mark advises choosing the approach based on resource requirements: heavyweight apps merit dedicated Tomcat instances, while lightweight apps can share one for easier management.

In production, I prefer independent deployment and monitoring for each application, while in development a single Tomcat with multiple apps speeds up iteration.