CODEWITHSUNDEEP
javatomcatjvm
raghava
raghava

Reputation: 86

How jvm distributes between tomcat and deployed Java applications

We have Tomcat deployed with two Java based web applications. How can I tune the performance of one of the applications without affecting the other one if they are running in the same JVM?

Upvotes: 1

Views: 1298

Answers (2)

Khanna111
Khanna111

Reputation: 3931

The two web applications are deployed within the same JVM (including tomcat). So there is just one JVM that tomcat and the two web applications reside in. This is your current scenario.

On the other hand if you would like to tune the web applications separately - say in terms of performance etc. then the easiest thing would be to deploy them on two different hosts / machines. This way the two web applications would be running in their own JVM and would be completely isolated from each other and can be tuned independently. Note: you would need to think this through in terms of requirements of another host and yet another for a reverse proxy. See EJP's comment below.

If that is not possible then you could have two different JVMs brought up each with a tomcat and one of the web applications. This way you could tune the two JVMs separately: you could tune the tomcat servers running separately within the two different JVMs, you could attempt to run them with different allocations of OS resources etc. But that is an involved topic for another discussion. How would you achieve two different JVMs running a tomcat and one of the web application each? To achieve that you utilize the CATALINA_BASE approach wherein the two web applications are deployed to two differently located "webapps" folders. I will not go into details on this but leave you with a link. Note: you might need a reverse proxy as well in this case.

With the two different JVM approach (two different java processes), the respective JVMs can be tuned separately. I prefer this approach as this way it is easier to have separate things like log configurations, restart one without affecting the other and so on.

Since you are talking about performance, let me also mention in passing that whatever approach you might take, keep in mind that that in certain Operating Systems especially linux, you could restrict or allocate resource such as cpu, memory etc. to a particular process (JVM in your case). You could also utilize containers such as Docker to do the same. Maybe you are already aware of this, but I mention for completeness.

you can refer to: tomcat - CATALINA_BASE and CATALINA_HOME variables

Upvotes: 1

grebesche
grebesche

Reputation: 511

Your tomcat run in a JVM with both your applications. All 3 run in the same JVM. So if you tune the JVM (like max memory usage), everything will be affected by it. As far as I know there is no ways to indicate that you want more resources allocated to 1 of your applications.

Upvotes: 2

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