每次重新启动tomcat服务时是否都需要部署war文件

Question

I have a couple of war files which were deployed and the web applications were working fine but every time the tomcat service or the system gets restarted the war files were getting redeployed and to stop the redeployment I set the configuration options deployOnStartup and autoDeploy to false in the server.xml.

But now after the machine restart or tomcat service restart, the web applications are not working, So I wonder if the war files need to be redeployed every time the machine or tomcat is restarted.

The original issue which I faced is that when tomcat deploys the war files on startup and restart it consumes up to 95% of CPU and the other processes are being held,so to solve it I tried to turn off auto deployment but if auto startup is turned off the web applications are not working. So I need to know if there is any way to restrict the CPU usage by tomcat.

Answer 1

This is the way servlet containers work: you cannot have an undeployed application that is being invoked when clients make requests. "Deploy" really means "start" in this case. There is no separate "deploy" step that only needs to happen a single time for the application to be available through the container. Generally, deploy-on-startup is exactly what you want to happen.

If you are having a problem because your applications take all the system resources when they start-up, then I think you need to spend some time re-evaluating your capacity plan. You are saying that "other applications are held"... presumably you mean that, while your web applications are being deployed, other applications on the same server are not responsive. That' because of all the activity the web applications are performing.

Well... if you need both the non-web-applications and the web-applications to be available at the same time, then it looks like you are going to need a second server (or a third, etc.).

You might also want to look at your web application and see what it's doing during startup. Perhaps it's doing more work than necessary, or perhaps it's doing that work in an inefficient manner ¹ .

Ultimately, this is going to come down to what services you need available and what hardware you have available. If the services aren't meeting your needs (eg availability) then you need to change one of the parameters (eg more hardware) until the service again meets your needs. Or, you need to adjust your expectations (sorry... some services will just have to wait while the web apps startup).

¹ As a consultant, I once encountered a web application that could take up to 5 minutes to start and I got tired of waiting for it during our development efforts. So, I checked-out what was going on, and the application was building an in-memory representation of the entire relational database table and field structure. The way they had been doing it was horribly inefficient and, after a few hours of refactoring, I had reduced the startup time from ~5min to ~30sec. Sometimes, there's just a better way to do things.