Jenkins is very slow on first visit

Question

Jenkins is very slow on the first visit in the early morning. This also happens if we restart the Jenkins server.

So the first developer accessing the jenkins has sometimes wait up to 3 minutes. We thought it was an issue with the build load. So we moved all build-jobs to a jenkins slave. But the issue has not been solved with it.

Since the performance seems to be always bad after restart. I assume jenkins reads a lot of stuff into memory. How can we enforce jenkins to precache stuff? We can give jenkins a hughe amount of RAM if needed. Hopefully the cache will solve the speed issues.

Answer 1

It would be difficult to definitively say what is causing your Jenkins instance to take so long to startup, though it is highly likely that one of your installed plugins is the offender.

For example:

1. JENKINS-17837 - Downstream Build View Plugin
2. JENKINS-24945 - Global Build Stats Plugin

Surely there are other plugins besides these two which have bugs/issues resulting in slow startup times as well. Some may have had issues and subsequent versions have addressed the performance issues.

Therefore, performing the following steps should at least reveal the culprit if not entirely fix the issue:

1. Upgrade Jenkins to the latest, stable version
2. Upgrade all plugins to their latest, stable versions
3. Restart Jenkins
4. If startup remains slow, remove your plugins one at a time (ensuring to save their respective configurations if necessary)

If upgrading to the latest versions does not improve your startup time, step 4 should reveal the culprit.