Jenkins

We have recently started using Jenkins at work and it is awesome.

Jenkins describes itself as a continuous integration software, but it really is more. You can use Jenkins to build, test, and do cron jobs, etc. It’s very powerful and really useful.

Not only is very useful, it is being developed and improved quickly. Bugs get fixed rapidly by a very motivated team of developers. Combined with its extensive list of plugins, Jenkins becomes amazingly useful in a variety of situations.

Jenkins’ main unit of work is a ‘job’. While it obviously has a preference for Maven jobs, it works very well with so-called “free-style” jobs; jobs that use arbitrary commands.

Jobs can be triggered on SCM changes, cron specifications, the creation of a file, a URL changing, or anything a plugin might add. For example, we trigger builds for some jobs based on Gerrit changes allowing us to test changes before they enter git’s master branch.

The support for kinds of activities that can be performed is amazing: Unix shell, Windows cmd, jPython, JRuby… just to name a few.

I’m contemplating replacing my cron jobs with Jenkins on Gerf.Org just because it is so much handier to be able to look at logs, re-trigger a cron job, etc. Not to mention that I can use it for continuous integration of IATed and any other projects I want.

Jenkins has great support for slave nodes. Out of the box it supports Unix slave nodes via SSH; it will automatically connect to the slave and setup the correct JDKs, etc. all on its own. Even setting up a windows slave is relatively easy: Install a JVM, go to the Jenkins page for that slave node and web-launch the slave software; it does the rest. To make the slave permanent across re-boot, use the menu option in the slave program to install it as a service. Not as easy as with Unix, but still very easy.

If you want to try it out, you can get it running really quickly by running java -jar jenkins.war… it has a built in servlet container server. Or you can try the docker container.

Overall, I give Jenkins two thumbs up.

Ciao!