Jenkins bump from 1.x to 2.x

Jenkins is one of the amazing open source softwares especially after it forked itself from its predecessor Hudson. Amazing for multiple reasons - but the one that has really "amazed" me is the painless upgrades it provide. Trust me, I am a Rails developer and I know in & out on what a nightmare it is to perform an upgrade!

Recently I had to perform an upgrade for Jenkins and it was as dead simple as replacing a .war file and I was err.... DONE! All I did was stopped and started the process whilst replacing the war file. Once I rebooted, it all just worked. They seriously think about making their installations to run the latest software which I personally consider a true value.

Anyways, the reason me posting this is to help my fellow developers who are running into an issue where their slave would not start up after the upgrade process.

You would face an error something like this below when you go and inspect in the slave agent.

What this error means is that it could not invoke the slave because of an outdated java running in the slave. All you've got to do is upgrade it and you should be all good to go.

This was how the overall upgrade felt like :)

Cheers!
Braga