Issue
I have a Jenkins server hosted, which has a master node and couple of other slave configurations. Last night, the job that triggers the matrix based build configuration failed. I did a restart and performed clean up jobs via Jenkins but none of those fixed the issue. The initial error that was logged was:
FATAL: hudson.remoting.RequestAbortedException: java.io.IOException: Unexpected termination of the channel
hudson.remoting.RequestAbortedException: hudson.remoting.RequestAbortedException: java.io.IOException: Unexpected termination of the channel
Following which I performed a reload configuration from disk,followed by a manual restart via <jenkins_job_url>/restart, which even worsened the build system. The master went offline due to unavailability of space in /tmp folder, which I fixed by cleaning up the space. Following which I observed that the original slave server configuration is no longer seen. I had slave-0 and slave-1 still there, but slave-2 was no longer present. Instead, it got replaced with slave-3 configuration. Now the slave 0's and 1's seems to be working fine. However, slave 3's build are failing due to Failed to mkdirs. Is there a way I could revert back to the original configuration from where I started, since the steps I performed seems to make sense initially, but I had no idea it had so many repercussions? Any help is appreciated.
UPDATE1: I guess I should have used some of the configuration backup plugins available in Jenkins, but is there some specific directory other than $JENKINS_HOME where these configurations gets stored?
Solution
You should always backup ${JENKINS_HOME} before doing major changes.
Even better is to have a job based on time trigger that will do this for you once in a while.
Other than that - only physically restoring the hard drive to a previous state will get back your old configs. Once a config is overwritten in Jenkins - it is gone. Except when you are using Job Config History plugin. Though keeping manually created backups is better in my opinion: where's the insurance that JobConfigHistory won't disappear along with the job configs? :)
Aside from that, the mentioned plugin tracks system config too.
Answered By - Zloj
