Month: November 2014

Pain often equals Progress

It has been one of those weeks.  Not fun, to many hours worked, personal events missed, you know the kind of week I am talking about.  If not…what do you do for a living?!

Despite all the pain and stress this week has resulted in Progress, an increased understanding of certain products and new ways to use old tools.  I won’t share the details of my story, just insert yours here, but I will share/document the lessons and commands I learned or rediscovered.  Here we go…

Starting a long running process from home last night around 9PM and forgetting to start screen…priceless!  At 5:30AM this morning the process was still chugging along, with from my calculations would be running for another 18+ hours.  Off to work with no way to grab the terminal (an ssh session), what to do?  Why use strace of course!  Here is how:

strace -pPROCESS_PID -s9999 -e write

ie: strace -p3918 -s9999 -e write

Now even if my ssh session dies at home, I can still see the process output and know when it finishes and if it had any problems.  Yes, I could have piped output to a file, you never forgot anything after working for 15+ hours?

Dealing with a system that had some package inconsistencies and a yum update that failed, followed by a package-utils –cleandupes that erased many complete packages, I thought about using the ‘yum history’ command to revert the system until I read this: “Use the history option for small update rollbacks.”  Here are some of the commands I used which due to the systems package inconsistencies did not perform as expected.

# yum check
# package-cleanup --cleandupes
# yum-complete-transaction
# yum check
# package-cleanup --problems
# rpm -Va --nofiles --nodigest
# yum distribution-synchronizatio

The rest is pretty standard stuff, at least not worth noting in this post.  The end result this week is a lot of lessons learned and a much deeper understanding for an application that I support on my server.  In all, ignoring the backlog, I’d say that is what progress looks like.