Linux

Debugging segfaults from logs to gdb

So this week after a version upgrade on GraphicsMagick we got some segfaults on our servers. Nothing terrible, twelve segfaults or close to that on a 24 hour period. The only information was a line on /var/log/kernel.log:

Feb 22 13:28:27 serverXX kernel: [1953364.275653] gm[16356]: segfault at 0 ip 00007fd137bd41e0 sp 00007fff5770dcd0 error 6 in libGraphicsMagick.so.3.7.0[7fd1379b9000+29d000]

No core dumps since ulimit -c is zeroed. What to do to at least have an idea of what is happening?

HoardD javascript support (and #monitoringsucks)

First things first: the latest revision of HoardD on github already supports scripts written in pure javascript. Really it was easy to make it work but I kinda overlooked it on the first version. The README.md is already updated. Second: most of you probably know the #monitoringsucks movement/hashtag/discussions. I totally agree that the current monitoring tools only do part of the job and getting them to work together is horrible. I have some ideas on how to solve the problem, but the path from idea to code is a long one.

Announcing HoardD

Getting back to work as a full time sysadmin was great, I got back to speed on scalability, updated my toolbox and learnt about other fantastic tools, like Graphite. Graphite is a graphing tool, extremely configurable and scalable. One thing, though, bothered me: the lack of good tools to send server metrics to it. I tried collectd graphite plugins and none did what I wanted the way I wanted.

So I decided to flex my node.js dev muscles and here is HoardD. This is a node.js app written in coffee-script that basically runs scripts and tools to get information about a server and sends it to carbon (Graphite’s storage backend). It’s easily expansible to include more metrics and very very fast and small (11MB or so, depending on scripts loaded, most of it is node).

Getting the correct name on Gnome 3 Chromium windows

Gnome 3 is awesome, by far the best user experience I ever had. It’s fast, does exactly what I need and has sensible defaults.

One problem that I had for some weeks – after some upgrade I am sure – was that Alt+Tab and Alt+(key below ESC) behavior with Google Chromium windows was completely annoying: all my browser windows, including the ones I use --app and a different data directory, were grouped under “Google Chromium” icon, like in this screenshot I took (click on it for full size):

Me and Linux

So, 20 years ago Linus was sending his now famous Usenet message about a new hobby. It’s a big date, 20 years and that went from a small project to what we have now and pretty much my only way to make money and live :)