What results from this resistance is that when your average developer decides he wants to monitor CPU usage or disk space on his machine he or she ends up doing it in the most obtrusive way possible – SSH. While I’m a big fan of small shell scripts, this is one place they do not belong. Let me give you an example:

I set up a new server here in London for one of our Chicago teams. Being a conscientious team, the first thing they did was wire in some monitoring that wrote for their servers. It checks things like disk space, memory usage, CPU load and the state of various processes that they care about. They need pretty fine grained checking intervals, so they check these every minute. The easiest way they know how to do this though is to SSH in to their machines and run df, free, netstat,etc and scrape the output. Every minute. Which on this nice shiny server consumed almost 20% of the CPU right off the bat. Educating them on the use of SSH ControlMaster helped, but it’s still doing a lot of work on the machine.

This was the last straw that lead to the creation of Ecks. People will always follow the path of least resistance, so if you want people to do the right thing, you need to make it the easiest thing to do. SNMP has all this information available, modern snmpd implementations are stable, have a tiny footprint and are more secure than providing SSH access to your machine.

The hardest part of all though is what to name this little library. When discussing the problem with Julian Simpson (the @builddoctor), he pointed out that MIB always reminded him of the Men in Black. Reading the Wikipedia article on the original comic book series had some interesting snippets:

The Men in Black are a secret organization that monitors and suppresses paranormal activity on Earth…

Replace “Earth” with “a computer” and you’re starting to get somewhere. Then I noticed this gem:

 An agent named Ecks went rogue after learning the truth behind the MiB: they seek to manipulate and reshape the world in their own image by keeping the supernatural hidden.

Many people think that the complexity of the MIB keeps SNMP data hidden. And so the name was chosen…

It’s by far the longest article I’ve ever written, and I was amazed at how ideas that had been floating around in my head for a while crystalized through the processes of writing them down. I found I got so passionate talking to people about what was in it that I’ve decided to make a talk out of it, the first iteration of which will be in Chicago on Tuesday (see previous post).

HTTP Request Returned 401 Unauthorized: Failed to authenticate!

A quick sift through Google results didn’t get anything usable. A quick sniff of the packets going over the wire though showed that it was authenticating using a signed certificate. Normally when you sign HTTP requests like that you add some kind of timed expiry. Could the problem be clock related?

Sure enough, a quick check on the new client and the server showed that there was just over an hour time difference. Getting the time on the client and the server in sync got the client registered!

With this in mind it was decided to call the conference DevOpsDays. Videos of the talks will be online in the archives section soon, so I’ve decided to write down my thoughts about what went well and not so well – I am a fan of retrospectives.

What Went Well

The conference was in Ghent, a city in Belgium, and as expected had quite a heavy European contingent. It was not not exclusively so though, as Reductive Labs and Canonical both sent representatives over from the USA, and one of the speakers is an Aussie who just happened to be back packing around Europe at the time. One of my first great learnings though was that there are about 10 of us in the greater London area who are doing this kind of thing (2 of them ex-TWers) so we’ve started meeting regularly and exchanging ideas.

As there was such a large concentration of us around London, we’ve decided to try and subvert one of the London Geek Nights as a DevOps night to try and spread the word to more Devs. I’ll probably make more noise about it here when we’ve got dates confirmed.

The next great thing I loved was the format. It was split up into talks in the morning, with Open Spaces in the afternoon, over 2 days. This format actually worked very well as many of the open space sessions were inspired by the talks. Another interesting mix was that there was an even split between talks on tools and talks on practices.

I also discovered some great tools! Here’s a brief list of ones I liked the most:

• The Marionette Collective – using a message bus to administer 100′s of servers using pub/sub topics. You’ve got to watch the video to appreciate the full awesomeness.
• Cucumber-Nagios – writing tests to monitor your system using Cucumber, and then formatting the results as a Nagios plugin so you can easily wire it in to your monitoring system.
• Flapjack – another example of interesting use of a message bus. This time to parallelize the monitoring of 100′s of servers. I’m not sure I totally agree with the approach, but what really blew me away was they way they do graphing and reporting. It’s very impressive.
• collectd – collectd gathers statistics about the system it is running on and stores this information in RRD databases. One of the things I really like about this though is that there are plugins for it like Jcollectd which requires no code changes. Simply plug it into your classpath and it registers a JMX MBean that pumps data from your JVM to collectd (I think). I’ve not tried it in production yet though…

Overall the conference was very well received, and I’m looking forward to next years instalment. There’s a lot of talk about doing a North American version…

Not So Well

As we all know, the best bits about Away Days/Conferences are the talks in the hall between sessions. The problem with the program was that we barely had enough time for bio breaks between sessions, and everyone was quite burned out at the end of day two (not just because of the Belgian Beer). I think it’s a pretty easy thing to fix though and considering that it was the first conference of its type there’s bound to be some fine tuning required.