This article shows you how to install a gem (a ruby package) that provides access to Amazon APIs for EC2, ELB, and RDS. But along the way it also provides important information on the entire Rubygems environment. This information is critical for anyone who is tasked with maintaining a working Ruby environment.

Yesterday I posted an entry about using Ruby to access the Amazon EC2 API and I mentioned a gem that provided the classes needed to make such access easy. Gem is the package system for ruby, and fills a role similar to one that CPAN provides for perl. The Amazon gem is called amazon-ec2 and it is written and supported by Glenn Rempe.

I've been recently extolling the virtues of Ruby on the Lopsa IRC channel so I thought it would be fun to take a real world problem and write a Ruby-based solution. This particular problem has to do with manipulating snapshots in Amazon's EC2. Those who administer EC2 instances know (or should know) that the storage associated with an instance does not outlast the instance. If you want persistent storage you have to create a volume of elastic block store. Not only will it outlast the instance, it can be moved between them and it can be backed up into something called a snapshot.

On most of our instances we have a cron job that creates a snapshot of

Recently I was building a ZenPack for Zenoss. The ZenPack included an Event Command which executed a custom script. I wanted to store the custom script in the ZenPack and I didn’t want to do anything other than have proper script dependencies in place for it to work. (Read More)

Monitoring and analyzing performance is an important task for any sysadmin. Disk I/O bottlenecks can bring applications to a crawl. What are IOPS? Should I use SATA, SAS, or FC? How many spindles do I need? What RAID level should I use? Is my system read or write heavy? These are common questions for anyone embarking on an disk I/O analysis quest. Obligatory disclaimer: I do not consider myself an expert in storage or anything for that mater. This is just how I have done I/O analysis in the past. I welcome additions and corrections. I believe it’s also important to note that this analysis is geared toward random operations than sequential read/write workloads.

I thought I would write a little about Office 2010. I realize this isn't about Windows, but Office is important too. I really think that Microsoft messed up the user interface on 2007, and I know a lot of people that feel the same way. Granted, they were looking to improve the user experience, and they primarily had the new user in mind. But what about the literally millions of users that they left behind?

Well, it looks like the interface has been improved further for 2010. The ribbons are still there, but at least it appears to look a little bit more like the 2003 interface than 2007 did. One aspect of 2010 that really gets me excited is the Office Web piece! This looks like it might be the start of a beautiful friendship between a lot of new users and Microsoft, especially because the web access is free to everyone. It includes the abiliy to store documents online so the user can access them from any computer that has access to the Internet.

In my last post I gave some first impressions using bcfg2. We ended up selecting bcfg2 as our configuration management system for a new project. I'm going to start with the "bad" and get that out of the way.

The bad

The biggest problem so far is getting the entire team up to speed on bcfg2. It's very different from what we're used to with cfengine2. One challenge is wrapping your mind around what I think is one of the basic tenets of bcfg2 - you specify everything twice. Let me explain: bcfg2 separates out configurations into an abstract specification, and a concrete implementation. For example, you may decide a certain group needs an /etc/motdfile. So in the abstract configuration (called a Bundle), you simply say: <Path name='/etc/motd'/>. This is great for easily seeing what should be there. However, it gives no clue as to where that file comes from. It could come from the plugin that distributes static files, or one of the plugins that parses templates and distributes the results.

I picked up a couple of the new WD Green 1.5TB drives recently. I needed some new storage, and these drives have a lot going for them:

- 64MB cache - low power usage - 4K sector size

I knew going into this that the 4K sector size was proving problematic in some circumstances. In short, these drives have a 4K physical sector size, but present 512B logical sectors for better BIOS/OS compatibility. All well and good, except this can cause partitions to be misaligned and lead to writes falling across different physical sectors. This article discusses some of the performance implications. I verified on my drives that properly aligning the first partitions does lead to >3x performance increases.

Anyone who has ever administered a Cisco Unified Communications Manager (AKA Call Manager, or CM) system learns very quickly that there are approximately 17 billion different configuration settings in CM. All of those configuration dials have to be maintained in the right ways to get the system to do what you want.

I've taken several Cisco training courses on CM, and I felt like the thing that was missing was a real-world case study of how you setup all the pieces to interact with each other and why. There was no real "best practices" in the classes, just a lot of "this setting does X or Y" without any explanation of why you would choose to do X vs Y.

Read on for exactly that information from documentation I've been working on for the CM environment at my job.

I'm teaching on LDAP at SCaLE U today, so I've uploaded my slides in advance.

At $WORK, we currently use cfengine 2 to manage on the order of 300 systems. It works, it does most things we want. We use the Singlecopy Nirvana "pattern" to distribute configuration files of all types, have copious shellcommands, and even a few editfiles. In general, it does what I need, but not necessarily the way I want. The general structure of our cfengine configurations is (for the most part) unchanged since I implemented it ~4 years ago. We've done the necessary things to support new OS's, new architectures, what have you, but that's about it.