Xen Hosting

Posted by paul on January 3, 2007.

I recently made the decision to move from a shared hosting account to a dedicated server. I was very happy with my shared hosting provider (WebFaction) but it’s not uncommon for me to have several websites or trac wikis or subversion repositories all going at once. I need these to be accessible to me and my clients at all times and my home DSL connection just isn’t dependable enough for hosting. I started looking into dedicated hosting packages but decided to save myself about $80 / month and go for a VPS (Virtual Private Server) package.

When it comes to virtualization, I'm a pretty big fan of Xen. If anyone is interested in the subject and hasn’t already, it’s really worth checking out. At a really high level, here’s how it works: basically you have a DOM0 (Domain-0) patched kernel that you run on your physical machine which you allocate a specific amount of RAM to. Once you have your DOM0 set up correctly you can install any number (RAM permitting) of guest hosts running a DOMU (unprivileged domain) patched kernel. You specify how much RAM you want to allocate to each DOMU and there are a number of ways to handle filesystems. The DOM0 (host OS) manages access to hardware and other low-level stuff and basically makes it completely transparent when working within a DOMU. It comes with some handy userland tools to manage guest hosts and there are 3rd party packages like enomalism (Yes I just plugged my former employer!) that make it really simple.

So I started shopping around for hosting companies offering VPS packages that used Xen and I found one that looked a little nickle and dime, but were local, had reasonable prices and offered my favourite Linux distribution (Gentoo!). I figured I’d give them a shot. One week and 14 hours of downtime later I canceled my account, got a refund and signed up for an account with RimuHosting. Now these people know how to do support! Within minutes of signing up I got an email with a link to setup my PayPal subscription. I setup my subscription and less than an hour later had my account details. First things first, I tried to connect to my host via SSH and got a timeout... good opportunity to try out their support! I emailed their tech support and we were able to figure out that the problem was a lack of a reverse DNS entry on the VPS' IP address. I didn’t know that Mac OS X won’t open an SSH connection in these circumstances. Okay, easy to solve... there’s a handy utility in their control panel to do just that. Once that was working I was up and running and started to set up Apache, Postfix and all the other wonderful software I use.

Now I’m happily hosting several websites (each with MySQL or PostgreSQL databases), Trac wikis, SVN repositories, I’m running AWStats, hosting my mail, and generally loving the VPS life, all for at least a 5th of what a dedicated package would cost!