Xen and the art of DNS
I’ve been following Xen, the newest of the Linux Virtual Machine (VM) technologies for awhile. I’ve been using UML to run a few services, mainly DNS and Nagios. Each has it’s own UML instance, which lives as a file on the hard disk of another machine. It means I can safely give access to these VM to friends without having to give them access to any real hardware. It also means if it gets screwed up, I just restore the file from my backups.
Xen works alot like UML, but you end up running a customized kernel on the host. This ‘hypervisor’ controls the resources of the host, and allocates/shares them to the guest VM’s as needed. It’s a pretty standard, boring architecture dating back to the 70’s and IBM mainframes. But Xen’s performance on x86 is much better than UML’s, and the ability to migrate a live VM from one physical piece of hardware to another is new and something I’d like to be able to do. It means I can migrate all the VM’s to another machine for 20 minutes while I upgrade the primary host, and no-one will notice.
Thanks to the Fedora Xen Quickstart guide, it was pretty painless to take a UML and move it over my Xen server. Just had to remember to edit /etc/fstab as the partition names change (/dev/ubd/0 -> /dev/sda1, etc…) and kill my static arp entires on the UML server.
First server migrated was, you guessed it, the DNS server. It’s now happily running on the Xen server, and I’m in the progress of moving over a web server and the nagios server. If I can cut out a few more physical machines, maybe I can even drop the hydro bill 
Tickets from the mail
I picked up our Alaskan Cruise tickets today, and the wedding bands.
We scored a deal from some place in Limeridge mall back in March, as they were going out of business, and in thier final days. So final, they wouldn’t be able to size them as they’d be closed by the time the resizing was done. We took them anyways, and I dropped them off Sunday to a local place to get resized.
Review: Joel on Software
I picked this up from the local Chapters, but you can order it online (Chapters.ca Link), and I really quite enjoyed it. Joel’s writing is excellent, he draws from his experience and gives an a good selection of anedoctes to back up his points. I’ve since lent my copy to my boss @ MDS, and she’s quite enjoying it. I just hope it get it back!
Joel’s got a kickass blog here, and I recommend if you have to deal with software development in any capacity (coder/manager/PM/IT) it should be required reading.
I orderd his next book (The Best Software Writing I), and it finally arrived today, prompting me to write this review.
Alex & Elena’s Wedding
Sunday we attended Alex and Elena’s Wedding up in Aurora. Great wedding, Sam and I broke out the Vodka early so I could have a good drive and still have time to sober up for the drive home.
Jason and I played with our Canon’s (he’s got a EOS 1D, the bastid) so here are my results http://ken.bantoft.org/gallery/gallery2/main.php.
It’s kinda fun having another photographer there I can swap parts with. We officially dubbed my 75-300mm lens as the ‘Porn Lens’ since you can do close ups from across the hall - it’s like spying on someone
T-40 and counting
It’s 40 days to the big day, and Van and I are pretty much set. Cheques written, everything booked, so now we’re just trying to relax and regain some sanity - it was a really hectic July for us!
Flickr Photos
