computing – Made by Mikal

Further adventures with base images in OpenStack

Post author:mikal
Post published:January 4, 2012
Post category:OpenStack

I was bored over the New Years weekend, so I figured I'd have a go at implementing image cache management as discussed previously. I actually have an implementation of about 75% of that blueprint now, but its not ready for prime time yet. The point of this post is more to document some stuff I learnt about VM startup along the way so I don't forget it later. So, you want to start a VM on a compute node. Once the scheduler has selected a node to run the VM on, the next step is the compute instance on that machine starting the VM up. First the specified disk image is fetched from your image service (in my case glance), and placed in a temporary location on disk. If the image is already a raw image, it is then renamed to the correct name in the instances/_base directory. If it isn't a raw image then it is converted to raw format, and that converted file is put in the right place. Optionally, the image can be extended to a specified size as part of this process. Then, depending on if you have copy on write (COW) images turned on or…

Openstack compute node cleanup

Post author:mikal
Post published:December 20, 2011
Post category:OpenStack

I've never used openstack before, which I imagine is similar to many other people out there. Its actually pretty cool, although I encountered a problem the other day that I think is worthy of some more documentation. Openstack runs virtual machines for users, in much the same manner as Amazon's EC2 system. These instances are started with a base image, and then copy on write is used to write differences for the instance as it changes stuff. This makes sense in a world where a given machine might be running more than one copy of the instance. However, I encountered a compute node which was running low on disk. This is because there is currently nothing which cleans up these base images, so even if none of the instances on a machine require that image, and even if the machine is experiencing disk stress, the images still hang around. There are a few blog posts out there about this, but nothing really definitive that I could find. I've filed a bug asking for the Ubuntu package to include some sort of cleanup script, and interestingly that led me to learn that there are plans for a pretty comprehensive image management…

Looking for Women studying computing in Australia

Post author:mikal
Post published:September 7, 2006
Post category:Google

I was in an unrelated meeting at work today, and it came up that the first annual Anti Borg scholarship is closing it's application window in a few days. I thought it was worth mentioning here, in case there are people who are interested in applying. The basic deal is: Dr. Anita Borg (1949 - 2003) devoted her adult life to revolutionizing the way we think about technology and dismantling barriers that keep women and minorities from entering computing and technology fields. Her combination of technical expertise and fearless vision continues to inspire and motivate countless women to become active participants and leaders in creating technology. As part of Google's ongoing commitment to furthering Anita's vision, we are pleased to announce the 2006 Google Australia Anita Borg Scholarship. Through the scholarship, we would like to encourage women to excel in computing and technology and become active role models and leaders. Scholarships will be awarded based on the strength of candidates' academic background and demonstrated leadership. A group of female undergraduate and postgraduate student finalists will be chosen from the applicant pool. The scholarship recipients, selected from the finalists, will each receive a $5,000 AUD scholarship for the 2007 academic year.…