I have some experience with Xen, but no experience with any software that controls a hypervisor. Wind River has several customers interested in using oVirt and Openstack with Wind River Linux. Another team is looking at oVirt, but no one had taken up the Openstack investigation. I have experience with Puppet and Puppetlabs has some official Openstack modules, so it seems a good place to start.
I re-purposed a coverage builder and installed Fedora 18. I had read about Openstack and Fedora and thought that would be a good place to start. Then Redhat announced the Packstack and RDO project and I decided to give it a try.
The initial install failed due to selinux being disabled and conflicts with NIS (our NIS deployment contains users with uids that conflict with the ones in the rpms). When I finally got the packstack installer to complete after a clean install, openstack refused to recognize the admin user. So I did a reinstall using CentOS 6.4 and everything worked without issue.
My experience with virtual machines has always been boot and install onto some empty, usually virtual, disk. Openstack was my first interaction with images. The docs recommend a base F18 image. The first attempt to download using the horizon interface seemed to hang. I was able to wget the image on my local machine 30 minutes after the download using the web page had started.
My initial install of the host OS created a large LVM partition called cinder-volumes for the Openstack Block storage service. Unfortunately, the packstack installer renamed the volume group. I had to:
I went into the Volume section of the Horizon Web UI and created a Volume. Running lvs on the host shows that a volume was created in the correct place. I launched the instance as tiny and noticed that it did not require a volume, which I found strange. I had setup a security group to allow ssh and inject my public key. I then associated a floating ip and was able to log into the vm! This was a happy moment.
After some poking around, a disk space check revealed that the VM had 10 GB disk space. This confused me because I had not associated it with a volume. So I repeated the process but setup the VM to boot off the volume I created earlier. This time the boot failed due to missing boot image.
I did more research and found this article. It explains some the history of virtual machine infrastructure. When EC2 was first launched, the VMs had no persistent storage. Customers had to use some sort of web service like S3 to persist information. This kind of image is called instance-store; Openstack refers to it as Ephemeral storage.
Then Amazon introduced EBS to provide persistent storage. It could be attached to an instance-store image as a another block device. In Openstack this is handled by Cinder as block level storage.
Then came the ability to boot from EBS volumes. This matches my internal model of a virtual machine as persistent like a physical machine. By default the volumes are empty, so the next step is populating the volume with the proper bits. I have experience with Cobbler to use kickstart and others to install new systems, but I was curious if the image could be “transferred” to the volume.
The Horizon Web UI was not helpful. Some more research revealed the following:
cinder create --image-id <image-id> --display-name mybootable-vol 10
This runs qemu-img convert and writes the raw image to the new cinder volume. This volume can be booted directly, but the Web UI still requires an image name which is ignored.
Types of Openstack VMs: 1) Ephemeral storage only. Default size of 0 means use image disk size. 2) Ephemeral + block storage. VM must format if blank and mount. Volume can only be attached to one VM. 3) Block storage only. Web UI does not support image to volume conversion but cinder does.
Next on my list is NetApp cinder driver and installation on Ubuntu 12.04 Server using official puppet modules.