Reading about VMWares Long Distance VMotion, which they offer in connection with Ciscos Data Center Interconnect, I was wondering if the same thing wouldn’t be possible using Citrix XenServer as well as OpenVPN. My current test setup is running a XenServer instance in Tubingen at my University, as well as an instance at the TU Munich. The distance between both locations is about 220KM, and a ping reveals a latency of about 8ms. Both locations provide a Bandwidth of about 100MBit through the Universities Internet connection, while throughput is limited by OpenVPN further. I got a Server running OpenVPN as well as NFS for shared storage at the TU Munich as well, while the OpenVPN Client in Tubingen is running as a VM inside XenServer itself to provide the VPN Tunnel.
The purpose of the setup is to provide an environment to demonstrate the possibility to migrate a VM between different subnets while maintaining reachability throughout the migration, which is the topic of my thesis. Even though this is not implemented yet the migration over the distance, while just using a pretty standard internet connection and a VPN Tunnel, is. I decided to create a screencast to demonstrate this, in it’s first form, which is working since yesterday.
I plan to have a demo of a working migration with constant reachability when my thesis is done.
Kind of hard to see in the current video quality, the top server is located at Tubingen in a 10.1.1.0/24 Subnet, with a TestVM running, while the other Server is located at the TU Munich with a 10.0.0.0/24 Subnet, both running XenServer 5.5. The TestVM runs a little script printing the current date every second, to demonstrate there is no real downtime during the Live Migration.