[from the original at: http://www.skjegstad.com/blog/2015/03/25/mirageos-vm-per-url-experiment]
I recently wrote a DNS server that can boot unikernels on demand called Jitsu. The following diagram shows a simplified version of how Jitsu works. The client sends a DNS query to a DNS server (Jitsu). The DNS server starts a unikernel and sends a DNS response back to the client while the unikernel is booting. When the client receives the DNS response it opens a TCP connection to the unikernel, which now has completed booting and is ready to respond to the TCP connection.
The unikernels are built using MirageOS, a library operating system that allows applications to be compiled directly to small Xen VMs. These unikernels only include the operating system components the application needs - nothing else is added. This results in very small VMs with low resource requirements that boot quickly.
Now, what if I wanted to use Jitsu to boot my unikernel website when someone accesses it?