I used to do something like this but with ZFS on an OpenSolaris / Illumos storage server, exporting copy-on-write clones of snapshots of iSCSI volumes to boot Xen VMs on neighbouring blades, with tagged VLANs from each host because there were multiple guests to launch with varying roles in the application cluster. We made the VLAN number match 12 bits of the IP addresses and numbered the clones similarly. It merely remained to create new snapshots every release and any dev could launch an bugfix/test/showcase/etc environment for that version, and connect to it via a VPN. I was always worried about scale if we hired more than 4096 developers but fortunately the company was acquired and its product discontinued before that happened.
That was in 2007 so the control plane (scheduler and automation) were built from scratch and we had very few reference points for the overall design. If I was building that today I’d probably still use ZFS clones but at filesystem level instead of block devices, and serve jails over NFS if I can get away with it, the iSCSI part was always a little janky.
That was in 2007 so the control plane (scheduler and automation) were built from scratch and we had very few reference points for the overall design. If I was building that today I’d probably still use ZFS clones but at filesystem level instead of block devices, and serve jails over NFS if I can get away with it, the iSCSI part was always a little janky.