Considering VMware’s enrapturement with vMotion the following news (reported by Salman Naqvi in a comment to my blog post) was clearly inevitable:
I was surprised to learn that LIVE vMotion is supported between on-premise and Vmware on AWS Cloud
What’s more interesting is how did they manage to do it?
A few basics first:
- VMware-on-AWS has little to do with AWS or public cloud. It’s a vSphere/NSX-T/VSAN cluster managed by VMware and running on AWS bare-metal servers. The only difference between VMware-on-AWS and a vSphere cluster running in any collocation facility is that they had to cope with the fact that AWS doesn’t care about layer-2 tricks.
- VMware-on-AWS runs NSX-T, so the question really becomes “how do you do a vMotion between two NSX-T instances or between a traditional vSphere cluster and an NSX-T instance?”
Since VMware introduced cross-vCenter vMotion, it’s easy to migrate a running virtual machine across multiple vCenter deployments… all you need is a matching port group name on both ends, and end-to-end layer-2 connectivity if you expect the virtual machine to keep communicating with its environment.
The “magic” of live vMotion to VMware-on-AWS thus boils down to “how do I get layer-2 connectivity into AWS?”. Well, you don’t - AWS is not stupid enough to allow you to bring your flooding challenges into their environment… but there’s always the duct-tape-of-networking.
NSX-T includes L2VPN - bridging across an IPsec-protected GRE tunnel. Hooray, problem solved. You might experience MTU issues I was told (and that’s probably why they want you to have a DirectConnect link into AWS), but who cares about such minor inconveniences when you can do what everyone always wanted: move a running server into AWS.
You probably know my opinion on the feasibility of long-distance vMotion, long-distance bridging and L2 DCI, and the latest VMware’s trick didn’t change it a bit. If anything, the L2 DCI features they’re offering in NSX-T release 2.5 are worse than what Cisco had in OTV a decade ago
Long story short: the only advice I can give you regarding this marketing gimmick is what James Mickens told people enchanted with the promise of ML/AL:
- In three words: Think before deploying.
- In two words: Think first.
- In one word: Don’t.
On the other hand, if you want to know how stuff works behind the scenes check out: