That's where VMware on aws comes in ;) you get vmotion, so no downtime due to planned maintenance

I was thinking of live migration performed by AWS. Are there situations where running your own VMware could help, beyond what AWS can do themselves? If there's a sudden outage, neither helps, as the instance disappears. If there's a minor issue, either should be possible.

Well, if your instance is important enough, there's vSphere Fault Tolerance [0]:

> You can use vSphere Fault Tolerance (FT) for most mission critical virtual machines. FT provides continuous availability for such a virtual machine by creating and maintaining another VM that is identical and continuously available to replace it in the event of a failover situation.

> The protected virtual machine is called the Primary VM. The duplicate virtual machine, the Secondary VM, is created and runs on another host. The primary VM is continuously replicated to the secondary VM so that the secondary VM can take over at any point, thereby providing Fault Tolerant protection.

> ...

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[0]: https://docs.vmware.com/en/VMware-vSphere/6.7/com.vmware.vsp...