I still get a little downtime during deploys, presumably due to the same slow propagation issue.
I’ve tried using 2 VMs, and also using a --canary deploy, but still happens.
This suggests using 3 VMs may help Rolling deployments sequence - #12 by amithm7 but since they are generally idle (I’d like a more serverless-style) I’d rather not add VMs just for the occasional deploy.
Beyond this (but related) what would be neat would be on-deploy to have a new set of VMs started, ready to go, and then manually/auto switch all (or a percentage) of traffic dynamically to the new environment. That would also help with rollbacks, as if there was any problem you could switch traffic back to the old one. It would depend on how quickly your load balancer updates globally to point at the new/old set, but assuming it was near-instant, that would also avoid downtime during a deploy.