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Comment by Scaevolus | Hacker News Reader

Google Compute Engine has live migration, so host/hypervisor updates (including security updates!) can be applied without taking VMs offline. AWS doesn't support live migration. Azure has a partial solution with in-place migrations, which involves taking VMs down for ~30 seconds.

(I work on Google Container Engine.)

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Google Compute Engine has live migration, so host/hypervisor updates (including security updates!) can be applied without taking VMs offline. AWS doesn't support live migration.

I don't work for AWS, so I can only speculate about their internal technology; but they've demonstrated an ability to apply security updates without requiring guests to reboot.

I believe in certain situations they've been able to use ksplice or similar mechanisms.

Yeah, but you can do that with plain-old qemu. It's a mystery to me why more places don't do this.

Can you explain the azure solution some more please, to the best of your knowledge

This links to the announcement and has some speculation about how it's implemented. It looks like it might be basically a snapshot and a fast host reboot? https://www.petri.com/new-azure-iaas-features-announced-augu...

Probably means that upgrades are done in-place. They don't move the VM between machines, but they do something like move it from the old process to and upgraded version (or in some other way upgrade the software underneath).

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