Comment by 63stack
1 day ago
How do you handle updating the machine that Incus itself runs on? I imagine you have to be super careful not to introduce any breakage, because then all the VMs/containers go down.
What about kernel updates that require reboots? I have heard of ksplice/kexec, but I have never seen them used anywhere.
I'm not quite sure what's your question here? Very much similar to any other system which needs to reboot and you getting ready to these reboots in advance.
To some extent, of course things like vSphere/Virtuozzo and even LXD/Incus, and even simple Qemu/Virsh systems can do live migration of VMs, so you may care less on preparing things inside VMs to be fault taulerant, but to some extent.
I.e. if your team do run PostgreSQL, your run it in cluster with Patroni and VIPs and all that lovely industry standard magic and tell dev teams to use that VIP as entry point (in reality things bit more complicated with Haproxy/Pgbouncer on top, but enough to express the idea).
As with any such system, you need a spare box. Upgrade the spare, move the clients to it, upgrade the original.
But then the clients have downtime while they’re being moved.
I don't know about Incus, but on ProxMox the downtime when moving a VM is around 200 ms.
Isn't that the exact problem that k8s workloads solve by scaling onto new nodes first etc? No downtime required.
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