VMs migrated from xcp-ng-3 to xcp-ng-3 (the same host!)

[techjeff]

Hello. I don't have a bug to report per se, but more of a curious observation. I'm looking to see if there is an obvious explanation for what I saw that I'm not familiar with. Also not sure if this belongs here or in the XO category.

I'm using XO built from sources (just updated to commit 3c047 this morning after the 5.87 Release).

I have 3 xcp-ng 8.2.1 hosts, xcp-ng-1, xcp-ng-2, xcp-ng-3 (master). To save power, I have been only using xcp-ng-1 and xcp-ng-3 while keeping xcp-ng-2 powered off. I have several VMs with host-affinity set to xcp-ng-3 because it has slower, lower TDP CPUs and I want to reserve xcp-ng-1 for vms running a game servers as it has faster CPUs.

Today I powered up xcp-ng-2 to perform a rolling pool update which went smoothly and was uneventful except that once the final host had updated, several VMs appeared to migrate from xcp-ng-3 to xcp-ng-3 (the same host, no typo) which seemed strange to me...

I checked in several places--list of running vms, the VMs themselves, list of hosts, tasks, etc.--but they all consistently showed that the VMs were being migrated from xcp-ng-3 to xpc-ng-3 and the only machine that was "busy" (yellow/amber) was xcp-ng-3 which is the pool master.

Perhaps the load balancer plugin decided that it should run after the rolling pool update to redistribute compute resources and some of the VMs it picked had host-affinity for the host they were already running on which resulted in them being migrated to the same host? This sounds silly to say haha -- I didn't think it was possible or that there would ever be a reason to migrate this way and I'm feeling a bit gaslit

All jokes aside, I'm "reporting" this behavior in case it might indicative to devs of some greater issue, but mostly I'm curious why this would happen. Has anyone seen something like this before?

Thanks in advance!

EDIT Here's a screenshot of my task history that shows what I saw:

[olivierlambert]

So you are using the load balancer plugin? It should be disable during a RPU, and re-enabled after. You should take a look at xo-server output to see what's going on

[pdonias]

@techjeff Thanks for the report, it should be fixed on master

[techjeff]

@pdonias thanks for the update! I took a look at the latest commit and apparently I was right even though it didn't feel right.

Thanks again to you all for this amazing set of FOSS tools!