VM UUID via dmidecode does not match VM ID in xen-orchestra

deefdragon

This is related to a bug I filed on the XO-CCM (which is why I put it here). I have a series of Kubernetes worker node VM's created by loading the a base k8s node from a template. It appears that in this process, the UUID returned from dmidecode has been changed and does not reflect the UUID in XO.

I was wondering if there was a way to get the UUID to match up again so that I can get the CCM to start functioning.

olivierlambert

It's likely because the VM UUID from a XAPI perspective is different (generated by XAPI) and you can fetch it by reading the appropriate xenstor entry.

deefdragon

@olivierlambert Ah. Ok. It looks like I can update the system uuid via

sudo dmidecode -s system-uuid -s <new_uuid>

found from here, but if you happen to know if that should work, Id love a confirmation before I go and make a mess of a worker node.

deefdragon

OK. back where I started. that was a garbage AI-written "help" article that just spewed out garbage commands as if they actually worked. Still looking for a way to resetset the dmi UUID

olivierlambert

Can you use another way than dmidecode to fetch the UUID? Because it's not the right way to get VM UUID (instead you should use xenstore read with the UUID key

deefdragon

@olivierlambert Unfortunatly, the UUID is getting pulled by kubernetes itself for XO-CCM, so I have no control over that that Im aware.

olivierlambert

Can you open an issue on the Github repo for the CCM?

deefdragon

@olivierlambert I already have an issue liked in my original post. do you want me to make a new issue about how the vm Id is retrieved? or just comment on the issue I already have?

olivierlambert

No, it's fine, as long the issue contains all the relevant details it's fine

Cyrille

Hi,
Do you know what causes the system UUID to change and not match the VM UUID?

In the tests I have run (with Debian and Microk8s), it never changed.

deefdragon

@Cyrille Genuinly no idea unfortunately. The only thing I can think that I've done is that the VMs are being loaded in from a template.

I had to deploy new VMs through my terraform recently, and I AM still seeing an incorrect system UUID on those, so I can only guess its somehow the template?

I am also seeing the serial number from DMIDECODE match the VM ID in xen orchestra as well still.

Cyrille

@deefdragon can you check if /sys/hypervisor/uuid matches your VMs UUID?

deefdragon

@Cyrille I am seeing /sys/hypervisor/uuid matching dmidecode's Serial Number matching VM ID in xen orchestra.

dmidecode's UUID however is different from those three.