Error 13: Invalid or unsupported executable format

asai

Greetings,

After a clean shutdown yesterday, two older CentOS 5 VM that have been running fine for many years refused to come back up. I'm running XCP 7.6.

The VM CPU spikes to 100%, and I get "Error 13: Invalid or unsupported executable format" in the console.

I can't seem to restore from a recent (3 day old) snapshot either, same problem.

After doing some searching and trying launching from Grub, I'm stuck.

Can anyone shed some light on this?

Thanks for your insight.

Danp

Have you checked your logs (maybe yum.log)? Probably a recent kernel or grub update is causing the issue.

asai

@Danp ,

The crazy thing is is these are old centos 5.5 vms. They haven't had any patches for ages. Neither have the hosts been patched for quite a while...

That's what I would think too but seems unlikely in this case...

olivierlambert

I would switch them to HVM if you can, PV is dead. There's PVshim at worst.

asai

@olivierlambert , thank you for your reply.

I did switch to HVM, however that's when I get the grub bootloader screen with the Error 13: Invalid or unsupported executable format.

So, PVShim might work in this case? I will give it a shot.

olivierlambert

So if the issue is clearly inside the guest, then it's might not be related to XCP-ng

Could it be 32 bits vs 64 bits?

asai

@olivierlambert,
This is an x86_64 VM. I originally made the VM on XenServer back when it was Citrix owned. Then I actually migrated it over to KVM about 7 years ago. And then about 3 years ago, I migrated the VM back to XCP-ng using a qcow conversion routine that included running a dracut regenerate command.

dracut --regenerate-all -f && grub2-mkconfig -o /boot/grub2/grub.cfg

I wonder if I could somehow start in recovery mode and use that same command to regenerate the VM?

asai

@olivierlambert,
Is there a simple way to start the VM with PVshim? After googling around I couldn't find anything that would explain how to do this for the non-specialized person.

olivierlambert

First, I would start a live CD and chroot into it to see if you can get all the files (in case you can spot something corrupted)

asai

@olivierlambert,
Thanks for the assistance. I'm exporting the data from the VM via Live CD and will build a new VM and import applications from old VM.

asai

@olivierlambert,
I ended up copying the old application data from the crashed VM via a live CD and deployed a new VM (running on HVM.) Everything seems to be working fine now.

olivierlambert

Good news Also, now you are in HVM, which is a LOT better than PV for a lot of reasons (security, performance etc.)