Cannot allocate the VM following the constraints - one_drs

Product Support Operations
1

Hello,

I’d like to let one_drs making the initial placement of my VMs.
I then changed
ARGUMENTS = “-t 15 -p rank -o one_drs”
by
ARGUMENTS = “-t 15 -p one_drs -o one_drs”

on /etc/one/oned.conf and restarted opennebula service.

Since then I can’t deploy a VM anymore (while it’s working fine with -p rank). I get the following errors:
oneadmin@debian-opennebula-R2:/var/log/one$ cat 5971.log
Mon Sep 8 11:22:06 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:23:06 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:24:06 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:25:06 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:26:07 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:27:07 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints
Mon Sep 8 11:28:07 2025 [Z0][VMM][E]: Cannot allocate the VM following the constraints

But I don’t know where to check to understand which constrain is blocking.

Thanks in advance for your help,
Benjamin

2

Hello @Benjamin,

Apologies for the delayed reply. From what I could check, the recommendation is to check oned.log around the deployment time for messages about rejected hosts or constraints not matched.

Another workaround should be review the DRS Rules, and check if the VM resources are available for the hosts.

If you can, share the output of your one.vm.template, your current one_drs configuration / rules, and a snippet of the oned.log showing the error around the time of VM allocation. That will help the team see which constraint is failing.

Cheers,