Avoid Reuse of VMID

[Nemesiz]

it is the relict of openvz

 

[Johannes S]

That's an interesting detail, can you explain? UUID wasn't possible with OpenVZ? Somehow funny, that an obsolete container technology (and system containers are not that great of an alternative to real vms anyhow) would lead to such longstanding issues

 

[Nemesiz]

Proxmox started as a virtualization platform based on QEMU and OpenVZ. In the OpenVZ system, virtual machine (VM) ID numbers are configured to start at 100. Have you ever wondered why, when creating a VM on a new system, the option to start with ID number 1 is not offered?

 

[proxuser77]

Interesting. I did a little Googling, and it actually seems to be a relic from OpenVZ: https://wiki.openvz.org/User_Guide/Operations_on_Containers#Choosing_Container_ID

However, I also found the following: it seems that even OpenVZ moved away from VEIDs to UUIDs more than ten years ago: https://openvz.livejournal.com/

This OpenVZ 7.0 release provides the following major improvements:

• RHEL7 (3.10+) kernel.
• KVM/QEMU hypervisor.
• Guest tools for virtual machines that currently allow the following: to execute commands in VMs from the host, to set user passwords, to set and obtain network settings, to change SIDs, to enter VMs.
• Unified management of containers and KVM virtual machines with the prlctl tool and SDK. You get a single universal toolset for all your CT/VM management needs.
• UUIDs are used to identify both virtual machines and containers. With containers, prlctl treats the former VEID parameter as name.

 

[Johannes S]

Thanks for your insights. Since ProxmxoVE changed to lxc with PVE 4.0 ( see https://pve.proxmox.com/wiki/Convert_OpenVZ_to_LXC https://pve.proxmox.com/wiki/Roadmap ), which was released in 2015, so more than ten years ago

So I guess that PVE actually never included OpenVZ with UUID support.

 

[proxuser77]

Yeah I guess so.

By the way, I totally see how this could cause problems in enterprise environments, especially when it comes to backups that are retained for a long time and end up having the same VMID as a newer VM that may serve a completely different purpose. On the other hand, if you restore an ancient backup (you probably wouldn’t just restore it over the existing VM anyway, but rather run it in parallel first, and then you’d have to assign a different VMID anyway)

But either way, for me as a home user, the VMIDs are actually still handy because I assign them to the IP address that a VM has:

VLAN 10 192.168.10.10, 192.168.10.11, etc., have VMIDs 1010, 1011, etc.
VLAN 20 192.168.20.10, 192.168.20.11, etc. have VMIDs 2010, 2011, etc.

You get the idea. ;-)