Hotplug (qemu disk,nic,cpu,memory)

Proxmox support hotplugging of qemu devices

- disks (hotplug/unplug)

- nics (hotplug/unplug)

- cpu (hotplug only - proxmox 3.4)

- memory (hotplug only - proxmox 3.4)

Linux Guests notes

kernel modules needed

you need to have 2 modules loaded in your linux guest

#modprobe acpiphp
#modprobe pci_hotplug

cpu && memory hotplug

you need a recent kernel > 3.10

and a udev rules, to auto enable cpus or memory hotplugged

you can add a file:

/lib/udev/rules.d/80-hotplug-cpu-mem.rules

SUBSYSTEM=="cpu", ACTION=="add", TEST=="online", ATTR{online}=="0", ATTR{online}="1"
SUBSYSTEM=="memory", ACTION=="add", TEST=="state", ATTR{state}=="offline", ATTR{state}="online"

Windows Guests notes

- Disk and nic hotplug is working out of the box for all windows versions >2003 - cpu && memory hotplug is working on > 2008 enterprise/datacenter, 2012 > standard

Disk && Nic hotplug/unplug

edit your vm configuration file

/etc/pve/qemuserver/<VMID>.conf

and add

hotplug: network,disk,....

Note: Since proxmox 3.3, hotplug option is available in GUI.

Then add/remove your disk or nics as usual.

For disk unplug, verify that your disk is not mounted in your linux guest or disabled in windows disk management.

CPU hotplug

/etc/pve/qemuserver/<VMID>.conf

and add

cores: 2
sockets: 2
vcpus: 1
hotplug: cpu,...

You will start your vm with 1 cpu|cores, and you can hotplug later up to 4 cores. maxcpus = sockets * cores.

To hotplug a new vcpu (GUI not yet available in proxmox 3.4).

1. qm set VMID -vcpus 3

This will hotplug 2 new vcpus, for a total of 3vcpus.

Note : windows cpu hotplug is currently broken (proxmox 4.1 - qemu 2.5) because of hyper_v features . It will be fixed in qemu 2.6.

Memory hotplug

Memory hotplug is available in proxmox 3.4.

You need to enable numa and hotplug to get it working

numa: 1
hotplug: memory,...

Then you can use the memory GUI as usual.