Hotplug (qemu disk,nic,cpu,memory)

Proxmox support hotplugging of qemu devices

- disks (hotplug/unplug)

- nics (hotplug/unplug)

- cpu (core hotplug only)

- memory (hotplug only - not yet released)

Linux Guests notes

you need to have 2 modules loaded in your linux guest

#modprobe acpiphp
#modprobe pci_hotplug

for 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: 1

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: 1
maxcpus: 16

You will start your vm with 1 cpu|cores, and you can hotplug later up to 16 cores. Note that you can hotplug sockets with multiple cores, so don't defined socket option

memory hotplug

Need to be done