Ubuntu 12.10 KVM : change Memory size of VMs on the f

KVM host

# lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 12.10 Release:        12.10 Codename:       quantal # uname -ri 3.5.0-17-generic x86_64 # kvm --version QEMU emulator version 1.2.0 (qemu-kvm-1.2.0+noroms-0ubuntu2, Debian), Copyright (c) 2003-2008 Fabrice Bellard # libvirtd --version libvirtd (libvirt) 0.9.13

VM

root@ubuntu12-04-vm1:~# lsb_release -a No LSB modules are available. Distributor ID: Ubuntu Description:    Ubuntu 12.04.1 LTS Release:        12.04 Codename:       precise root@ubuntu12-04-vm1:~# uname -ri 3.5.0-030500-generic x86_64

[ change a memory size of VM on the fly ]

on the KVM host , check the current memory size. ( 512MB )

virsh # qemu-monitor-command --hmp ubuntu12-04-vm1 'info balloon' balloon: actual=512

On the VM

root@ubuntu12-04-vm1:~# egrep -i memtotal /proc/meminfo MemTotal:         503052 kB

Change memory sitze to 256MB from 512MB.
On the KVM host

virsh # qemu-monitor-command --hmp ubuntu12-04-vm1 'balloon 256'

On the VM. Mem size has changed from 512 MB to 256MB.

root@ubuntu12-04-vm1:~# egrep -i memtotal /proc/meminfo MemTotal:         240908 kB