openstack-manuals/doc/config-reference/source/compute/resize.rst

Configure resize

Resize (or Server resize) is the ability to change the flavor of a server, thus allowing it to upscale or downscale according to user needs. For this feature to work properly, you might need to configure some underlying virt layers.

KVM

Resize on KVM is implemented currently by transferring the images between compute nodes over ssh. For KVM you need hostnames to resolve properly and passwordless ssh access between your compute hosts. Direct access from one compute host to another is needed to copy the VM file across.

Cloud end users can find out how to resize a server by reading the OpenStack End User Guide <http://docs.openstack.org/user-guide/ cli_change_the_size_of_your_server.html>.

XenServer

To get resize to work with XenServer (and XCP), you need to establish a root trust between all hypervisor nodes and provide an /image mount point to your hypervisors dom0.