Installation guide

Live KVM migration with virsh
141
Locations must be the same on source and destination
Whichever directory is chosen for the guests must exactly the same on host and guest. This
applies to all types of shared storage. The directory must be the same or the migration will
fail.
18.3. Live KVM migration with virsh
A guest can be migrated to another host with the virsh command. The migrate command accepts
parameters in the following format:
# virsh migrate --live GuestName DestinationURL
The GuestName parameter represents the name of the guest which you want to migrate.
The DestinationURL parameter is the URL or hostname of the destination system. The destination
system must run the same version of Red Hat Enterprise Linux, be using the same hypervisor and
have libvirt running.
Once the command is entered you will be prompted for the root password of the destination system.
Example: live migration with virsh
This example migrates from test1.example.com to test2.example.com. Change the host
names for your environment. This example migrates a virtual machine named RHEL4test.
This example assumes you have fully configured shared storage and meet all the prerequisites (listed
here: Migration requirements).
1. Verify the guest is running
From the source system, test1.example.com, verify RHEL4test is running:
[root@test1 ~]# virsh list
Id Name State
----------------------------------
10 RHEL4 running
2. Migrate the guest
Execute the following command to live migrate the guest to the destination,
test2.example.com. Append /system to the end of the destination URL to tell libvirt that you
need full access.
# virsh migrate --live RHEL4test qemu+ssh://test2.example.com/system
Once the command is entered you will be prompted for the root password of the destination
system.
3. Wait
The migration may take some time depending on load and the size of the guest. virsh only
reports errors. The guest continues to run on the source host until fully migrated.