In this write-up I am going to discuss virtual Machine live migration from one hypervisor to another hypervisor. For this scenario I am using KVM hypervisor. Vmotion is much discussed feature available in Vmware. Vmotion migrate live virtual machine from one host to host. Vmotion can only be used for Vmware ESX/ESXi hypervisor. Let us discuss how live migration can be performed in KVM.
Remember that guests (VM) need to fulfill following conditions to migrate actively (live migration)
— Virtual Machine must be installed on shared disk (iscsi LUN, Fiber Channel Based LUN, FCoE,NFS,GFS2 etc).
— Shared storage must be accessible from both the source and destination host.
— Both the hosts must have the appropriate tcp ports open.
— Ensure that source and destination host have same version of Operating System.
— Ensure that hostname getting resolved to IP address via DNS or /etc/hosts.
In my example, I am using CentOS 6.4 with virtualization packages installed on both the host1 and host2. I also ensured that libvirtd daemon is running on both the hosts.
I also made entries in /etc/hosts to resolve hosts via name. One fact I learned in live migration process that hostname must be resolved to IP as you can’t migrate by mentioning IP of destination server.
I issued following command Migrate guest VM from host1.linuxmantra.com to host2.linuxmantra.com
host1# virsh migrate -–live qemu+ssh://host2.linuxmantra.local/system