KVM : Live Migration

This is the example to use Live Migration feature for Virtual Machines. It requires 2 KVM host server and also a storage server like follows. Configure DNS or hosts to resolve names or IP addresses normally, first. +----------------------+ | [ NFS Servver ] | | nfs.srv.world | | | +-----------+----------+ |10.0.0.35 | +----------------------+ | +----------------------+ | [ KVM Host #1 ] |10.0.0.21 | 10.0.0.22| [ KVM Host #2 ] | | +----------+----------+ | | kvm01.srv.world | | kvm02.srv.world | +----------------------+ +----------------------+

[1]	Configure Storage server that virtual machine images are placed. For Storage server, it's OK to use NFS, iSCSI, GlusterFS and so on. It uses NFS on this example.
[2]	Configure 2 KVM host server and mount a directory provided from Storage server on the same mount point on both KVM server. It uses [/var/kvm/images] for mount point on this example.
[3]	Create and Start a Virtual Machine on a KVM Host and run Live Migration like follows. For connection between KVM Hosts, they connects to others with SSH, so it had better to set SSH key-pair with root account before running live migration.

# edit the setting of a VM you'd like to run live migration root@kvm01:~#  virsh edit debian13 <disk type='file' device='disk'> # add : change cache mode to [none] <driver name='qemu' type='qcow2' discard='unmap' cache='none'/> <source file='/var/kvm/images/debian13.img'/> root@kvm01:~#  virsh start debian13 root@kvm01:~#  virsh list Id Name State -------------------------- 1 debian13 running root@kvm01:~#  virsh migrate --live debian13 qemu+ssh://10.0.0.22/system root@kvm01:~#  virsh list Id Name State -------------------------- # VM migrated ### on another KVM Host ### root@kvm02:~#  virsh list Id Name State -------------------------- 1 debian13 running # back to the KVM Host again like follows root@kvm02:~#  virsh migrate --live debian13 qemu+ssh://10.0.0.21/system root@kvm02:~#  virsh list Id Name State --------------------------