I am using kvm and libvirt on my Dell server. Now i am trying to migrate one virtual machine from a physical server to another. However, I failed everytime.

In virsh on physicalServer1, I typed:

```
virsh # migrate virtualmachine1 qemu+ssh://username@physicalServer2/system
error: operation failed: migration to 'tcp:physicalServer2:49163' failed: migration failed

```

Then I searched [FAQ part on libvirt.org](http://wiki.libvirt.org/page/FAQ). It says:

```
error: operation failed: migration to '...' failed: migration failed

This is an error often encountered when trying to migrate with QEMU/KVM. This typically happens with plain migration, when the source VM cannot connect to the destination host. You will want to make sure your hosts are properly configured for migration (see the migration section of this FAQ)

```

I managed to `ssh physicalServer2` from a shell on virtualmachine1 so the above red part did not explain my failure.

I also open ports on physicalServer2, `iptables -L` shows following information:

```
Chain INPUT (policy ACCEPT)
target prot opt source destination
ACCEPT udp -- anywhere anywhere udp dpt:domain
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT udp -- anywhere anywhere udp dpt:bootps
ACCEPT tcp -- anywhere anywhere tcp dpt:bootps
ACCEPT udp -- anywhere anywhere udp dpt:domain
ACCEPT tcp -- anywhere anywhere tcp dpt:domain
ACCEPT udp -- anywhere anywhere udp dpt:bootps
ACCEPT tcp -- anywhere anywhere tcp dpt:bootps
ACCEPT tcp -- anywhere anywhere state NEW tcp dpts:49152:49215

Chain FORWARD (policy ACCEPT)
target prot opt source destination
ACCEPT all -- anywhere 192.168.122.0/24 state RELATED,ESTABLISHED
ACCEPT all -- 192.168.122.0/24 anywhere
ACCEPT all -- anywhere anywhere
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
ACCEPT all -- anywhere 192.168.122.0/24 state RELATED,ESTABLISHED
ACCEPT all -- 192.168.122.0/24 anywhere
ACCEPT all -- anywhere anywhere
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable
REJECT all -- anywhere anywhere reject-with icmp-port-unreachable

Chain OUTPUT (policy ACCEPT)
target prot opt source destination

```

The /var/log/libvirt/qemu/virtualmachine1.log on physicalServer2:

```
2011-05-06 13:37:30.708: starting up
LC_ALL=C PATH=/usr/local/sbin:/usr/local/bin:/usr/bin:/usr/sbin:/sbin:/bin QEMU_AUDIO_DRV=none /usr/bin/kvm -S -M pc-0.14 -enable-kvm -m 2048 -smp 1,sockets=1,cores=1,threads=1 -name openjudge-test -uuid a8c704bc-a4f9-90db-3e57-40e60b00aac1 -nodefconfig -nodefaults -chardev socket,id=charmonitor,path=/var/lib/libvirt/qemu/virtualmachine1.monitor,server,nowait -mon chardev=charmonitor,id=monitor,mode=readline -rtc base=utc -boot c -drive file=/media/nfs/virtualmachine1.img,if=none,id=drive-ide0-0-0,format=raw -device ide-drive,bus=ide.0,unit=0,drive=drive-ide0-0-0,id=ide0-0-0 -drive if=none,media=cdrom,id=drive-ide0-1-0,readonly=on,format=raw -device ide-drive,bus=ide.1,unit=0,drive=drive-ide0-1-0,id=ide0-1-0 -netdev tap,fd=20,id=hostnet0 -device rtl8139,netdev=hostnet0,id=net0,mac=00:16:36:8a:22 :a0,bus=pci.0,addr=0x3 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -usb -vnc 127.0.0.1:2 -vga cirrus -incoming tcp:0.0.0.0:49163 -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x4
char device redirected to /dev/pts/0
2011-05-06 13:37:30.915: shutting down

```

The /var/log/libvirt/qemu/virtualmachine1.log on physicalServer1 is empty.

Both physical servers are using Ubuntu 11.04. The libvirt and kvm used are installed by apt-get. The libvirt version is 0.8.8.