Standard Network Port to NT Port Live Migration

This describes how to perform live migration from a VM with a standard network port to a VM with a Napatech virtual port with HW-offload capabilities.

Before you begin

It is possible to perform live migration from a VM with a standard network port to a VM with a Napatech virtual port. It is important to note that the migration source VM must start up initially on a Napatech port. This is because the VM must have the virtio supported features, which correspond to the Napatech hardware-offload capabilities. These virtio supported features are negotiated between the VM and the host at start-up of the VM.

Procedure

Setup OVS offload on server 1 as described in OVS-DPDK Configuration Examples without starting the VM.

Start the VM on server 1, which is the migration source:

taskset -c 8,10,12,14 /usr/libexec/qemu-kvm \
	-enable-kvm -cpu host -m 4096 -smp 4 \
	-chardev socket,id=char0,path=/usr/local/var/run/stdvio5,server=on \
	-object memory-backend-file,id=mem,size=4096M,mem-path=/mnt/huge,share=on \
	-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce=on \
	-device virtio-net-pci,packed=on,netdev=mynet1,mac=52:55:00:02:d9:03 \
	-numa node,memdev=mem -mem-prealloc \
	-net nic,macaddr=52:54:00:12:34:58 \
	-net user,hostfwd=tcp::10021-:22 \
	-nographic \
	-monitor telnet:127.0.0.1:3333,server,nowait \
	./centos7_1.img

path=/usr/local/var/run/stdvio5 is used to start the VM on a Napatech port.

Note: -monitor telnet:127.0.0.1:3333,server,nowait configures QEMU to run the VM with a control port.

Add a vhost-user-client port on server 2.

ovs-vsctl add-port br0 vhost-client-1 -- set Interface vhost-client-1 \
type=dpdkvhostuserclient options:vhost-server-path=/tmp/myVHostSock

Start the VM on server 2, which is the migration destination. For example:

taskset -c 2,4,6,8 /usr/libexec/qemu-kvm \
	-enable-kvm -cpu host -m 4G -smp 4 \
	-object memory-backend-file,id=mem,size=4G,mem-path=/mnt/huge,share=on \
	-numa node,memdev=mem -mem-prealloc \
	-chardev socket,id=char0,path=/tmp/myVHostSock,server=on \
	-netdev type=vhost-user,id=mynet1,chardev=char0,vhostforce=on \
	-device virtio-net-pci,packed=on,netdev=mynet1,mac=52:55:00:02:d9:03 \
	-net user,hostfwd=tcp::10021-:22 \
	-net nic,macaddr=52:54:00:12:34:59 \
	-incoming tcp:0:4444 \
	./centos7_1.img

path=/tmp/myVHostSock is the vhost-user-client port of the standard NIC.

This VM will, initially, not start, but waits on an incoming channel for the migration command.

Note: It is important to have the exact same VM image file on both servers.

Note: It is important to have the exact same MAC address, mac=52:55:00:02:d9:03, for the OVS virtual ports on both servers.

Use your preferred tool to validate VM connectivity:
Start live migration. On server 1, connect to QEMU using telnet:
```
telnet 127.0.0.1 3333
```
Execute the migration command in the QEMU terminal:
```
migrate -d tcp:<server 2 ip>:4444
```
Packet drop while migrating is caused by the re-programming time from stopping the first stream to redirecting the flow to the other phy. This is approx. 0.2s of traffic.
The VM is now ready to be migrated to a Napatech virtual port with HW-offload capabilities.