# How to test Vhost-user net with OpenVSwitch/DPDK The purpose of this document is to illustrate how to test vhost-user-net in cloud-hypervisor with OVS/DPDK as the backend. ## Framework It's a simple test to validate the communication between two virtual machine, connecting them to vhost-user ports respectively provided by `OVS/DPDK`. ``` +----+----------+ +-------------+-----------+-------------+ +----------+----+ | | | | | | | | | | | |vhost-user|----------| vhost-user | ovs | vhost-user |----------|vhost-user| | | |net device| | port 1 | | port 2 | |net device| | | | | | | | | | | | | +----------+ +-------------+-----------+-------------+ +----------+ | | | | | | | |vm1 | | dpdk | | vm2 | | | | | | | +--+---------------------------------------------------------------------------------------------+--+ | | hugepages | | | +---------------------------------------------------------------------------------------------+ | | | | host | | | +---------------------------------------------------------------------------------------------------+ ``` ## Prerequisites Prior to running the test, the following steps need to be performed. - Enable hugepages - Install DPDK - Install OVS Here are some good references for detailing them. - Red Hat * https://wiki.qemu.org/Documentation/vhost-user-ovs-dpdk - Ubuntu server * https://help.ubuntu.com/lts/serverguide/DPDK.html * https://software.intel.com/en-us/articles/set-up-open-vswitch-with-dpdk-on-ubuntu-server ## Test The test runs with multiple queue (MQ) support enabled, using 2 pairs of TX/RX queues defined for both OVS and the virtual machine. Here are the details on how the test can be run. _Setup OVS_ `ovs_test.sh` is created to setup and start OVS. OVS will provide the `dpdkvhostuser` backend running in server mode. ```bash mkdir -p /var/run/openvswitch modprobe openvswitch killall ovsdb-server ovs-vswitchd rm -f /var/run/openvswitch/vhost-user* rm -f /etc/openvswitch/conf.db export DB_SOCK=/var/run/openvswitch/db.sock ovsdb-tool create /etc/openvswitch/conf.db /usr/share/openvswitch/vswitch.ovsschema ovsdb-server --remote=punix:$DB_SOCK --remote=db:Open_vSwitch,Open_vSwitch,manager_options --pidfile --detach ovs-vsctl --no-wait init ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-lcore-mask=0xf ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-socket-mem=1024 ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=true ovs-vsctl --no-wait set Open_vSwitch . other_config:pmd-cpu-mask=0xf ovs-vswitchd unix:$DB_SOCK --pidfile --detach --log-file=/var/log/openvswitch/ovs-vswitchd.log ovs-vsctl add-br ovsbr0 -- set bridge ovsbr0 datapath_type=netdev ovs-vsctl add-port ovsbr0 vhost-user1 -- set Interface vhost-user1 type=dpdkvhostuser ovs-vsctl add-port ovsbr0 vhost-user2 -- set Interface vhost-user2 type=dpdkvhostuser ovs-vsctl set Interface vhost-user1 options:n_rxq=2 ovs-vsctl set Interface vhost-user2 options:n_rxq=2 ``` _Run ovs_test.sh_ ```bash ./ovs_test.sh ``` _Launch the VMs_ VMs run in client mode. They connect to the socket created by the `dpdkvhostuser` backend. ```bash # From one terminal. We need to give the cloud-hypervisor binary the NET_ADMIN capabilities for it to set TAP interfaces up on the host. ./cloud-hypervisor \ --cpus boot=2 \ --memory size=512M,file=/dev/hugepages \ --kernel vmlinux \ --cmdline "reboot=k panic=1 nomodules i8042.noaux i8042.nomux i8042.nopnp i8042.dumbkbd root=/dev/vda3" \ --disk path=clear-kvm.img \ --net "mac=52:54:00:02:d9:01,vhost_user=true,socket=/var/run/openvswitch/vhost-user1,num_queues=4" # From another terminal. We need to give the cloud-hypervisor binary the NET_ADMIN capabilities for it to set TAP interfaces up on the host. ./cloud-hypervisor \ --cpus boot=2 \ --memory size=512M,file=/dev/hugepages \ --kernel vmlinux \ --cmdline "reboot=k panic=1 nomodules i8042.noaux i8042.nomux i8042.nopnp i8042.dumbkbd root=/dev/vda3" \ --disk path=clear-kvm.img \ --net "mac=52:54:20:11:C5:02,vhost_user=true,socket=/var/run/openvswitch/vhost-user2,num_queues=4" ``` _Setup VM1_ ```bash # From inside the guest sudo ip addr add 172.100.0.1/24 dev enp0s3 ``` _Setup VM2_ ```bash # From inside the guest sudo ip addr add 172.100.0.2/24 dev enp0s3 ``` _Ping VM1 from VM2_ ```bash # From inside the guest sudo ping 172.100.0.1 ``` _Ping VM2 from VM1_ ```bash # From inside the guest sudo ping 172.100.0.2 ``` __Result:__ At this point, VM1 and VM2 can ping each other successfully. We can now run `iperf3` test. _Run VM1 as server_ ```bash # From inside the guest iperf3 -s -p 4444 ``` _Run VM2 as client_ ```bash # From inside the guest iperf3 -c 172.100.0.1 -t 30 -p 4444 & ```