OVS – DPDK on Openstack Newton

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In this tutorial we will show detailed instructions and debugging info, in order to deploy a DPDK enabled OVS on an Openstack Newton environment, on Ubuntu 16.04.

First and foremost you must have a working Openstack Newton environment with OVS networking.

Secondly you need to have a DPDK enabled OVS, built and running on your system.

The easy way to do that is to just download and configure the official package.

Following these instructions:

https://software.intel.com/en-us/articles/using-open-vswitch-with-dpdk-on-ubuntu

sudo apt-get install openvswitch-switch-dpdk
sudo update-alternatives --set ovs-vswitchd /usr/lib/openvswitch-switch-dpdk/ovs-vswitchd-dpdk

This will install the ovs with dpdk in it. But we also need to add some parameters to the configuration files, and also enable it.

However, before that we need to build DPDK and reserve some hugepages in order to make it run successfully.

The easiest way I have found to do so is, download the DPDK source from dpdk.org, and then run the ./<DPDK-dir>/tools/dpdk-setup.sh

Then select the reserve hugepages option and enter the number. (For us it was 4096 x 2MB hugepages).

Now it is time to configure our OVS files

at the /etc/default/openvswitch-switch, an example configuration would be:

DPDK_OPTS='--dpdk -c 0x3 -n 4 --socket-mem 512 --vhost-owner libvirt-qemu:kvm --vhost-perm 0660'

SIDENOTE: The vhost-perm parameter is very important, as it may lead to a permission denied error in kvm, when binding the port to the VM

So one more thing needs to be configured at the /etc/libvirt/qemu.conf

You need to set:

user = "root"
group = "root"

Then as OVS is running exectute this command:

ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=true

And then restart the ovs service.

service openvswitch-switch restart.

Check the logs to see the successful execution

You should see something like this at the /var/log/openvswitch/ovs-vswitchd.log:

dpdk|INFO|DPDK Enabled, initializing
dpdk|INFO|No vhost-sock-dir provided - defaulting to /var/run/openvswitch
dpdk|INFO|EAL ARGS: ovs-vswitchd --socket-mem 1024,0 -c 0x00000001
dpdk|INFO|DPDK pdump packet capture enabled
ofproto_dpif|INFO|netdev@ovs-netdev: Datapath supports recirculation
ofproto_dpif|INFO|netdev@ovs-netdev: MPLS label stack length probed as 3

One cause of failure would occur if someone does not reserve sufficient hugepages, or does not fill the configuration files correctly.

From then on, the Openstack part remains to be configured

Now comes the first tricky part. Most guides state that you need to configure the tag [OVS] at the ml2_conf.ini, like this:

[OVS]
datapath_type=netdev
vhostuser_socket_dir=/var/run/openvswitch

what they fail to state is that at the Newton release you need to change the /etc/neutron/plugins/ml2/openvswitch_agent.ini , which overwrites the ml2_conf.ini .

Once OVS is correctly configured with DPDK support, vhost-user interfaces are completely transparent to the guest. However, guests must request large pages. This can be done through flavors. For example:

openstack flavor set m1.large –property hw:mem_page_size=large

At last we are ready to setup and boot a DPDK-port enabled VM.

We can boot it through an already created network, or create a new network.