Getting started with OpenStack's provider networks

Posted by Maxime on December 17, 2016 in openstack

Provider networks might not seem like much at first glance but they are mighty powerful - they allow you to connect any network (L2 or L3) to your cloud. They are useful if your OpenStack workloads need private access to a legacy system on a specific VLAN. Common usage examples are physical appliances, storage systems, enterprise databases etc. In this post I will show you how to setup a provider network in an OpenStack cloud.


To manage provider networks you need admin permissions/role on an OpenStack cloud deployed with Neutron networking as well as VLAN-aware network gear.

How to

The cloud administrator (you need the admin role for this bit) can create a provider network and specify the VLAN ID with the following command:

neutron net-create vlan-$VLAN_ID --provider:physical_network physnet2 \
  --provider:network_type vlan \
  --provider:segmentation_id $VLAN_ID

Now we have a Neutron network for the desired VLAN ID (1234 in the example) that we can use as usual:

  • Configure subnets
  • Connect Virtual Machines
  • Attach Neutron routers

provider network

Under the hood

In the neutron net-create command the value of the --provider:physical_network parameter depends on the network topology and the Neutron ML2 plugin configuration.

In this example we trunk all VLANs on eth0 which is bridged on br-prv, then we configure the Neutron ML2 plugin to associate a label (physnet2) to the br-prv bridge interface.

# from /etc/neutron/plugins/ml2/ml2_conf.ini

For more information, the official documentation covers in details provider networks for Linux Bridges and for OVS.