This is used to configure and query Open vSwitch. This tool can be very useful when troubleshooting Neutron networks that leverage Open vSwith. For example, to see the contents of the configuration database, we can use the ovs-vsctl show command. Take the following example for instance:

There are a few things worth pointing out in the preceding output. You'll notice that there are two bridges, one named br-int and another named br-tun. On br-int, there are multiple ports. There is one port named tapa4391bff-da. This is the tap interface coming from our instance. You will also notice a port with a name that begins with qvo…; this is one end of a virtual Ethernet (veth) pair connected to the OVS bridge. You want to make sure that these two ports are present:

iproute2

The IPRoute2 utility is a new collection to the tools that control TCP/IP traffic and networking in Linux. The iproute2 tools are designed to replace many of the legacy tools including ifconfig and route.

There are several useful commands included in this utility. For example, the IP link command will list out the networking devices on this host.

In the preceding output, we see br-int and br-tun again. We also see the tap device. We also see a device that starts with qvo and another that starts with qvb. The letter q here refers to Quantum, which was the original name of the OpenStack Networking project before it was changed to Neutron. The letter v indicates that this device is one side of a veth pair. The letter b indicates the side of the veth pair that's plugged into the Linux bridge, and the letter o indicates the side of the veth pair that's plugged into the OVS switch.

The iproute2 has several other useful troubleshooting utilities, including ip route show, ip netns, and ip neigh.