mjhjmtu

Is there a single (simple) command that will create a veth interface pair and assign each interface to a different network namespace?

For example, suppose that I have two namespaces: mynamespace-1 and mynamespace-2. Is there a single (simple) command that will connect these two namespaces via a veth pair where each endpoint of the interface is named eth0?

Currently what I would do is create the veth pair, move each interface to the corresponding namespace, and then rename the interface from within that namespace. I'd like to know if these three commands can be compressed into a single command.

For context, here is an example of how I am currently connecting a pair of namespaces and testing the connection:

# Create two network namespaces
sudo ip netns add 'mynamespace-1'
sudo ip netns add 'mynamespace-2'

# Create a veth virtual-interface pair
sudo ip link add 'myns-1-eth0' type veth peer name 'myns-2-eth0'

# Assign the interfaces to the namespaces
sudo ip link set 'myns-1-eth0' netns 'mynamespace-1'
sudo ip link set 'myns-2-eth0' netns 'mynamespace-2'

# Change the names of the interfaces (I prefer to use standard interface names)
sudo ip netns exec 'mynamespace-1' ip link set 'myns-1-eth0' name 'eth0'
sudo ip netns exec 'mynamespace-2' ip link set 'myns-2-eth0' name 'eth0'

# Assign an address to each interface
sudo ip netns exec 'mynamespace-1' ip addr add 192.168.1.1/24 dev eth0
sudo ip netns exec 'mynamespace-2' ip addr add 192.168.2.1/24 dev eth0

# Bring up the interfaces (the veth interfaces the loopback interfaces)
sudo ip netns exec 'mynamespace-1' ip link set 'lo' up
sudo ip netns exec 'mynamespace-1' ip link set 'eth0' up
sudo ip netns exec 'mynamespace-2' ip link set 'lo' up
sudo ip netns exec 'mynamespace-2' ip link set 'eth0' up

# Configure routes
sudo ip netns exec 'mynamespace-1' ip route add default via 192.168.1.1 dev eth0
sudo ip netns exec 'mynamespace-2' ip route add default via 192.168.2.1 dev eth0

# Test the connection (in both directions)
sudo ip netns exec 'mynamespace-1' ping -c 1 192.168.2.1
sudo ip netns exec 'mynamespace-2' ping -c 1 192.168.1.1

The best that I can offer is to execute the command in one namespace (using the -n shortcut), create each endpoint with the same name, and move one of them into a different namespace in that command:

ip -n mynamespace-1 link add eth0 type veth peer name eth0 netns mynamespace-2

You'll still need to do the other stuff like address assignment (the -n abbreviation may also be helpful), so you'll have to write a script, anyway.

As man ip says, the -n option is a shortcut for ip netns exec ... ip ..., so you can use this form if your ip doesn't support the -n option.