Connect network namespaces with linux-bridge and veth's

connect-netns-w-bridge.sh

#! /bin/bash

set -ex 

function cleanup() {
    set +e
    ip netns exec blue ip link del dev veth-blue
    ip netns exec red ip link del dev veth-red
    ip netns del blue
    ip netns del red
    ip link del dev br-veth-blue
    ip link del dev br-veth-red
    ip link del dev br0
    set -e
}

function main(){
    ip netns add blue
    ip netns add red

    ip link add veth-blue type veth peer name br-veth-blue
    ip link add veth-red  type veth peer name br-veth-red

    ip link set veth-blue netns blue
    ip link set veth-red  netns red

    ip netns exec blue ip addr add 192.168.1.10/24 dev veth-blue
    ip netns exec red  ip addr add 192.168.1.20/24 dev veth-red

    ip link add name br0 type bridge
    ip link set br0 up

    ip link set br-veth-blue up
    ip link set br-veth-red  up
    ip netns exec blue ip link set veth-blue up
    ip netns exec red ip link set veth-red up
    
    ip link set br-veth-blue master br0
    ip link set br-veth-red  master br0

    bridge link show br0

    ip netns exec blue ping 192.168.1.20 -w 2 || true
    ip netns exec red  ping 192.168.1.10 -w 2|| true 

    ip addr add 192.168.1.1/24 dev br0
    ip link set up dev br0

    ip netns exec blue ping 192.168.1.20 -w 2 || true
    ip netns exec red  ping 192.168.1.10 -w 2 || true 
}

trap "cleanup" EXIT

main