delete-orphaned-veth.sh

#!/bin/bash

veth_in_use=()
veth_all=()

for container in $(docker ps --format '{{.Names}}'); do
    pid=$(docker inspect --format '{{.State.Pid}}' $container)
    ifindex=$(nsenter -t $pid -n ip link | sed -n -e 's/.*eth0@if\([0-9]*\):.*/\1/p')
    if [ -z "$ifindex" ]; then
        echo "container:$container doesn't have veth"
    else
        veth=$(ip -o link | grep ^$ifindex: | sed -n -e 's/.*\(veth[[:alnum:]]*\).*/\1/p')
        veth_in_use+=($veth)
    fi
done

for i in $(brctl show | grep veth | awk '{print $(NF)}')
do
    veth_all+=($i)
done

exist_orphaned=false
delete_orphaned=true

for i in "${veth_all[@]}"
do
    for j in "${veth_in_use[@]}"
    do
        [[ $i == "$j" ]] && continue 2
    done
    ip link set $i down
    ip link delete $i
    if [ $? -ne 0 ]; then
        echo "deleted orphaned veth: ${i} failed"
        delete_orphaned=false
    else
        echo "deleted orphaned veth: ${i} successfully"
    fi
    exist_orphaned=true
done