docker/libnetwork default network affixed namespace

repro.sh

#!/bin/bash

# Retry a command until it succeeds or we've hit 10 attempts without it
# returning 0.
function retry_command
{
    local tries=0
    local rc=1
    local max_tries=10
    local cmd="${@}"
    while [ "${tries}" -lt "${max_tries}" ]; do
        /usr/bin/env bash <<< "${cmd}"
        rc="${?}"
        if [ "${rc}" -eq 0 ] ; then
            return 0
        else
            ((tries++))
            sleep 10 || return 2
        fi
    done
    return ${rc}
}

sudo /sbin/service docker start
retry_command "sudo docker info"
if [ "$?" -ne 0 ]; then
    echo >&2 "Unable to start docker"
    exit 1
fi

sudo docker pull registry:2

# Run a loop 100 times.
# Each iteration of the loop will start
# ten containers in parallel, then stop them in parallel.
# After the containers have stopped, check that all of
# the docker daemon's threads are in the same namespace.
# This is essentially the same repro as
# https://github.com/docker/libnetwork/issues/1113
# but with many more tries, since the bug is non-deterministic
i=1
errors=0

while [ "${i}" -le "100" ]; do
    sudo /sbin/service docker restart
    retry_command "sudo docker info"
    if [ "$?" -ne 0 ]; then
        echo >&2 "Unable to start docker"
        exit 1
    fi

    cd /proc/$(pidof docker)/task
    if [ "$?" -ne 0 ]; then
        echo >&2 "/proc/$(pidof docker)/task doesn't exist or isn't a directory."
        exit 1
    fi

    seq 10 | xargs -I{} -P10 sudo docker run -d registry:2
    if [ "$?" -ne 0 ]; then
        echo >&2 "Failed to start all containers"
        exit 1
    fi

    sudo docker ps -q | xargs sudo docker stop
    if [ "$?" -ne 0 ]; then
        echo >&2 "Failed to stop all container"
        exit 1
    fi

    namespacecount=$(sudo ls -l */ns/net \
    | awk '{print $NF}' \
    | sort -u \
    | wc -l)
    if [ "${namespacecount}" -ne "1" ]; then
        echo "Found docker daemon threads in ${namespacecount} different namespaces"
        let errors++
    fi
    let i++
done

if [ "${errors}" -ne "0" ]; then
    echo >&2 "FAIL: Daemons threads found using ${namespacecount} different namespaces"
    exit 1
fi

echo "All daemon threads used the same namespace"