Docker create network should ignore existing network

Question

Currently there is no way to force it OR ignore it but you can get rid of this problem using shell -

docker network create --driver bridge my_local_network || true

This way whenever your build script executes, if there is no network it will create one else it will return true without any command failure so that rest of the build script can execute.

Building on @AndyTriggs' answer, a neat (and correct) solution would be:

docker network inspect my_local_network >/dev/null 2>&1 || \
    docker network create --driver bridge my_local_network

You can first test for the existence of the network, and create it if it doesn't exist. For example:

docker network ls|grep my_local_network > /dev/null || echo "network does not exist"

Replace the echo with your network create command:

docker network ls|grep my_local_network > /dev/null || docker network create --driver bridge my_local_network

You can do it also in this way:

NETWORK_NAME=my_local_network
if [ -z $(docker network ls --filter name=^${NETWORK_NAME}$ --format="{{ .Name }}") ] ; then 
     docker network create ${NETWORK_NAME} ; 
fi

Advantages:

1. Regexp prevents omitting network creation in case of existing network with similar name.
2. Errors in docker commands will not pass silently.

In fact it is very similar to the solution provided by @yktoo in comment under the answer of @Andy Triggs.

You can use grep simply like below, without printing out any errors:

if [[ "$(docker network ls | grep "${networkName}")" != "" ]] ; then
    docker network rm "${networkName}"
fi

docker network create --subnet=172.10.0.0/16 "${networkName}"

In this case, I assume that already created one network can have a different subnet configuration than mine.

For your case will be:

if [[ "$(docker network ls | grep "${networkName}")" == "" ]] ; then
    docker network create "${networkName}"
fi

If you can use PowerShell

$networkName = "some name here"

if (docker network ls | select-string $networkName -Quiet )
{
    Write-Host "$networkName already created"
} else {
    docker network create $networkName
}

Tried on PS core 7.0.3 - this version is available for Linux.