Impossible to create docker network with --ipv6

[ruben-herold]

hi,

try to run the self-hosted runner on IPv6 only system. Runner runs fine on the system and connected thanks to nat64 to github.
Docker config on the host:

{
"ipv6": true,
"ip6tables": true,
"experimental": true,
"fixed-cidr-v6": "fd00::/64",
"default-address-pools": [
    { "base": "172.17.0.0/16", "size": 16 },
    { "base": "172.18.0.0/16", "size": 16 },
    { "base": "172.19.0.0/16", "size": 16 },
    { "base": "172.20.0.0/14", "size": 16 },
    { "base": "172.24.0.0/14", "size": 16 },
    { "base": "172.28.0.0/14", "size": 16 },
    { "base": "192.168.0.0/16", "size": 20 },
    { "base": "fd01::/64", "size": 112 }
  ]
}

But all container networks created via action runner are always without IPv6. See your code:

      public async Task<int> DockerNetworkCreate(IExecutionContext context, string network)
        {
#if OS_WINDOWS
            return await ExecuteDockerCommandAsync(context, "network", $"create --label {DockerInstanceLabel} {network} --driver nat", context.CancellationToken);
#else
            return await ExecuteDockerCommandAsync(context, "network", $"create --label {DockerInstanceLabel} {network}", context.CancellationToken);
#endif

There is no possible way to inject --ipv6 to it.
Docker has no config flag to enable it by default

Solution add a config option to enable ipv6 on network create.

[ruben-herold]

I build a quick and dirty work around .. not nice but working (only for documentation):

#! /bin/sh
if  [[ "${1}" == "network" ]] && [[ "${2}" == "create" ]]
  then
    /usr/bin/docker ${1} ${2} --ipv6 ${3} ${4} ${5}
  else
    /usr/bin/docker "${@}"
fi

Put this as docker in the PATH

[marko-k0]

Alternative is to trying to use host network (that is IPv6 enabled), see #3622.

[ruben-herold]

@marko-k0 I know, but this can't be the solution.