AuxAddress option not working while creating network through Docker API.

Hello,

I am trying to create docker network using docker API. The main purpose is to configure Aux address so not to assign certain IP address to containers.

Expected behavior:
Docker network should be created and on inspecting should have the excluded aux address configured.

Actual behavior:
Aux address are not configured.

Steps to reproduce:
Below was the curl API call have used in creating the network.

curl --unix-socket /var/run/docker.sock -H "Content-Type: application/json" -d '{"Name":"aux-2", "Driver": "bridge", "IPAM": {"Config":[{"Subnet": "192.0.0.0/24", "Gateway": "192.0.0.1", "AuxAddress": "Exclude:192.0.0.2"}] }}' -X POST http:/v1.39/networks/create

By taking official docker API create network reference, above curl call is defined, but Aux address are not configured.

docker network inspect aux-2

[
    {
        "Name": "aux-2",
        "Id": "4dc78b44dd15778846b9b52aeea7c53c37a20a0993b6817048e2b247873147db",
        "Created": "2018-11-16T16:56:24.16356905+05:30",
        "Scope": "local",
        "Driver": "bridge",
        "EnableIPv6": false,
        "IPAM": {
            "Driver": "default",
            "Options": null,
            "Config": [
                {
                    "Subnet": "192.0.0.0/24",
                    "Gateway": "192.0.0.1"
                }
            ]
        },
        "Internal": false,
        "Attachable": false,
        "Ingress": false,
        "ConfigFrom": {
            "Network": ""
        },
        "ConfigOnly": false,
        "Containers": {
            "93103289e29143244ed362c881cdbd0da1d0c87ce2ac3d7eabc302b775835142": {
                "Name": "server1",
                "EndpointID": "f97cc787dd36ac1a9d901f7274c85d9cef7566ea5a0ffde887bbdbba65bc5f18",
                "MacAddress": "02:42:c0:00:00:02",
                "IPv4Address": "192.0.0.2/24",
                "IPv6Address": ""
            }
        },
        "Options": {},
        "Labels": {}
    }
]

How to configure Aux addresses in docker API call?

Thanks and Regards,
Mohan

Start with the documented v1.39 NetworkCreate request and the curl payload, then compare the returned network inspect output with the requested AuxAddress value. Trace how the API handles IPAM Config and define done as preserving the AuxAddress entry and excluding that address from container assignment.