I have the docker command installed on the windows box, but it occurred to me I should be able to run the command using the Ubuntu box as the host.
After a bit of digging I find :
>docker -H 192.168.2.1:2357 xxx
no luck.. fails to connect...
On Ubuntu I run
> netstat | grep docker -i
and find the 2357 port is not open... so back to google.
Turns out you need to tell dockerd to open that socket.
You can do that from the commandline when running dockerd (with the -H flag)
>dockerd -H tpc://
I have no idea where the command line is being run from, so I keep digging.
Turns out you can also configure this in a config file... daemon.json
I don't need encryption as it's all on my local network.
I add in some hosts...
> sudo systemctl daemon-reload
> sudo systemctl restart docker
BIND DOCKER TO ANOTHER HOST/PORT OR A UNIX SOCKET"
Turns out the commandline is also adding hosts... so you can't do both.
I decide to add mine to the command line too and remove it from the json.
> sudo vi /lib/systemd/system/docker.service
ExecStart=/usr/bin/dockerd -H fd:// -H tcp://0.0.0.0:2375 -H tcp://10.10.253.140:2377
the 0.0.0.0 didn't help...
so I added my actual IP address...
and that works. This isn't ideal for a few reasons. My IP address being dynamic being one.
This all took a couple of hours I won't get back, so I thought I would share.