Using Docker on Mac Mini

[daedlo]

After many years of using QNAP to run two instances of MinimServer using Containers in order to allow searching Classical and Popular music libraries without much fuss I have moved on to a Mac mini(M4). I was hoping to have the same arrangement as before. However, even though Docker is now available on Mac systems I can't find an image to use. Does anybody know if this is possible at the moment or will I have to either manually switch profiles on the web page or use Folder view in the Linn app? The last option would however, not allow for different grouping necessary for the different types of music.
Any suggestions appreciated

[simoncn]

You should be able to use the arm64 Docker image, as the M4 is an arm64 processor.

[daedlo]

Apologies. I didn’t see the arm64 image down the list. I pulled the image filled in the options page and the container starts. However, minimwatch doesn’t see it. I can’t find any info on configuring docker on a Mac specifically. I’m using Docker desktop as I don’t know Linux so it needs to be simple for me. Cheers

[simoncn]

This is normally caused by having the Docker network option set to bridge instead of host. I have tried changing this using Docker Desktop (a truly awful piece of software) but this didn't fix the problem for some reason. I will try again on a different version of macOS. Which macOS version are you running?

[daedlo]

I suspected it had something to do with the network setting but could not see an option to change this. I am running Tahoe 26.0.1

[simoncn]

Select Settings, then select Resources, then select Network, then select Enable host networking, then click Apply & restart.

You will see a prompt asking if you want to allow Docker to find devices on local networks. Select Allow.

Under Images, search for 'minimworld'. Select 2-2-arm64 and click Pull.

At this point, host networking is enabled but there is no way that I could find to use Docker desktop to create a container that uses host networking. If you run the image suing Docker desktop, it will use bridge networking. The only way I could find to run the image with host networking was to create a container using this command from a Terminal window:

docker create -v ~/Music:/Music:ro --network host --name MinimTest minimworld/minimserver:2.2-arm64

After creating the container, I clicked the Run button in Docker desktop. Selecting the Network tab in Inspect shows that host networking is enabled but MInimServer is not visible on the local network.

This docker create command works on Linux systems and I am not sure why it doesn't work on macOS.

[simoncn]

I found this explanation in the Docker help pages:

Limitations

Processes inside the container cannot bind to the IP addresses of the host because the container has no direct access to the interfaces of the host.

The host network feature of Docker Desktop works on layer 4. This means that unlike with Docker on Linux, network protocols that operate below TCP or UDP are not supported.

MinimServer (and all UPnP servers) uses SSDP and IGMP discovery, as required by the UPnP protocol. From the above, it appears that these lower-level protocols are not supported by Docker on macOS.

[daedlo]

Thanks for that information. Given that, is there an alternative to Docker which will work or, if not, would you be able to give some ready made terminal commands as above? I did manage to follow your instructions and found my next issue would be specifying ports 9792/3 as 9790/1 were already in use by my original running MinimServer.

[simoncn]

This limitation of Docker on macOS cannot be overcome by using terminal commands.

The simplest and best way to do what you want is to run two instances of MinimServer under two different user accounts. Both instances can run at the same time.

Instance 1 should use ports 9790 and 9791. Instance 2 should use ports 9792 and 9793. You should change the default displayName settings so that your control point can distinguish between these instances. No terminal commands are needed.

[daedlo]

I have managed to get two instances of MinimServer up and running and recognised by the Linn app. We shall see how it all goes over the next few days. Thanks for the help.