Multicast networking?

[pgcudahy]

Hello, just started using colima which has been a really nice experience but have a question. Home-assistant is a home automation service that relies on multicast to auto-discover network services. They recommend using the network_mode: "host" option in docker to achieve this but that's not possible on VM based docker for mac. Is there any way to get around this?

[abiosoft]

Technically, you can set the network mode to host but it is only host to the VM, not the macOS host.

[abiosoft]

socket_vmnet actually supports both bridge and host networks as well.
However, I did not explore those as they are not the use cases for the average Colima user.

Sounds like you need bridge mode, which should make the VM visible to other computers on your network.

[pgcudahy]

Updated 2022-11-06
Now with this integrated in the github version it's even easier

brew install --HEAD colima
brew install docker docker-compose
mkdir -p ~/.docker/cli-plugins
ln -sfn $(brew --prefix)/opt/docker-compose/bin/docker-compose ~/.docker/cli-plugins/docker-compose
colima start --network-address
docker-compose -f docker-compose.yml up -d

With the standard docker-compose settings from home-assistant

I tested pinging my mdns printer from both colima ssh and docker exec -it homeassistant /bin/bash and it works in both!

[SteveMarshall]

If I'm reading this right, this means your VM/containers can see mdns devices elsewhere on the network, but what about the containers being addressable from other devices on the network?

I've a couple of things I run that need to be exposed as separate devices on the network, preferably with their own IPs and so forth. Is that what you've got here, @pgcudahy, or does your home-assistant present itself as being a service on your Mac?

[abiosoft]

Colima uses shared network and therefore the IP address is not reachable by other devices on the network.

[eelcocramer]

Updated 2022-11-06 Now with this integrated in the github version it's even easier

brew install --HEAD colima
brew install docker docker-compose
mkdir -p ~/.docker/cli-plugins
ln -sfn $(brew --prefix)/opt/docker-compose/bin/docker-compose ~/.docker/cli-plugins/docker-compose
colima start --network-address
docker-compose -f docker-compose.yml up -d

With the standard docker-compose settings from home-assistant

I tested pinging my mdns printer from both colima ssh and docker exec -it homeassistant /bin/bash and it works in both!

Your update suggests that multicast traffic from the network should be received by the colima VM guest when using the --network-address switch. When I try this I do get prompted for a password when colima starts and colima ls output displays an IP address but I'm not able to resolve bonjour services from within a docker container that uses host networking. Should this work out-of-the-box or does this require a different network driver?