I’ve tried commenting out the ports in the compose file, which should make them only available on the internal network, I thought. But when I do that, the containers can no longer connect to each other.

Did you create an explicit network for them to talk on? Otherwise the default docker network doesn’t support internal DNS queries.

https://docs.docker.com/engine/network/#container-networks

Specifically you need a network using the bridge driver: https://docs.docker.com/engine/network/drivers/bridge/

Can you share the Home Assistant automation / setup that you have for Uptime Kuma notifications? As I’m in the same boat as you. I just got a webhook setup but I’m getting flooded with notifications, especially after services update.

My hope is I just want to be notified when a particular service is down for say 5 minutes but all I care about is knowing the node name. I don’t necessarily care to get notified if the service comes back up.