Primary on Docker / Secondary on Raspberry Pi

[parsoli]

Hey All,

Super happy clustering is available. When I try to create a new cluster from the primary in Docker running on Proxmox, it's only allowing the internal docker IP address to be selected as shown below, not the IP address the container is using which is on a 192.x network. The secondary DNS host has no idea how to route to that IP as it too sits on a 192.x network. Is there some docker value that needs to be changed?

[ShreyasZare]

Thanks for asking. When using docker, you need to run the container in host networking mode and have static IP on the host system for this to work.

[parsoli]

Thanks. I run Technitium on an Ubuntu Server OS that is virtualized on Proxmox. When I try to add the network mode to the docker yaml file, it completely takes the docker container offline. Eventhough the Ubuntu Server OS has a static IP address which answers all calls on port 53 @ 0.0.0.0

⠧ Container dns-server Starting 0.7s
Error response from daemon: failed to set up container networking: driver failed programming external connectivity on endpoint dns-server (da3faabc0742a76bea058b614b26f444c47a7d09ab63efe2173d37526dabb3e7): failed to bind host port for 0.0.0.0:53:172.18.0.2:53/tcp: address already in use

[ShreyasZare]

The error message indicates that port 53 on the host system is already in use, most probably due to systemd-resolved running. So you need to stop any existing DNS stub resolver like systemd-resolved before running the container in host mode.