Quick setup description: TrueNAS Scale on a server in my LAN, in which I have deployed a local DNS (Pihole). This acts as a DNS for TrueNAS along with Google’s (I think I configured it manually, although my router spreads this config as part of its DHCP). Next steps are to deploy a reverse proxy.
The problem I’m facing is apps cannot reach this local DNS. At first I thought it was unreachable for them, but if I am able to curl the DNS web interface. Can anyone help me understand/fix this?
If the curl failed too, it wouldn’t surprise me. The container doesn’t have a bridge interface, and there is probably no route to the 192.168.x.x network (I guess). But since it works, I’m afraid I might be misunderstanding something.
Are you using your own compose files for your apps or the official apps?
If I go off my own setup with traefik as reverse proxy, my container needed to share a common docker network for it to work properly. All my apps I expose via traefik are joined to the common network called proxy and I use blocky as DNS server for local DNS resolution.
Afaik it’s not possible for official apps to join other networks and I have no idea how it would work with them…
I was also thinking about creating a shared network for the containers and make the DNS serve requests there, but then I thought I would run into the following problem: who is going to serve as a DHCP for the docker network, to advertise my Pihole (with its internal IP, not the 192.168.x.x) as the DNS?
Let me explain: I would have my router, in my 192.168.x.x network advertising the Pihole (192.168.1.146) as the DNS. But who would advertise Pihole’s internal interface (let’s say, 172.16.5.5) as the DNS for the docker network?
Also, I’m afraid that maybe what I create using docker won’t work in the future, since it looks like TrueNAS is migrating to Incus (apologies if what I’m saying here doesn’t make a lot of sense, I’ve been trying to catch up with this topic, which is kind of out of my confort zone)
Docker isn’t going away, incus is replacing the old vm backend while also providing the backend for lxc containers, which are a lot more like jails on truenas core/bsd. You can deploy an incus container and install any software you want via apt, like you would do in a vm, but its much more light weight
Sorry for the delayed reply, I wanted to take some time to research a little bit about what you told me and make sure I understand it correctly. And it was a pretty clarifying answer too, so thank you! ^^
I am also moving into custom apps using docker-compose files. First I want to understand why this is happening, but after that I will probably go through this path.
DNS queries from a container fail when using UDP, while TCP queries work fine. The DNS server is the Pihole service exposed through TrueNAS’s IP (192.168.1.146:53).
DNS service is listening on both TCP and UDP ports (I am able to query it from TrueNAS shell).
TrueNAS network config doesn’t look bad (although I might be missing something here)
