ldddns.arnested.dk

README

Local Docker Development DNS

A systemd service that will monitor your Docker host and provide DNS names for containers based of the container name.

If a VIRTUAL_HOST environment variable is present a hostname based on that will also be set.

The service broadcasts the domain names using multicast DNS (a.k.a. mDNS, zeroconf, bounjour, avahi).

A limitation of this is that domains name can only be on the .local TLD and only have one level below the TLD. A benefit is that you don't have to change your DNS server or configure stuff in /etc/resolv or similar.

The service will rewrite hostnames to match this. I.e. my.fancy.site will be rewritten to my-fancy.local.

If the containers also have exposed ports (and the ports can be looked up in /etc/services) the service will also broadcast the service/domain for service discovery (i.e. _https._tcp. for https://my-fancy.local). It will broadcast the domain based on VIRTUAL_HOST if set and otherwise the one based on the container name.

Install

For Pop!_OS, Ubuntu, Debian and the like, download the .deb package file from the latest release and open it or run:

sudo dpkg -i ldddns_0.0.57_linux_amd64.deb

Or just run the following command which will download and install the latest package for you:

curl -fsSL https://ldddns.arnested.dk/install | bash

For other distributions download the binary from the latest release and create a systemd service unit file yourself based on ldddns.service.

Updates

When you install the package it will add an APT source list so you will receive future updates to ldddns along with your other system updates.

Keeping an eye on things

You can get the status of the service by running:

sudo systemctl status ldddns.service
● ldddns.service - Local Docker Development DNS
     Loaded: loaded (/lib/systemd/system/ldddns.service; enabled; vendor preset: enabled)
     Active: active (running) since Fri 2021-01-08 09:29:46 CET; 44min ago
   Main PID: 87715 (ldddns)
      Tasks: 8 (limit: 47858)
     Memory: 5.2M
     CGroup: /system.slice/ldddns.service
             └─87715 /usr/libexec/ldddns

jan 08 09:29:46 pop-os systemd[1]: Starting Local Docker Development DNS...
jan 08 09:29:46 pop-os ldddns[87715]: Starting ldddns 0.0.57...
jan 08 09:29:46 pop-os systemd[1]: Started Local Docker Development DNS.
jan 08 10:13:52 pop-os ldddns[87715]: added address for "my-fancy.local" pointing to "172.19.0.3"
jan 08 10:13:52 pop-os ldddns[87715]: added service "_http._tcp" pointing to "my-fancy.local"

Or follow the log with:

sudo journalctl --follow --unit ldddns.service

Bugs, thoughts, and comments

Bugs, thoughts, and comments are welcome.

You can use the GitHub Issues and/or GitHub Discussions.