Make your Docker containers accessible over local DNS.
What does it do?
This service iterates over Docker containers that have a macvlan network and container_name assigned to them, and exposes a hosts file that can be used with CoreDNS.
Prerequisites
Create a Docker macvlan network:
# This is just an example, adapt to your needs
$ docker network create -d macvlan --subnet=10.1.30.0/24 --gateway=10.1.30.1 -o parent=eth0.30 vlan.30
Usage
docker-compose.yaml
docker-dns-monitor:
container_name: docker-dns-monitor
image: ghcr.io/ad-on-is/docker-hosts-provider
restart: always
environment:
- DOMAIN=home.arpa # Use your preferred local DNS (homelab.lan, my.home, etc.)
volumes:
- /var/run/docker.sock:/var/run/docker.sock
- /path/to/generated/hosts:/etc/docker_hosts
coredns:
image: coredns/coredns
container_name: coredns
restart: always
ports:
- 53:53
- 53:53/udp
volumes:
- ./Corefile:/Corefile
- /path/to/generated/hosts:/etc/coredns/hosts
command: -conf /Corefile
example-container:
image: nginx
container_name: web
networks:
vlan.30:
ipv4_address: 10.1.30.20 # (optional)
networks:
vlan.30:
external: true
Corefile
To use with CoreDNS:
. {
log
errors
debug
health
ready
hosts /etc/coredns/hosts {
reload 10s
fallthrough
}
cache 30
reload
loadbalance
}
DNS/PTR Entries
To make it work, you need to tell your DNS server (router, Pi-hole, etc.) about CoreDNS and the subnet range to look for the DNS/PTR entries.
If your LAN spans from 10.1.0.0 to 10.1.255.255, and CoreDNS runs on 10.1.0.2, this is what you’d do:
dnsmasq.conf
# This is just an example, adapt to your needs
server=/1.10.in-addr.arpa/10.1.0.2
Verify It Works
Execute the following commands on a machine that is within your network:
$ ping web.home.arpa
# PING web.home.arpa (10.1.30.20) 56(84) bytes of data.
# 64 bytes from web.home.arpa (10.1.30.20): icmp_seq=1 ttl=64 time=0.182 ms
$ dig -x 10.1.30.20
# ...
# ;; ANSWER SECTION:
# 20.30.1.10.in-addr.arpa. 3600 IN PTR web.home.arpa.
# ...