readme

README.md

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+# docker-hosts-provider
+
+Make your docker containers accesible 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 hosts-file that can be used with [CoreDNS](https://github.com/coredns/coredns).
+
+## Prerquisites
+
+Create a Docker macvlan network
+
+```bash
+# 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
+
+```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 prefered local DNS (homelab.lan, my.home, etc...)
+  volumes:
+    - /var/run/docker.sock:/var/run/docker.sock
+    - /path/to/geneated/hosts:/etc/docker_hosts
+
+coredns:
+  image: coredns/coredns
+  container_name: coredns
+  restart: always
+  ports:
+    - 53:53
+    - 53:53/udp
+  volumes:
+    - ./Corefile:/Corefile
+    - /path/to/geneated/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 actually work, you need to tell your DNS-server (router, pihole, 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
+
+```bash
+# 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.
+
+```bash
+$ 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.
+# ...
+
+```