fix: persist config across restarts

- root cause: Technitium image ships /etc/dns as a real directory, so the
  build-time 'ln -sf /data/dns /etc/dns' created the symlink INSIDE it
  (/etc/dns/dns) instead of replacing it. Technitium kept writing to the
  ephemeral container directory and lost everything on restart.
- fix: add entrypoint.sh that runs at container start (after HA mounts
  volumes), removes the real /etc/dns dir, and symlinks it to /config/dns
  (the persistent addon_config mount). Seeds defaults on first run only.
- bump version to 15.4.2

technitium_dns/Dockerfile

@@ -1,12 +1,10 @@
 ARG BUILD_FROM=ghcr.io/hassio-addons/base:latest
 FROM technitium/dns-server:latest
 
-ENV DATA_DIR="/data/dns" \
+ENV DNS_SERVER_WEB_SERVICE_HTTPS_PORT=53443 \
-    DNS_SERVER_WEB_SERVICE_HTTPS_PORT=53443 \
     DNS_SERVER_WEB_SERVICE_ENABLE_HTTPS=false
 
-RUN mkdir -p /data/dns && \
+COPY entrypoint.sh /entrypoint.sh
-    ln -sf /data/dns /etc/dns
+RUN chmod +x /entrypoint.sh
 
-ENTRYPOINT []
+ENTRYPOINT ["/entrypoint.sh"]
-CMD ["dotnet", "DnsServerApp.dll"]

technitium_dns/config.yaml

@@ -1,5 +1,5 @@
 name: Technitium DNS
-version: 15.4.0
+version: 15.4.2
 slug: technitium_dns
 description: Technitium DNS Server add-on for Home Assistant
 arch:

technitium_dns/entrypoint.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+set -e
+
+# Technitium ships /etc/dns as a real directory in the image. We need it
+# to point at the persistent HA add-on config volume instead. Remove the
+# directory and replace with a symlink at runtime (after HA mounts volumes).
+
+DATA="/config/dns"
+
+mkdir -p "$DATA"
+
+if [ -d /etc/dns ] && [ ! -L /etc/dns ]; then
+    # Seed: copy any existing default config into the volume on first run
+    if [ -z "$(ls -A "$DATA" 2>/dev/null)" ]; then
+        cp -a /etc/dns/. "$DATA"/
+    fi
+    rm -rf /etc/dns
+fi
+
+ln -sf "$DATA" /etc/dns
+
+exec dotnet DnsServerApp.dll