fix service health check, and properly disable coredns

root/etc/s6-overlay/s6-rc.d/init-wireguard-confs/run

@@ -162,8 +162,7 @@ else
     echo "**** No client conf found. Provide your own client conf as \"/config/wg0.conf\" and restart the container. ****"
     sleep infinity
   fi
-  echo "**** Disabling CoreDNS ****"
-  rm -rf /etc/services.d/coredns
+  printf "false" > /run/s6/container_environment/USE_COREDNS
 fi
 
 # set up CoreDNS

root/etc/s6-overlay/s6-rc.d/svc-coredns/run

@@ -1,16 +1,20 @@
 #!/usr/bin/with-contenv bash
 
 if netstat -apn | grep -q ":53 "; then
-  echo "Another service is using port 53, disabling CoreDNS"
-  sleep infinity
+    USE_COREDNS="false"
+fi
+
+if [[ ${USE_COREDNS} == "false" ]]; then
+    s6-notifyoncheck -d -n 300 -w 1000 -c "echo **** Disabling CoreDNS ****" \
+        sleep infinity
 elif grep -q "health" /config/coredns/Corefile; then
-  exec \
-    s6-notifyoncheck -d -n 300 -w 1000 -c "redirfd -w 1 /dev/null curl -s http://localhost:8080/health" \
-      cd /config/coredns \
-      /app/coredns -dns.port=53
-else  
-  exec \
-    s6-notifyoncheck -d -n 300 -w 1000 -c "nc -z -u 127.0.0.1 53" \
-      cd /config/coredns \
-      /app/coredns -dns.port=53
+    exec \
+        s6-notifyoncheck -d -n 300 -w 1000 -c "redirfd -w 1 /dev/null curl -s http://localhost:8080/health" \
+            cd /config/coredns \
+            /usr/bin/coredns -dns.port=53
+else
+    exec \
+        s6-notifyoncheck -d -n 300 -w 1000 -c "nc -zu localhost 53" \
+            cd /config/coredns \
+            /usr/bin/coredns -dns.port=53
 fi