autonomous dns

Dockerfile

@@ -1,4 +1,4 @@
-FROM alpine:3.13.2 AS build
+FROM alpine:3.13.3 AS build
 ENV EMAIL monit@sutty.nl
 
 RUN apk add --no-cache tzdata
@@ -7,33 +7,33 @@ COPY ./monitrc /etc/monitrc
 RUN chmod 600 /etc/monitrc
 RUN sed -re "s/@@EMAIL@@/${EMAIL}/" -i /etc/monitrc
 
-FROM alpine:3.13.2
+FROM alpine:3.13.3
 MAINTAINER "f <f@sutty.nl>"
 
 # TODO: We don't want to receive lots of email, so we'll change this to
 # a pingy instance that will also work as a status site.
 ENV EMAIL monit@sutty.nl
 
+# Sutty's repository
+RUN echo https://alpine.sutty.nl/alpine/v3.13/sutty >> /etc/apk/repositories
+RUN wget https://alpine.sutty.nl/alpine/sutty.pub -O /etc/apk/keys/alpine@sutty.nl-5ea884cd.rsa.pub
+
 # Install monit and remove default config
-RUN apk upgrade --no-cache
+RUN apk add --no-cache tini monit knsupdate
-RUN apk add --no-cache tini monit
 COPY --from=build /usr/share/zoneinfo/UTC /etc/localtime
 
 # Create directories
 RUN install -dm 2750 -o root -g root /etc/monit.d
 RUN install -dm 2750 -o root -g root /var/lib/monit
 
-# Install config. monit.conf~ will be activated after allow_networks
+# Install config
-# runs.
 COPY --from=build /etc/monitrc /etc/monitrc
+COPY ./nsupdate.sh /usr/local/bin/nsupdate
+COPY ./whatsmyip6.sh /usr/local/bin/whatsmyip6
 
 # Allow access to the web GUI
 EXPOSE 2812
 
-# Sutty's repository
-RUN echo 'https://alpine.sutty.nl/alpine/v3.13/sutty' >> /etc/apk/repositories
-RUN wget https://alpine.sutty.nl/alpine/sutty.pub -O /etc/apk/keys/alpine@sutty.nl-5ea884cd.rsa.pub
-
 # Use tini as init
 ENTRYPOINT ["/sbin/tini", "--"]
 

monitrc

@@ -13,4 +13,9 @@ set httpd port 2812
   allow localhost
   allow 172.0.0.0/8
 
+check program nsupdate
+  with path "/usr/local/bin/nsupdate"
+  every 1 cycle
+  if status = 0 then unmonitor
+
 include /etc/monit.d/*.conf

nsupdate.sh

@@ -0,0 +1,22 @@
+#!/bin/sh
+
+# Registers the local IPv6 address to the DNS
+
+IP6="`whatsmyip6`"
+KNOT="${KNOT:-${IP6}}"
+
+test -z "${IP6}" && exit 1
+test -z "${KNOT}" && exit 1
+test -z "${DOMAIN}" && exit 1
+
+knsupdate <<DNS
+server ${KNOT}
+zone ${DOMAIN}.
+origin ${DOMAIN}.
+ttl 60
+add ${HOSTNAME} AAAA ${IP6}
+send
+quit
+DNS
+
+exit $?

whatsmyip6.sh

@@ -0,0 +1,3 @@
+#!/bin/sh
+
+ip address show ${1:-eth0} | grep inet6 | grep global | tr -s " "  | cut -d " " -f 3 | cut -d / -f 1