Fix issues with creating orphan processes

By using bash (which plays nicely by reparenting orphan processes)

Dockerfile

@@ -1,13 +1,14 @@
 FROM registry.lan/alpine:3.10
 
-
 RUN apk -v --update add \
+        bash \
         python \
         py-pip \
         groff \
         less \
         mailcap \
         jq \
+        wget \
         && \
     pip install --upgrade awscli==1.14.5 s3cmd==2.0.1 python-magic && \
     apk -v --purge del py-pip && \
@@ -17,7 +18,8 @@ COPY ./update-dns.sh /usr/local/bin/
 RUN chmod +x /usr/local/bin/update-dns.sh
 
 RUN mkdir -p /etc/cron.d/
-RUN echo -e "*/10 * * * * update-dns.sh\n" > /etc/cron.d/dns-cron
+RUN echo -e "*/10 * * * * /bin/bash update-dns.sh >> /var/log/cron.log 2>&1" > /etc/cron.d/dns-cron
 RUN crontab /etc/cron.d/dns-cron
+RUN touch /var/log/cron.log
 
-CMD ["crond", "-f"]
+CMD crond && tail -f /var/log/cron.log

update-dns.sh

@@ -1,4 +1,4 @@
-#!/bin/sh
+#!/bin/bash
 
 set -eux
 
@@ -28,3 +28,5 @@ EOM
 )
 
 aws route53 change-resource-record-sets --hosted-zone-id "${zone_id}" --change-batch "$batch"
+
+wait