Docker – no crontab for root

crondocker

My Dockerfile appears to build correctly (it tells me so). When I run the container, I get the below error message. I have tried running the commands (CMD) with and without the service's directory.

crontab.sh basically writes a cron schedule to a text file (cron.jobs) and then imports the text file to crontab.

Dockerfile:

FROM node:0.10
MAINTAINER Tom

VOLUME /var/log/

RUN mkdir /pulse
ADD . /pulse
WORKDIR /pulse

RUN apt-get update && apt-get install -y cron

ADD *.sh /pulse/
RUN chmod 750 /pulse/crontab.sh && chmod 750 /pulse/

RUN chmod 644 /etc/crontab

CMD cron -f
CMD touch /var/log/cron.log && sh /pulse/crontab.sh && tail -f /var/log/cron.log
CMD cron /pulse/cron.jobs
CMD crontab -l

edited to add crontab.sh

crontab.sh (some crons have been removed):

#!/bin/bash

cat <<- 'EOF' > cron.jobs

0 * * * * node /pulse/scripts/awsPulseTest.js > /tmp/awsPulseTest.log 2>&1

EOF

crontab cron.jobs

Error:

no crontab for root

Side notes:

  • Pulse is the name of the service.
  • The version of node is old due to the service, this will be upgraded.
  • The service is essentially for cron jobs in node

Best Answer

It's an issue with the dockerfile (rather than the commands in the file). Only one CMD is run (the last one) - see https://docs.docker.com/engine/reference/builder/#cmd

There can only be one CMD instruction in a Dockerfile. If you list more than one CMD then only the last CMD will take effect.

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