Running apache and cron in docker

Question

I understood there should be only one process running on foreground in a docker container. Is there any chance of running both apache and cron together in foreground? A quick search says there is something called supervisord to achieve this. But is there any other method using Entrypoint script or CMD?

Here is my Dockerfile

FROM alpine:edge
RUN  apk update && apk upgrade
RUN echo "http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk   /repositories
RUN  apk add \
     bash \ 
     apache2 \
     php7-apache2 \
     php7 \
     curl \
     php7-mysqli \
     php7-pdo \
     php7-pdo_mysql

 RUN cp /usr/bin/php7 /usr/bin/php
 RUN mkdir /startup
 COPY script.sh /startup
 RUN chmod 755 /startup/script.sh
 ENTRYPOINT ["/startup/script.sh"]

The content of script.sh is pasted below

#!/bin/bash
# start cron
/usr/sbin/crond -f -l 8
# start apache
httpd -D FOREGROUND

When the docker is run with this image only crond is running and most interestingly when I kill the cron then apache starts and running in the foreground.

I am using aws ecs ec2 to run the docker container using task definition and a service.

Answer 1

Docker container is running while main process inside it is running. So if you want to run two services inside docker container, one of them has to be run in a background mode.

I suggest to get rid of scrip.sh at all and replace it just with one CMD layer:

CMD ( crond -f -l 8 & ) && httpd -D FOREGROUND

The final Dockerfile is:

FROM alpine:edge
RUN  apk update && apk upgrade
RUN echo "http://dl-cdn.alpinelinux.org/alpine/edge/testing" >> /etc/apk/repositories
RUN  apk add \
     bash \ 
     apache2 \
     php7-apache2 \
     php7 \
     curl \
     php7-mysqli \
     php7-pdo \
     php7-pdo_mysql

RUN cp /usr/bin/php7 /usr/bin/php
CMD ( crond -f -l 8 & ) && httpd -D FOREGROUND