Running apache and cron in docker - apache

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

Answer 2

The problem is that you're running crond -f, without telling bash to run it in the background, basically keeping bash waiting for crond to exit to continue running the script. There's two solutions for this:
Remove the -f flag (that flag causes crond to run in the foreground).
Add & at the end of the crond line, after -l 8 (I wouldn't recommend this).
Also, I'd start apache with exec:
exec httpd -D FOREGROUND
Otherwise /startup/script.sh will remain running, while it's not doing anything useful anymore anyway. exec tells bash to replace the current process with the command to execute.