[SOLVED] run cron using supervisord on docker alpine image

Issue

I have a docker image part of a service and I am testing the possibility to add a cron job

I have setup the Dockerfile using with a crontab that should run a script (that for now should just output the date).

supervidord starts and spawns cron, but I see no regular outputs of dates...neither on terminal nor on the log file.

the Dockerfile is:

FROM docker.io/python:3.6-alpine
ENV PYTHONUNBUFFERED 1
WORKDIR /opt/app-root/src

RUN apk update && apk add --no-cache bash supervisor \
    && rm -rf /var/cache/apk/*





# Copy Scripts
COPY mirror/src/ $WORKDIR
COPY mirror/src/supervisord.conf /etc/supervisor/conf.d/supervisord.conf

RUN chmod +x ./entrypoint.sh
RUN chmod +x ./run.sh
RUN touch logs.log
RUN /usr/bin/crontab ./crontab.txt



CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/conf.d/supervisord.conf"]

the supervisord.conf file is:

[supervisord]
nodaemon = true

[program:cron]
command=crond -f
user=root
autostart=true
autorestart=true

crontab.txt is:

*/10 * * * * * bash ./run.sh >logs.log 2>&1

and the run.sh script is:

#!/bin/bash
echo `date +%Y%m%d_%H%M%S

The only output I see on terminal is:

crond[7]: USER root pid   8 cmd * bash ./run.sh >logs.log 2>&1

what's wrong with my setup?

Solution

found a way, posting my solution:

Dockerfile edited:

RUN chmod +x ./run.sh

# Setup CRON to update databases
RUN touch crontab.tmp \
    && echo '*/10 * * * * /opt/app-root/src/run.sh update > /dev/null' > crontab.tmp \
    && crontab crontab.tmp \
    && rm -rf crontab.tmp


# Start Server
EXPOSE 8080


CMD ["/usr/bin/supervisord", "-c", "/etc/supervisor/supervisord.conf"]

and supervisord conf:

[supervisord]
nodaemon = true
logfile = /dev/null
logfile_maxbytes = 0
pidfile = /run/supervisord.pid

[program:mirror]
command = /bin/bash -c "/opt/app-root/src/run.sh"
stdout_logfile = /dev/stdout
stdout_logfile_maxbytes=0
stderr_logfile = /dev/stderr
stderr_logfile_maxbytes=0
user = root
autostart = true
autorestart = true
startretries=10
priority = 20

[program:cron]
command = /bin/bash -c "/usr/sbin/crond -f -d 0"
stdout_logfile = /dev/stdout
stdout_logfile_maxbytes=0
stderr_logfile = /dev/stderr
stderr_logfile_maxbytes=0
user = root
autostart = true
autorestart = true
priority = 20

In this example the container was exiting too quickly so added a startretries option.

Answered By - bruvio

Answer Checked By - Willingham (WPSolving Volunteer)