Docker - docker-compose - postgres image

Question

I'm using the postgres:latest image, and creating backups using the following command

pg_dump postgres -U postgres > /docker-entrypoint-initdb.d/backups/redmine-$(date +%Y-%m-%d-%H-%M).sql

and it's running periodically using crontab

*/30 * * * * /docker-entrypoint-initdb.d/backup.sh

However, on occasion I might need to run

docker-compose down/up

for whatever reason

The problem I always need to manually run /etc/init.d/cron start whenever I restart the container. This is a bit of a problem because it's difficult to remember to do, and if I (or anyone else) forgets this, backups wont be made

According to the documentation, scripts ending with *.sql and *.sh inside the /docker-entrypoint-initdb.d/ are run on container startup (and they do) However, if I put /etc/init.d/cron start inside a executable .sh file, the other commands inside that file are executed and I've verified that. But the cron service does not start, probably because the /etc/init.d/cron start inside the executable file does not execute successfully

I would appreciate any suggestion for a solution

Can you provide your dockerfile or atleast let us know the base image you used (ubuntu/centos) ? — mchawre
– mchawre, Commented Jun 19, 2019 at 11:25

Jite · Accepted Answer · 2019-06-19 11:24:47Z

2

You will want to keep your docker containers as independent of other services as possible, I would recommend that you instead of running the cronjob in the container do it on the host, that way it will run even if the container is restarted (weather automatically or manually).

If you really really feel the need for it, I would build a new image with the postgres image as base, and add the cron right from there, that way it is in the container already from start, without any extra scripts needed. Or even create another image just to invoke the cronjob and connect via the docker network.

answered Jun 19, 2019 at 11:24

Jite

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3 Comments

isebarn Over a year ago

I want the the entire functionality of the container for administration to be contained to only having to execute docker-compose up and docker-compose down, so if I go on vacation, quit or die, if for some reason the application is moved to another VM, the backups will still be made as long is the container is started and not subject to other admins reading the documentation

Jite Over a year ago

Then I would recommend adding a cron-job container to run parallel with your other in the compose file.

isebarn Over a year ago

Thank you, I will

b0gusb · Accepted Answer · 2019-06-19 13:01:16Z

1

Expanding on @Jite's answer, you could run pg_dump remotely in a different container using the --host option

This image, for example, provides a minimal environment with psql client and dump/restore utilities

answered Jun 19, 2019 at 13:01

b0gusb

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1 Comment

isebarn Over a year ago

I like this. I want the entire functionality to be illustrated in the docker-compose file

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