meteor with MUP: mongodump in bash script used in a cronjob

Question

I'm running a Meteor application using MUP for deployment. So on the server I created a backup-script, which looks like this:

#!/bin/sh

#export mongodump
docker exec -it mongodb mongodump --archive=/root/mongodump.gz --gzip

#create datestring
filedate=$(date +%Y-%m-%d_%H-%M-%S)

#put dump export in file
docker cp mongodb:/root/mongodump.gz mongodump_$filedate.gz

All good so far and all works as expected.

The weird problem starts when I add the script to a cronjob

0 1 * * * /home/user1/backup.sh

This also works, i.e. the mongodump.gz is added properly. However, for any reason the backup is always the same (matching SHA-256-HASH) as long as the cronjob creates the backup. When I run the backup script manually again, SHA-Hash and filesize of the dump changes. The next time the cronjob backup is called, it is the same as the previous created backup.

Any ideas what's happening here?

Answer 1

It's difficult to say what might be going wrong in your backup script, but for the same setup (backing up a mup-deployed meteor database via a cronjob), I use this script and it works well:

#!/bin/bash

# fail on error
set -e

# NOTE: no -it in docker command, see
# https://stackoverflow.com/questions/43099116/error-the-input-device-is-not-a-tty
docker exec mongodb mongodump -d mydb -o /data/db/ --gzip -- -j 1
mkdir -p /home/ubuntu/backup/

sudo rm -rf /home/ubuntu/backup/mydb
sudo mv /var/lib/mongodb/mydb /home/ubuntu/backup
sudo chown ubuntu:ubuntu -R /home/ubuntu/backup/mydb

A couple of things to note:

• As the note indicates I had to remove the -it from the docker command to avoid issues with the terminal not being a tty, see here.
• There is no need to use docker cp, since mup uses a persistent folder inside the container that can be accessed from the host directly.