mjhjmtu

I have the following file execute-backup-from-container.sh. The content of this file is:

#!/bin/bash
FILE=minime.sql.`date +"%Y%m%d".gz`
CONTAINER='mysql_01'
SCRIPT_ON_CONTAINER='/container-mysql-dump.sh'

$OUTPUT=$(docker exec $CONTAINER /$SCRIPT_ON_CONTAINER)

echo "=============="
echo "$CONTAINER:/$FILE"
echo "=============="
docker cp "$CONTAINER:/$FILE" backup-data/

When I run crontab -e I am putting the following:
0 5 * * 1 /home/me/projects/execute-backup-from-container.sh
This means that the execute-backup-from-container.sh should be executed every day at 5:00 am.

The problem is that the script is not executed at all.

So what on earth is the problem? Why is it not executed?

The cron fields corresponding to your entry mean:

minute: 0 
hour: 5 
day of month: * 
month: * 
day of week: 1 
command: /home/me/projects/execute-backup-from-container.sh

which translate in English to: Mondays at 5am (any day of the month, any month).

If you want it to be executed:

every day at 5:00 am

then you want that 5th field to be a *:

0 5 * * * /home/me/projects/execute-backup-from-container.sh

Did you check that the file is set to be executable? Here is an example of marking a script as executable:

$ ls -l test.sh
-rw-r--r-- 1 ahill ahill 0 Mar 23 19:30 test.sh
$ chmod +x test.sh
$ ls -l test.sh
-rwxr-xr-x 1 ahill ahill 0 Mar 23 19:30 test.sh

The next thing to check is the environment. cron jobs inherit no environment by default. The "fix" is discussed here:
How can I run a cron command with existing environmental variables?

One of the reasons that the environment is a big deal is that cron might not even find bash! see: https://www.digitalocean.com/community/questions/why-is-cron-not-running-my-sh-script

If you still cannot figure it out, I would do a test: Change your cron job from:

0 5 * * * /home/me/projects/execute-backup-from-container.sh

to:

0 5 * * * /home/me/projects/execute-backup-from-container.sh >> ~/script_errors.log 2>&1 

What will happen: the next time cron launches the job, error messages produced will be dumped into the text file script_errors.log. (change the path to the script_errors.log file to whatever seems appropriate, but make sure the path exists, though the file does not need to.)

I also noticed something in the OP that might be the real problem: the word "container." If the script is inside of a Docker container, then this is likely the solution:
https://www.ekito.fr/people/run-a-cron-job-with-docker/

After keeping into account all the answers, the last issue was in the last line:

docker cp "$CONTAINER:/$FILE" backup-data/ 

The last line should have been

docker cp "$CONTAINER:/$FILE" docker-projects/mysql/backup-data/ 

Thank you all for your support.