Crons parallelization management

[Nuranto]

Summary (*)

Magento 2.4.4

Crons groups that can be parallelized are launched via the main cron:run command. This can be a problem if that process is taking too long.

Examples (*)

Use case :

Let's say you have one group group_example that have use_separate_process to 1, where there is a job job_example that need to be executed every minutes.
Let's also say that the others groups are taking 10min to execute (long reindex, or whatever).

It means that the command /usr/local/bin/php /var/www/html/bin/magento cron:run --group=group_example --bootstrap=standaloneProcessStarted=1 is run every 10 minutes.

Which means job_example may not be executing for 10 minutes.

(the number "10" minutes is arbitrary for the example, I'm sure sometimes it could be a lot more)

Proposed solution

It would be more safe and logical if the separate processes were not launched by the cron:run command.
Those parallelization-friendly groups should be added to crontab by cron:install directly.

Also, other subject but a linked one, we should probably prevent cron:run to be launched when another is already running to avoid accumulation risks. cron:run can be launched with flock for instance : flock -w 0 /tmp/magento.cron.lock /usr/local/bin/php {magentoRoot}bin/magento cron:run

Of course, we can modify all this manually via di.xml, but maybe it should be native.

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[m2-assistant]

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Same issue on 2.4.3-p2 version

[engcom-Lima]

Hi @Nuranto,
Thanks for the collaboration and reporting the issue.
Can you please provide us with the exact steps to reproduce this issue.

Thanks!

[m2-assistant]

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[Nuranto]

Hi @engcom-Lima,

1. Create a custom cron (default group) that just sleep for 30 minutes. Configure it for execution every minutes
2. Run crons

Expected behaviour

After a 30 minutes, Only one cron process is started/running

Actual behaviour

After 30 minutes, we have 30 cron processes running, possibly consuming all resources if sleep is being replaced by actual code.

[engcom-Lima]

Hi @Nuranto

Thanks for the input,
I tried to reproduce this issue with latest 2.4-develop instance however the issue is still not reproducible

Steps followed to reproduce the issue

1. Install latest 2.4-develop instance
2. Create custom cron that will just sleep for sometime(tried with 5 mins) group=default
3. Configure group to run every minute and set use_separate_process to 1

Only one process was started and cannot see more that one process running

Do let me know if I have missed any steps will reverify again

Thanks

[Nuranto]

Hello @engcom-Lima

You need to set use_separate_process to 0 to reproduce the issue.

[engcom-Lima]

Hi @Nuranto,
Thank you for the reply

Reverified with again and the issue is reproducible,

IMAGE UPLOAD

Hence confirming the issue

Thanks