Here’s how we set up Webmin cron

Cron is one particular of the most valuable utilities in Linux operating systems.

It makes it possible for operating scheduled tasks like disk space monitoring, program upkeep effortless.

In Webmin, there is a function to set up cron jobs that make customers schedule activity when they are out of workplace.

At Bobcares, we normally get requests from our shoppers to configure “Webmin cron” as portion of our Server Management Solutions.

Now, we’ll see how our Help Engineers add cron jobs in Webmin and repair the associated challenges with it.

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How we set up Webmin cron

Setting a cron job is a excellent way to automate a particular activity in Webmin.

Let’s see how we configure cron jobs in Webmin by following the measures beneath.

1. Initially, we log in to Webmin admin panel.

2. Subsequent, we navigate to Webmin> Technique> Scheduled Cron Jobs.

3. Then, we click the Generate a new scheduled cron job button.

4. In Execute cron job as field we choose the user & enter the script in Command field.

5. And beneath When to execute section we choose Instances and dates chosen beneath to enter the minutes, hours, days, months, weekdays.

6. Ultimately, to test the cron job click Save and Run Now.

Now, you can see all the listed scheduled cron jobs like this.

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Widespread errors & fixes just after setting cron job in Webmin

Even just after configuring cron job in Webmin, we normally see some widespread errors.

Let’s take a closer appear at every single one particular of them & how our Help Engineers fixed it.

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1. Incorrect command in cron

Lately one particular of our shoppers reported us that just after setting the command in cron job to automatically make Computer sleep & wake each and every day, it failed to run the activity. The command is:

/usr/sbin/rtcwake -m mem -l -t $(date +%s -d 'tomorrow 07:20')

This takes place mainly because the command entered was incorrect and it failed to execute.

So, to resolve the trouble we took the following measures.

1. Very first, we checked the cron log file to see the cron jobs.

 grep "CRON" /var/log/syslog

2. We identified that the cron command truncates like this:

/usr/sbin/rtcwake -m mem -l -t $(date +%s -d 'tomorrow 07:20')

3. In Webmin, specific character % is masked automatically as %. So, we corrected the command as:

/usr/sbin/rtcwake -m mem -l -t $(date +%s -d 'tomorrow 07:20')

4. Ultimately, we restarted the service.

systemctl restart crond.service

That fixed the trouble & the user could execute the cron job.

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2. Incorrect Permission

Similarly, a further consumer approached us with a trouble just after executing crontab, it resulted in an error like “/usr/bin/crontab: Permission denied”.

Frequently this error takes place when the corresponding user doesn’t have the permission to execute the cron job.

As a outcome, it prevents the Webmin cron module to perform appropriately.

So, to resolve this error we performed the following measures.

1. Very first, we checked the list of customers.

ls /var/spool/cron/crontabs

2. Subsequent, we checked the user permission by operating this command:

ls /usr/bin/crontab

3. By analyzing, we identified that the user didn’t have any permission. So, we granted permissions by operating this command:

chmod 2755 /usr/bin/crontab

4. Ultimately, we restarted the solutions.

That fixed the trouble & the user could run the cron job with out any failure.

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3. Broken PHP module

In some cases crontab does not perform if the PHP module is not appropriately installed. PHP script executed with a cron job demands a particular php.ini file.

To execute cron job appropriately we installed PHP on the Webmin server by operating the command:

apt-get set up php7.0-cli

When PHP installed, we executed the PHP command & the cron job like this.

php /var/www/instance.com/public_html/crons.php

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[Having trouble after setting cron job in Webmin? We’;ll fix it for you.]

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Conclusion

To be much more precise, the cron job support customers to schedule tasks that make it simpler. Now, we saw how our Help Engineers configured Webmin cron & fixed the leading 3 widespread errors associated to it.

The post Right here’s how we set up Webmin cron appeared initial on Bobcares.