In this section you can find sample implementations to deploy Cron servers.
It will be added to each brief assistance to Design Decisions, a process and a sample implementation (customization required) pointed out.
Bash Cron Job Deployment
- Why bash?
- It is usually available,
- easy to understand and
- stable
- process
- Caveat: definition of Cron in the script or config depending on the environment
- Decide is what to do according to set environment variables
- Write the crontab
- Cleanup temporary files
- Deployment
- The bash script is expected by the configuration management system under a specific path and
- called parameterized plain or by appointment
- When it comes to the server by a cron server (ROLES contains "cron") is written a defined crontab
- This also assumes that the Cron to be run, are actually stored in the specified directory and executable.
Example (adjustment necessary)
#!/bin/bash
if [ -z "$ROLES" ]; then
echo 'Roles not set!'
exit 1
fi
# Main
if [ "$ROLES" = "cron" ]; then
# write crontab file
echo '#Cron by install.sh' > tempfile
echo '00 09 * * 1-5 echo hello' >> tempfile
echo '00 15 * * * echo bla' >> tempfile
# cron example with custom logging
echo "* * * * * date >> /var/log/application/cron.log && cd /var/www/ && /usr/bin/php cron.php >> /var/log/application/cron.log 2>&1" >> tempfile
# Update crontab
crontab tempfile
# Clean Up
rm tempfile
fi
echo 'Done successfully.'