A bash script to restart Apache if the free memory is too low

"Self, I'm having terrible problems with Apache eating up all of my memory and crashing MySQL or the entire server itself, and I know reloading Apache frees up the memory every time. I know that the right thing to do is to properly troubleshoot what's causing Apache to consume all this memory, but I'm in a pinch and out of time and need something quick and dirty to keep things running. Why not write a bash script to check how much memory is free and reload Apache if it gets below a certain threshold? And have it log what it does each time it runs?"

As a sysadmin, we strongly discourage things like this when other people do them. This is a terrible script. You shouldn't be running this script. But sometimes you need to do terrible things and run terrible scripts like this. So here it is:

#!/bin/bash FREE_MEMORY=$(free -m | grep Mem | cut -d' ' -f 28) THRESHOLD=150 LOG=low-memory-fixer.log APACHE_STATUS=$(service httpd status) if [ "$FREE_MEMORY" -lt "$THRESHOLD" ] then echo -e "Time to reload Apache. Current memory value is $FREE_MEMORY, lower than the current threshold of $THRESHOLD. Reloading Apache. Date is $(date)." >> $LOG service httpd reload echo -e "Apache status is $APACHE_STATUS. Date is $(date)." >> $LOG else echo -e "Memory is still good. Current memory value is $FREE_MEMORY, higher than the current threshold of $THRESHOLD. Nothing to do here! Date is $(date)." >> $LOG fi

You'll want to create the log file in the same directory the script is running in - "touch low-memory-fixer.log" is sufficient. If you want to set up a cronjob that runs this script every 10 minutes, run "crontab -e" as the user this being run by and add a line like this: "*/10 * * * * bash /path/to/the/script/goes/here/low-memory-fixer.sh".

This script was written in five minutes. This script is one of the worst solutions I've seen in my professional career. Don't run this script. All humor aside, if you're running this script, you really need to dig into Apache and find out what's going on, or to get someone who can do that to look at your server.