~ overflow ~

Problem:

Some services keep dieing and there’s nothing much you can do about it, since they don’t restart automatically.

Those services could be httpd/apache, mysqld, sshd, etc

Solution:

This little script will do the job:

pstree | grep httpd | wc -l | awk ‘{if ($1 == 0)  system(“service httpd restart”) }’

in this example i’m checking if httpd (apache) is running.

broken down, pstree will list all your running processes,

grep httpd will search for “httpd” string on pstree,

wc -l will count the words from grep httpd, basically will return 0 or 1 if something was found,

and finally awk will check if wc -l is = 0 , meaning that the service / process in question is not running, then will perform the required action, on my example, service httpd restart which will restart apache.

You may also check it by port level as suggested by HTNet :

netstat -ln | grep “:80″ | wc -l | awk ‘{if ($1 == 0)  system(“service httpd restart”) }’

You could build up a little .sh file and put it on crontab to check it every minute or whatever you like.