Being a Linux and Cloud Engineer I happen to work on building many servers which should be reliable, and I come across few customers who just want the server to be build and least work in managing them. So, I came up to a solution to start services by themselves if the apache web server goes down using cron and if loop. The following script serves the purpose.

First let’s create a directory to put all the custom scripts to be put in there.

mkdir /scripts/

cd /scripts/

Let’s create a script and call it as apachechk.sh

touch apachechk.sh

Provide it with execution permission.

chmod +x apachechk.sh

Then let’s add the following entry to our root user’s cron

crontab -e
*/5 * * * * /scripts/apachechk.sh >/dev/null 2>&1

Now, let’s paste the following lines to the script file on our Debian/Ubuntu based system.

#!/bin/bash
#This script will check if Apache process is down in Debian/Ubuntu based system and restarts it automatically.
#Script is located at https://helpinlinux.com/shell-script-to-auto-restart-apache-httpd-when-it-goes-down-dead
#Let's declare RESTART, PGREP and HTTPD command names.
RESTART="service apache2 restart"
PGREP="/usr/bin/pgrep"
HTTPD="apache2"
# find httpd pid
$PGREP ${HTTPD}
#Check if the process retruns not value[apache2 not running].
if [ $? -ne 0 ]
then
 # restart apache
 $RESTART
fi

If you are using CentOS/Redhat based system please add the following code to your apachechk.sh file.

#!/bin/bash
#This script will check if Apache process is down in Redhat/CentOS based system and restarts it automatically.
#Script is located at https://helpinlinux.com/shell-script-to-auto-restart-apache-httpd-when-it-goes-down-dead
#Let's declare RESTART, PGREP and HTTPD command names.
RESTART="service httpd restart"
PGREP="/usr/bin/pgrep"
HTTPD="httpd"
# find httpd pid
$PGREP ${HTTPD}
#Check if the process retruns not value[httpd not running].
if [ $? -ne 0 ]
then
 # restart apache
 $RESTART
fi

Reference: http://bash.cyberciti.biz/web-server/restart-apache2-httpd-shell-script/