Describe the process to start and restart apache on CENTOS command line. Also describe how to have apache start automatically when the server is rebooted. Solution In order to stop or restart the Apache HTTP Server, you must send a signal to the running httpd processes. There are two ways to send the signals. First, you can use the unix kill command to directly send signals to the processes. You will notice many httpd executables running on your system, but you should not send signals to any of them except the parent, whose pid is in the PidFile. Start: Starting httpd using the apachectl control script sets the environmental variables in /etc/sysconfig/httpd and starts httpd. You can also set the environment variables using the init script. You can also start httpd using /sbin/service httpd start. This starts httpd but does not set the environment variables. If you are using the default Listen directive in httpd.conf, which is port 80, you will need to have root privileges to start the apache server. Restart: Signal: HUP apachectl -k restart Sending the HUP or restart signal to the parent causes it to kill off its children like in TERM, but the parent doesn\'t exit. It re-reads its configuration files, and re-opens any log files. Then it spawns a new set of children and continues serving hits. If you want your server to continue running after a system reboot, you should add a call to apachectl to your system startup files (typically rc.local or a file in an rc.N directory). This will start Apache as root. Before doing this ensure that your server is properly configured for security and access restrictions. The apachectl script is designed to act like a standard SysV init script; it can take the arguments start, restart, and stop and translate them into the appropriate signals to httpd. So you can often simply link apachectl into the appropriate init directory. But be sure to check the exact requirements of your system. .

1. Describe the process to start and restart apache on CENTOS command line. Also describe how
to have apache start automatically when the server is rebooted.
Solution
In order to stop or restart the Apache HTTP Server, you must send a signal to the running httpd
processes. There are two ways to send the signals. First, you can use the unix kill command to
directly send signals to the processes. You will notice many httpd executables running on your
system, but you should not send signals to any of them except the parent, whose pid is in the
PidFile.
Start: Starting httpd using the apachectl control script sets the environmental variables in
/etc/sysconfig/httpd and starts httpd. You can also set the environment variables using the init
script.
You can also start httpd using /sbin/service httpd start. This starts httpd but does not set the
environment variables. If you are using the default Listen directive in httpd.conf, which is port
80, you will need to have root privileges to start the apache server.
Restart:
Signal: HUP
apachectl -k restart
Sending the HUP or restart signal to the parent causes it to kill off its children like in TERM, but
the parent doesn't exit. It re-reads its configuration files, and re-opens any log files. Then it
spawns a new set of children and continues serving hits.
If you want your server to continue running after a system reboot, you should add a call to
apachectl to your system startup files (typically rc.local or a file in an rc.N directory). This will
start Apache as root. Before doing this ensure that your server is properly configured for security
and access restrictions.
The apachectl script is designed to act like a standard SysV init script; it can take the arguments
start, restart, and stop and translate them into the appropriate signals to httpd. So you can often

2. simply link apachectl into the appropriate init directory. But be sure to check the exact
requirements of your system.