Installing Apache2 With PHP5 And MySQL Support On CentOS 5.3 (LAMP)

LAMP is short for Linux, Apache, MySQL, PHP. This tutorial shows how you can install an Apache2 webserver on a CentOS 5.3 server with PHP5 support (mod_php) and MySQL support.

I do not issue any guarantee that this will work for you!

1 Preliminary Note

In this tutorial I use the hostname server1.example.com with the IP address 192.168.0.100. These settings might differ for you, so you have to replace them where appropriate.

2 Installing MySQL 5.0

To install MySQL, we do this:

yum install mysql mysql-server

Then we create the system startup links for MySQL (so that MySQL starts automatically whenever the system boots) and start the MySQL server:

chkconfig --levels 235 mysqld on
/etc/init.d/mysqld start

Run

mysqladmin -u root password yourrootsqlpassword
mysqladmin -h server1.example.com -u root password yourrootsqlpassword

to set a password for the user root (otherwise anybody can access your MySQL database!).

3 Installing Apache2

Apache2 is available as a CentOS package, therefore we can install it like this:

yum install httpd

Now configure your system to start Apache at boot time...

chkconfig --levels 235 httpd on

... and start Apache:

/etc/init.d/httpd start

Now direct your browser to http://192.168.0.100, and you should see the Apache2 placeholder page:

Apache's default document root is /var/www/html on CentOS, and the configuration file is /etc/httpd/conf/httpd.conf. Additional configurations are stored in the/etc/httpd/conf.d/ directory.

4 Installing PHP5

We can install PHP5 and the Apache PHP5 module as follows:

yum install php

We must restart Apache afterwards:

/etc/init.d/httpd restart

5 Testing PHP5 / Getting Details About Your PHP5 Installation

The document root of the default web site is /var/www/html. We will now create a small PHP file (info.php) in that directory and call it in a browser. The file will display lots of useful details about our PHP installation, such as the installed PHP version.

vi /var/www/html/info.php

<?php phpinfo(); ?>

Now we call that file in a browser (e.g. http://192.168.0.100/info.php):

As you see, PHP5 is working, and it's working through the Apache 2.0 Handler, as shown in the Server API line. If you scroll further down, you will see all modules that are already enabled in PHP5. MySQL is not listed there which means we don't have MySQL support in PHP5 yet.

6 Getting MySQL Support In PHP5

To get MySQL support in PHP, we can install the php-mysql package. It's a good idea to install some other PHP5 modules as well as you might need them for your applications. You can search for available PHP5 modules like this:

yum search php

Pick the ones you need and install them like this:

yum install php-mysql php-gd php-imap php-ldap php-odbc php-pear php-xml php-xmlrpc

Now restart Apache2:

/etc/init.d/httpd restart

Now reload http://192.168.0.100/info.php in your browser and scroll down to the modules section again. You should now find lots of new modules there, including the MySQL module:

7 phpMyAdmin

phpMyAdmin is a web interface through which you can manage your MySQL databases.

First we enable the RPMforge repository on our CentOS system as phpMyAdmin is not available in the official CentOS 5.3 repositories:

On x86_64 systems:

wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm
rpm -Uvh rpmforge-release-0.3.6-1.el5.rf.x86_64.rpm

On i386 systems:

wget http://packages.sw.be/rpmforge-release/rpmforge-release-0.3.6-1.el5.rf.i386.rpm
rpm -Uvh rpmforge-release-0.3.6-1.el5.rf.i386.rpm

phpMyAdmin can now be installed as follows:

yum install phpmyadmin

Now we configure phpMyAdmin. We change the Apache configuration so that phpMyAdmin allows connections not just from localhost (by commenting out the <Directory "/usr/share/phpmyadmin"> stanza):

vi /etc/httpd/conf.d/phpmyadmin.conf

# # Web application to manage MySQL # #<Directory "/usr/share/phpmyadmin"> # Order Deny,Allow # Deny from all # Allow from 127.0.0.1 #</Directory> Alias /phpmyadmin /usr/share/phpmyadmin Alias /phpMyAdmin /usr/share/phpmyadmin Alias /mysqladmin /usr/share/phpmyadmin

Next we change the authentication in phpMyAdmin from cookie to http:

vi /usr/share/phpmyadmin/config.inc.php

[...] /* Authentication type */ $cfg['Servers'][$i]['auth_type'] = 'http'; [...]

Restart Apache:

/etc/init.d/httpd restart

Afterwards, you can access phpMyAdmin under http://192.168.0.100/phpmyadmin/:

Source : http://www.howtoforge.com/installing-apache2-with-php5-and-mysql-support-on-centos-5.3-lamp

INSTALL AND CONFIGURE NTP SERVER ON CENTOS 5

Quick setup instructions to install and configure an NTP server:

# yum install ntp

# chkconfig ntpd on

Add the servers you want to sync from in /etc/ntp.conf. Sample:

server 0.centos.pool.ntp.org
server 1.centos.pool.ntp.org
server 2.centos.pool.ntp.org

# service ntpd start

# ntpq -pn

-H

nohup | Execute Commands After You Exit From a Shell Prompt

Most of the time you login into remote server via ssh. If you start a shell script or command and you exit (abort remote connection), the process / command will get killed. Sometime job or command takes a long time. If you are not sure when the job will finish, then it is better to leave job running in background. However, if you logout the system, the job will be stopped. What do you do?

nohup command

Answer is simple, use nohup utility which allows to run command./process or shell script that can continue running in the background after you log out from a shell :

nohup Syntax :

nohup command-name &

Where,

• command-name : is name of shell script or command name. You can pass argument to command or a shell script.
• & : nohup does not automatically put the command it runs in the background; you must do that explicitly, by ending the command line with an & symbol.

nohup command examples

1) Login to remote server

$ ssh user@remote.server.com

2) Execute script called pullftp.sh

# nohup pullftp.sh &

Type exit or press CTRL + D exit from remote server.

# exit

3) Find all programs and scripts with setuid bit set on, enter:

# nohup find / -xdev -type f -perm +u=s -print > out.txt &

Type exit or press CTRL + D exit from remote server.

# exit

Please note that nohup does not change the scheduling priority of COMMAND; use nice for that:

# nohup nice -n -5 ls / > out.txt &

As you can see nohup keep processes running after you exit from a shell. Read man page of nohup and nice command for more information. Please note that nohup is almost available on Solaris/BSD/Linux/UNIX variant.

Update:
# 1: As pointed out by Jason you can use at command to queue a job for later execution. For example, you can run pullftp.sh script to queue (one minute) later execution

$ echo "pullftp.sh" | at now + 1 minute

# 2: You can also use screen command for same. Brock pointed out disown shell internal command for same purpose. Here is how you can try it out:

$ pullftp.sh & $ disown -h $ exit

Source : http://www.cyberciti.biz/tips/nohup-execute-commands-after-you-exit-from-a-shell-prompt.html