LAMP on CentOS 7

Posted on , Updated on , by Joel Kruger .

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LAMP on CentOS 7

A LAMP stack is a particular bundle of software packages commonly used for hosting web content. The bundle consists of Linux, Apache, MariaDB, and PHP. This guide shows you how to install a LAMP stack on a CentOS 7 Linode.

Before You Begin

  1. Ensure that you have followed the Getting Started and Securing Your Server guides. Ensure that the Linode’s hostname is set.

    Check your Linode’s hostname. The first command should show your short hostname and the second should show your fully qualified domain name (FQDN).

    hostname
    hostname -f
    
  2. Update your system:

    sudo yum update
    
    Note
    This guide is written for a non-root user. Commands that require elevated privileges are prefixed with sudo. If you’re not familiar with the sudo command, you can check our Users and Groups guide.

Apache

Install and Configure

  1. Install Apache 2.4:

    sudo yum install httpd
    
  2. Enable Apache to start at boot and start the Apache service:

     sudo systemctl enable httpd.service
     sudo systemctl start httpd.service
    
  3. Create a httpd-mpm.conf file and add the code in the example to turn off KeepAlive and adjust the resource use settings. The settings shown below are a good starting point for a Linode 2GB:

    Note

    As a best practice, you should create a backup of your Apache configuration file, before making any configuration changes to your Apache installation. To make a backup in your home directory:

    cp /etc/httpd/conf/httpd.conf ~/httpd.conf.backup
    
    File: /etc/httpd/conf.modules.d/httpd-mpm.conf
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    KeepAlive Off
    
    <IfModule prefork.c>
        StartServers        4
        MinSpareServers     20
        MaxSpareServers     40
        MaxClients          200
        MaxRequestsPerChild 4500
    </IfModule>

Configure Name-based Virtual Hosts

There are different ways to set up virtual hosts; however, the method below is recommended.

  1. Create the directories to store your site files and logs. Replace example.com with your own site’s domain name.

    sudo mkdir -p /var/www/html/example.com/{public_html,logs}
    
  2. Create the directories to store your site’s virtual hosts files:

     sudo mkdir -p /etc/httpd/sites-available /etc/httpd/sites-enabled
    
  3. Edit Apache’s configuration file to let it know to look for virtual host files in the /etc/httpd/sites-enabled directory. Add the example line to the bottom of your httpd.conf file:

    File: /etc/httpd/conf/httpd.conf
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    IncludeOptional sites-enabled/*.conf
          
  4. Navigate to your /var/www/html/example.com directory if you are not already there:

     cd /var/www/html/example.com
    
  5. Using your preferred text editor create a virtual hosts file. Copy the basic settings in the example below and paste them into the file. Replace all instances of example.com with your domain name:

    File: /etc/httpd/sites-available/example.com.conf
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    <Directory /var/www/html/example.com/public_html>
        Require all granted
    </Directory>
    <VirtualHost *:80>
        ServerName example.com
        ServerAdmin [email protected]
        DocumentRoot /var/www/html/example.com/public_html
        ErrorLog /var/www/html/example.com/logs/error.log
        CustomLog /var/www/html/example.com/logs/access.log combined
    </VirtualHost>
        
  6. Create a symbolic link from your virtual hosts file in the sites-available directory to the sites-enabled directory. Replace example.com.conf with the name of your own virtual hosts file.

     sudo ln -s /etc/httpd/sites-available/example.com.conf /etc/httpd/sites-enabled/example.com.conf
    
  7. Reload to apply your new configuration:

    sudo systemctl reload httpd.service
    
    Note
    If you receive an error when trying to reload your httpd service, follow the steps in the Configure SELinux to Allow HTTP section and then reattempt to reload the service.

    Additional domains can be added to the example.com.conf file as needed.

    Note
    ErrorLog and CustomLog entries are suggested for more fine-grained logging, but are not required. If they are defined (as shown above), the logs directories must be created before you restart Apache.

Configure SELinux to Allow HTTP

SELinux is enabled by default on CentOS 7 Linodes. Its default setting is to restrict Apache’s access to directories until explicit permissions are granted.

Without these steps, Apache will not start and may give the following error:

  Jun 21 17:58:09 example.com systemd[1]: Failed to start The Apache HTTP Server.
Jun 21 17:58:09 example.com systemd[1]: Unit httpd.service entered failed state.
Jun 21 17:58:09 example.com systemd[1]: httpd.service failed.
  1. Use chown to make apache the owner of the web directory:

    sudo chown apache:apache -R /var/www/html/example.com/
    
  2. Modify the permissions for files and directories:

    cd /var/www/html/example.com/
    find . -type f -exec sudo chmod 0644 {} \;
    find . -type d -exec sudo chmod 0755 {} \;
    
  3. Use SELinux’s chcon to change the file security context for web content:

    sudo chcon -t httpd_sys_content_t /var/www/html/example.com -R
    sudo chcon -t httpd_sys_rw_content_t /var/www/html/example.com -R
    
  4. Enable Apache to start at boot, and restart the service for the above changes to take place:

    sudo systemctl enable httpd.service
    sudo systemctl restart httpd.service
    

Configure FirewallD to Allow HTTP Connections

FirewallD is enabled for CentOS 7 Linodes, but HTTP is not included in the default set of services.

  1. View the default set of services:

     sudo firewall-cmd --zone=public --list-services
    
  ssh dhcpv6-client
  1. To allow connections to Apache, add HTTP as a service:

     sudo firewall-cmd --zone=public --add-service=http --permanent
     sudo firewall-cmd --zone=public --add-service=http
    

    Visit your domain or public IP to test the Apache server and view the default Apache page.

    Note

    Rename Apache’s default welcome page. When this file is present it will take precedence over other configurations via the LocationMatch directive.

    sudo mv /etc/httpd/conf.d/welcome.conf /etc/httpd/conf.d/welcome.conf.bk
    

MariaDB

Install and Configure

MariaDB is a relational database management system (RDBMS) and is a popular component of many applications.

  1. Install the MariaDB-server package:

    sudo yum install mariadb-server
    
  2. Set MariaDB to start at boot and start the daemon for the first time:

    sudo systemctl enable mariadb.service
    sudo systemctl start mariadb.service
    
  3. Run mysql_secure_installation to secure MariaDB. You will be given the option to change the MariaDB root password, remove anonymous user accounts, disable root logins outside of localhost, and remove test databases and reload privileges. It is recommended that you answer yes to these options:

    sudo mysql_secure_installation
    

Create a MariaDB Database

  1. Log in to MariaDB:

    mysql -u root -p
    

    Enter MariaDB’s root password. You will get the MariaDB prompt.

  2. Create a new database and user with permissions to use it:

    create database webdata;
    grant all on webdata.* to 'webuser' identified by 'password';
    

    In the above example webdata is the name of the database, webuser the user, and password a strong password.

  3. Exit MariaDB

    quit
    

With Apache and MariaDB installed, you are now ready to move on to installing PHP to provide scripting support for your web pages.

PHP

Install and Configure

  1. Install PHP:

    sudo yum install php php-pear php-mysqlnd
    
  2. Edit /etc/php.ini for better error messages and logs, and upgraded performance. These modifications provide a good starting point for a Linode 2GB:

    File: /etc/php.ini
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    error_reporting = E_COMPILE_ERROR|E_RECOVERABLE_ERROR|E_ERROR|E_CORE_ERROR
    error_log = /var/log/php/error.log
    max_input_time = 30
    Note
    Ensure that all lines noted above are uncommented. A commented line begins with a semicolon (;).
  3. Create the log directory for PHP and give the Apache user ownership:

    sudo mkdir /var/log/php
    sudo chown apache:apache /var/log/php
    
  4. Reload Apache:

    sudo systemctl reload httpd.service
    

Optional: Test and Troubleshoot the LAMP Stack

In this section, you’ll create a test page that shows whether Apache can render PHP and connect to the MariaDB database. This can be helpful in locating the source of an error if one of the elements of your LAMP stack is not communicating with the others.

  1. Paste the following code into a new file, phptest.php, in the public_html directory. Modify webuser and password to match the information entered in the Create a MariaDB Database section above:

    File: /var/www/html/example.com/public_html/phptest.php
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    <html>
    <head>
    <title>PHP Test</title>
    </head>
        <body>
        <?php echo '<p>Hello World</p>';
    
        // In the variables section below, replace user and password with your own MariaDB credentials as created on your server
        $servername = "localhost";
        $username = "webuser";
        $password = "password";
    
        // Create MariaDB connection
        $conn = mysqli_connect($servername, $username, $password);
    
        // Check connection - if it fails, output will include the error message
        if (!$conn) {
        die('<p>Connection failed: </p>' . mysqli_connect_error());
        }
        echo '<p>Connected successfully</p>';
        ?>
        </body>
    </html>
    
        
    
  2. Navigate to example.com/phptest.php from your local machine. If the components of your LAMP stack are working correctly, the browser will display a “Connected successfully” message. If not, the output will be an error message.

  3. Remove the test file:

    sudo rm /var/www/html/example.com/public_html/phptest.php
    

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