Transcript Linux Operations and Administration

Linux Operations and
Administration
Chapter Ten
Apache Web Server
Objectives
• Install Apache Web Server along with additional
Apache modules
• Configure an Apache Web server with a GUI utility
and by modifying Apache configuration files
• Create a Web page by writing an HTML script
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Installing Apache Web Server
• Web server
– A network computer with the primary role of serving
Web pages to clients on request
– Can also host a Web site along with images, style
sheets, and other content
• Clients (Web browsers) can access the Web pages
– Receives data from clients
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Installing Apache Web Server (cont’d.)
• Apache Web Server
–
–
–
–
Open-source
Free
Developed by Apache Software Foundation (ASF)
Designed to run on a wide variety of operating
systems
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Installing Apache Web Server (cont’d.)
• Apache version 2.2
– Included with openSUSE
– Not installed by default
– Configured to run “out of the box” with no further
modifications needed
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Installing Apache Web Server (cont’d.)
• Apache software is mostly modular
• PHP module
– A poplar module
– PHP
• A server-side scripting language
• Commonly used to create dynamic Web pages
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Installing Apache Web Server (cont’d.)
• Options to install Apache Web Server
– yast command
– YaST Software Management module
• Activity 10-1: Installing Apache Web Server
– Install Apache Web Server and other Web-related
packages
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Starting and Stopping Apache
• To start apache2 service using YaST:
– Open YaST
– Select System Services (Runlevel)
– Search for apache2 and enable the service
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Starting and Stopping Apache (cont’d.)
• To start apache2 service at the command line:
– rcapache2 command
• Can be used only by the root user
• Is a link to a startup script in /etc/init.d directory
• Used to start, stop, and restart apache2 service
• Table 10-1
– Describes common options used with rcapache2
command
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Starting and Stopping Apache (cont’d.)
Table 10-1 Common options used with rcapache2
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Starting and Stopping Apache (cont’d.)
• To test an Apache Web server:
– Start Firefox
– Enter http://localhost in address bar
• Activity 10-2: Starting and Testing an ApacheWeb
Server
– Check the status of an Apache Web server, stop and
start the apache2 service, and test an ApacheWeb
server at the command line and with a GUI tool
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Starting and Stopping Apache (cont’d.)
Figure 10-1 The Apache test page
© Cengage Learning 2013
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Configuring Apache Web Server
• Methods to configure Apache Web server
– Use the graphical YaST module (yast2-httpserver)
• Advantages: convenient and easy to use
– Modify Apache configuration files
• httpd.conf
– Main configuration file
– Contains directives (instructions that tell Apache
how to run)
• Advantage: can make more detailed changes
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Apache Configuration with HTTPServer
• HTTP-Server
– A YaST module for configuring Apache
– Package name: yast2-http-server
– Can be installed from YaST Software Management
• To begin the Apache configuration process in
HTTP-Server:
– Use yast2 http-server command
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Apache Configuration with HTTPServer (cont’d.)
Figure 10-2 The HTTP Server Wizard
© Cengage Learning 2013
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Apache Configuration with HTTPServer (cont’d.)
• HTTP Server Wizard
– Five steps
– Can choose network interface and ports that Apache
listens on
• Port
– An interface for connecting a hardware device,
such as a disk drive or printer
– In networking, it’s a data connection established
for communication between hosts
– Port number identifies the type of function
assigned to it
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Apache Configuration with HTTPServer (cont’d.)
• HTTP Server Wizard allows you to enable scripting
languages
– Such as PHP and Perl
• Web server’s default host
– First declared virtual host in the configuration file
• Virtual host
– Makes it possible to run multiple domains on one
physical machine
• You can add virtual hosts as needed with HTTP
Server Wizard
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Apache Configuration with HTTPServer (cont’d.)
Figure 10-3 Configuring the
default host
© Cengage Learning 2013
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Apache Configuration with HTTPServer (cont’d.)
• You can set the following for a Web server in
Apache:
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DocumentRoot
Alias
ScriptAlias
Include
Server Name
Server Administrator E-Mail
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Apache Configuration with HTTPServer (cont’d.)
• Activity 10-3: Using the HTTP Server Wizard
– Configure an Apache Web server with the HTTP
Server Wizard
• Expert mode
– Enables you to adjust more settings than in the
wizard
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Apache Configuration with HTTPServer (cont’d.)
Figure 10-4 Expert mode in the
HTTP Server Wizard
© Cengage Learning 2013
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Manual Apache Configuration
• Can configure an Apache Web server manually
– Edit configuration files in /etc/apache2/ directory
• Table 10-2
– Describes common configuration files stored in this
directory
• Apache configuration files follow the syntax:
– One directive per line
– # symbols indicate comments
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Manual Apache Configuration (cont’d.)
Table 10-2 Apache configuration files
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Manual Apache Configuration (cont’d.)
• apache2ctl -t command
– Verifies that configuration files have no syntax errors
• Activity 10-4: Using Apache Configuration Files
– Explore common Apache configuration files
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Manual Apache Configuration (cont’d.)
Figure 10-5 Contents of an Apache configuration file
© Cengage Learning 2013
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Virtual Hosts
• Virtual hosts can be used to support multiple Web
sites on one physical server
• By default, Apache is configured with a default host
and no virtual host
• Apache supports:
– Name-based virtual hosts
• Multiple Web sites share the same IP address
– IP-based virtual hosts
• Multiple IP addresses for a single machine
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Name-Based Virtual Hosts
• Ways to create name-based virtual hosts:
– Editing httpd.conf file
– Virtual host configuration files
• NameVirtualHost directive
– Specifies the IP address to use for name-based
virtual hosts
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Name-Based Virtual Hosts (cont’d.)
• An httpd.conf file that has been modified to
support two virtual hosts:
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Name-Based Virtual Hosts (cont’d.)
• ServerName directive
– Specifies name of the server
– Apache uses it to determine which virtual host is
displayed
• All virtual hosts you create must have their server
name resolved on the network
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Name-Based Virtual Hosts (cont’d.)
• ServerAlias directive
– Can be used to define multiple names for a virtual
host
• Order, Allow, and Deny directives
– Enable you to define which hosts can access files in
a particular directory and which hosts can’t
– Order directive
• Tells Apache which filter (allow or deny) should be run
first
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Name-Based Virtual Hosts (cont’d.)
• Another way to create virtual hosts is to create a
virtual host configuration file in
/etc/apache2/vhosts.d directory
• Virtual host template (vhost.template)
– You can copy it and rename
• A virtual host configuration file must have a .conf
extension
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Name-Based Virtual Hosts (cont’d.)
• ServerAdmin directive
– Lists the Apache administrator’s e-mail account
• The only directives you must change:
– ServerName directive
– DocumentRoot directive
• Defines the directory path Apache uses to serve files
for this host
– Directory directive
• Applies only to the named file system directory and
subdirectories and their contents
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Name-Based Virtual Hosts (cont’d.)
• After creating a virtual host configuration file, define
NameVirtualHost directive in
/etc/apache2/listen.conf file
• Activity 10-5: Creating Virtual Hosts
– Use a template to create virtual Apache Web servers
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Name-Based Virtual Hosts (cont’d.)
Figure 10-7 Defining the NameVirtualHost directive in the listen.conf file
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Creating a Web Page
• DocumentRoot directive
– Defines the directory Apache uses to serve Web
pages to clients
• Uniform Resource Locator (URL)
– An address to a resource on the Internet
• index.html file
– Main Web page
– Default content in HTML markup:
<html><body><h1>It works!</h1></body></html>
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Creating a Web Page (cont’d.)
Figure 10-8 A URL requesting a directory
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Creating a Web Page (cont’d.)
• Hypertext Markup Language (HTML)
– Hypertext
• Contains references or links to access other files or
text
– Markup language
• Consists of instructions called tags that define how
text is displayed
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Creating a Web Page (cont’d.)
Figure 10-9 Placing HTML tags on separate lines
© Cengage Learning 2013
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Creating a Web Page (cont’d.)
Table 10-3 Common HTML tags
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Creating a Web Page (cont’d.)
• To create a Web page in openSUSE Linux:
– You must use a text editor
• Activity 10-6: Creating Web Pages with HTML
– Create a basic HTML Web page
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Summary
• Apache Web Server
– Web server software that can be downloaded free
– Available with the latest version of openSUSE
• rcapache2 command can be used to:
– Check status of Apache Web server
– Start, stop, and restart the server
• HTTP-Server is a YaST application module for
configuring Apache
• Manual Apache configuration: modifying directives
(instructions) in Apache configuration files
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Summary (cont’d.)
• With virtual hosts in Apache Web Server, you can
run multiple Web sites on one physical machine
• Apache Web Server supports two types of virtual
hosts:
– Name-based virtual hosts
– IP-based virtual hosts
• A number of directives can be configured on an
Apache Web server
– Includes the mandatory DocumentRoot, Directory,
and ServerName
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