You can install Apache through APT or build it yourself from source code. The Apache source builds on just about any UNIX-like operating system and on Win32. If you are about to install a new version of Apache, you should shut down the old server. Even if it's unlikely that the old server will interfere with the installation procedure, shutting it down ensures that there will be no problems. If you do not know how to stop Apache, see the "Starting and Stopping Apache" section later in this chapter. Installing with APTYou can find the Apache package on the Ubuntu installation media, on the Ubuntu FTP server, or at one of its many mirror sites. Updated packages usually contain important bug and security fixes. When an updated version is released, install it as quickly as possible to keep your system secure. Note Check the Apache site for security reports. Browse to http://httpd.apache.org/ security_report.html for links to security vulnerabilities for Apache 1.3, 2.0, and 2.2. Subscribe to a support list or browse through up-to-date archives of all Apache mailing lists at http://httpd.apache.org/mail/ (for various articles) or http://httpd.apache.org/lists.html (for comprehensive and organized archives). Caution You should be wary of installing experimental packages, and never install them on production servers (that is, servers used in "real life"). Very carefully test the packages beforehand on a host that is not connected to a network! The easiest way to use APT is through Synaptic, which is under the System > Administration menu. Search for apache2 and select it, and Synaptic will add the required dependencies. Alternatively you can install Apache through a .deb package with the command-line dpkg tool by typing the following: dpkg -i latest_apache.deb where latest_apache.deb is the name of the latest Apache package. For more information on installing packages with APT and dpkg, refer to Chapter 7, "Managing Software." The Apache package installs files in the following directories:
When Apache is being run, it also creates the file apache2.pid, containing the process ID of Apache's parent process in the /var/run/ directory. Note If you are upgrading to a newer version of Apache, APT does not write over your current configuration files. Building the Source YourselfYou can download the source directly from http://www.apache.org/. The latest version at the time of this writing (2.2.0) is a 6MB compressed tape archive, and the latest pre-2.0 version of Apache is 1.3.34. Although many sites continue to use the older version (for script and other compatibility reasons), many new sites are migrating to or starting out using the latest stable version. After you have the tar file, you must unroll it in a temporary directory, such as /tmp. Unrolling this tar file creates a directory called apache_version_number, where version_number is the version you have downloaded (for example, apache_1.3.34). There are two ways to compile the sourcethe old, familiar way (at least, to those of us who have been using Apache for many years) by editing Makefile templates, and the new, easy way using a configure script. You will first see how to build Apache from source the easy way. The configure script offers a way to have the source software automatically configured according to your system. However, manually editing the configuration files before building and installing Apache provides more control over where the software is installed and which capabilities or features are built in to Apache. Tip As with many software packages distributed in source code form for Linux and other UNIX-like operating systems, extracting the source code results in a directory that contains a README and an INSTALL file. Be sure to peruse the INSTALL file before attempting to build and install the software. Using ./configure to Build ApacheTo build Apache the easy way, run the ./configure script in the directory just created. You can provide it with a --prefix argument to install it in a directory other than the default, which is /usr/local/apache/. Use this command: # ./configure --prefix=/preferred/directory/ This generates the Makefile that is used to compile the server code. Next, type make to compile the server code. After the compilation is complete, type make install as root to install the server. You can now configure the server via the configuration files. See the "Runtime Server Configuration Settings" section for more information. Tip A safer way to install a new version of Apache from source is to use the ln command to create symbolic links of the existing file locations (listed in the "Installing with APT" section earlier in this chapter) to the new locations of the files. This method is safer because the default install locations are different from those used when the package installs the files. Failure to use this installation method could result in your web server process not being started automatically at system startup. Another safe way to install a new version of Apache is to first back up any important configuration directories and files (such as /etc/httpd) and then use the apt-get command to remove the server. You can then install and test your new version and, if needed, easily restore your original server and settings. It is strongly recommended that you use Ubuntu's version of Apache until you really know what happens at system startup. No "uninstall" option is available when installing Apache from source! Apache File Locations After a Build and InstallFiles are placed in various subdirectories of /usr/local/apache (or whatever directory you specified with the --prefix parameter) if you build the server from source. Before version 1.3.4, files were placed in /usr/local/etc/httpd. The following is a list of the directories used by Apache, as well as brief comments on their usage:
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