Starting and Stopping Apache


At this point, you have installed your Apache server with its default configuration. Ubuntu provides a default home page named index.html as a test under the /var/www/ directory. The proper way to run Apache is to set system initialization to have the server run after booting, network configuration, and any firewall configuration. See Chapter 15, "Automating Tasks," for more information about how Ubuntu boots.

It is time to start it up for the first time. The following sections show how to either start and stop Apache or configure Ubuntu to start or not start Apache when booting.

Starting the Apache Server Manually

You can start Apache from the command line of a text-based console or X terminal window, and you must have root permission to do so. The server daemon, apache2, recognizes several command-line options you can use to set some defaults, such as specifying where apache2 reads its configuration directives. The Apache apache2 executable also understands other options that enable you to selectively use parts of its configuration file, specify a different location of the actual server and supporting files, use a different configuration file (perhaps for testing), and save startup errors to a specific log. The -v option causes Apache to print its development version and quit. The -V option shows all the settings that were in effect when the server was compiled.

The -h option prints the following usage information for the server (assuming that you are running the command through sudo):

sudo httpd -h Usage: httpd [-D name] [-d directory] [-f file]              [-C "directive"] [-c "directive"]              [-k start|restart|graceful|stop]              [-v] [-V] [-h] [-l] [-L] [-t] Options:   -D name           : define a name for use in <IfDefine name> directives   -d directory      : specify an alternate initial ServerRoot   -f file           : specify an alternate ServerConfigFile   -C "directive"    : process directive before reading config files   -c "directive"    : process directive after reading config files   -e level          : show startup errors of level (see LogLevel)   -E file           : log startup errors to file   -v                : show version number   -V                : show compile settings   -h                : list available command line options (this page)   -l                : list compiled in modules   -L                : list available configuration directives   -t -D DUMP_VHOSTS : show parsed settings (currently only vhost settings) -t                : run syntax check for config files 


Other options include listing Apache's static modules, or special, built-in independent parts of the server, along with options that can be used with the modules. These options are called configuration directives and are commands that control how a static module works. Note that Apache also includes nearly 50 dynamic modules, or software portions of the server that can be optionally loaded and used while the server is running.

The -t option is used to check your configuration files. It's a good idea to run this check before restarting your server, especially if you've made changes to your configuration files. Such tests are important because a configuration file error can result in your server shutting down when you try to restart it.

Note

When you build and install Apache from source, start the server manually from the command line through sudo (such as when testing). You do this for two reasons:

  • The standalone server uses the default HTTP port (port 80), and only the superuser can bind to Internet ports that are lower than 1024.

  • Only processes owned by root can change their UID and GID as specified by Apache's User and Group directives. If you start the server under another UID, it runs with the permissions of the user starting the process.

Note that although some of the following examples show how to start the server through sudo, you should do so only for testing after building and installing Apache.


Using /etc/init.d/apache2

Ubuntu uses the scripts in the /etc/init.d directory to control the startup and shutdown of various services, including the Apache web server. The main script installed for the Apache web server is /etc/init.d/apache2, although the actual work is done by the apache2ctl shell script included with Apache.

Note

/etc/init.d/apache2 is a shell script and is not the same as the Apache server located in /usr/sbin. That is, /usr/sbin/apache2 is the program executable file (the server); /etc/init.d/apache2 is a shell script that uses another shell script, apache2ctl, to control the server. See Chapter 15 for a description of some service scripts under /etc/init.d and how the scripts are used to manage services such as apache2.


You can use the /etc/init.d/apache2 script and the following options to control the web server:

  • start The system uses this option to start the web server during bootup. You, through sudo, can also use this script to start the server.

  • stop The system uses this option to stop the server gracefully. You should use this script, rather than the kill command, to stop the server.

  • reload You can use this option to send the HUP signal to the apache2 server to have it reread the configuration files after modification.

  • restart This option is a convenient way to stop and then immediately start the web server. If the apache2 server isn't running, it is started.

  • condrestart The same as the restart parameter, except that it restarts the apache2 server only if it is actually running.

  • status This option indicates whether the server is running; if it is, it provides the various PIDs for each instance of the server.

For example, to check on the status of your server, use the command

sudo /etc/init.d/apache2 status 


This prints the following for me:

apache2 (pid 15997 1791 1790 1789 1788 1787 1786 1785 1784 1781) is running... 


This indicates that the web server is running; in fact, 10 instances of the server are currently running in this configuration.

In addition to the previous options, the apache2 script also offers these features:

  • help Prints a list of valid options to the apache2 script (which are passed onto the server as if called from the command line).

  • configtest A simple test of the server's configuration, which reports Status OK if the setup is correct. You can also use apache2's -t option to perform the same test, like this:

    audo apache2 -t 

  • fullstatus Displays a verbose status report.

  • graceful The same as the restart parameter, except that the configtest option is used first and open connections are not aborted.

Tip

Use the reload option if you are making many changes to the various server configuration files. This saves time when you are stopping and starting the server by having the system simply reread the configuration files.




Ubuntu Unleashed
Ubuntu Unleashed 2011 Edition: Covering 10.10 and 11.04 (6th Edition)
ISBN: 0672333449
EAN: 2147483647
Year: 2006
Pages: 318

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