Apache: Difference between revisions

Latest revision as of 09:15, 8 December 2011

This article refers to the 'Apache HTTP server'

The Apache HTTP server is the software that (along with the PHP scripting language) 'runs' Moodle. Note that there are alternatives (e.g. IIS on Windows) but the Apache HTTP Server is very popular on all platforms.

Installing Apache

Installers are available for most platforms from http://httpd.apache.org/download.cgi. The official installation instructions are here: http://httpd.apache.org/docs/2.0/install.html. If you are running Linux then you are recommended to use the packaged version if you can. For example in Debian/Ubuntu it is simply:

sudo apt-get install apache2

See the documentation for your particular platform for the instructions. Apache is straightforward to build from source if you have to and the PHP documentation contains an article on building both Apache and PHP together - although you should rarely need to do that.

Performance

See Performance recommendations

SSL

Moodle has an option to enable login pages to force the HTTPS protocol. This is recommended but requires that your web server is configured for SSL. It is possible to run the whole site over HTTPS (typically by configuring Apache to rewrite all http:// URLs to https://) but as this disables caching, there is a considerable performance hit. Only do this if you have a very good reason.

WARNING: Before switching on login over HTTPS, make very sure that HTTPS is working (just change the http:// to https:// in any Moodle URL). If not, you may lock yourself out

You have two options for obtaining an SSL certificate:

generate a self-signed certificate. This is fine on (say) an Intranet but unsuitable for the public internet (except perhaps for testing). The user has no assurance that the certificate is legitimate.
purchase a certificate from a vendor. There is a surprising range of prices and value-added services available. Some hosting companies even provide free certificates.

Below are instructions for install of a self-signed certificate. If you purchase a certificate you will normally receive instructions for installing it

Debian and Apache2

1. generate a certification:

apache2-ssl-certificate

for debian etch, apache2-ssl-certificate is no longer available, use make-ssl-cert instead:

make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem

2. edit /etc/apache2/ports.conf:

      Listen 80
      Listen 443

3. copy /etc/apache)2/sites-available/default to /etc/apache2/sites-available/default-ssl, and change /etc/apache2/sites-available/default:

      NameVirtualHost *:80
      <VirtualHost *:80>
      ...
      </VirtualHost>

and also /etc/apache2/sites-available/default-ssl:

      NameVirtualHost *:443
      <VirtualHost *:443>
      ...
              SSLEngine on
              SSLCertificateFile /etc/apache2/ssl/apache.pem
      ...
      </VirtualHost>

4. symbolic link the ssl file:

a2ensite default-ssl

5. don't forget to symbolic link the ssl module:

a2enmod ssl

6. restart apache and test the connection (e.g. https://localhost/):

/etc/init.d/apache2 restart

@@ Line 1: / Line 1: @@
-When most people refer to '''Apache''' they are talking about the "Apache HTTP Server Project". In fact Apache is really the "Apache Software Foundation" which hosts a long list of projects of which the HTTP server is just one, albeit the best known.
+{{Installing Moodle}}
+'''This article refers to the 'Apache HTTP server''''
-The Apache HTTP Server enables web pages to be published on the internet (or an intranet or even on a single test machine). The [[PHP]] scripting language, in which Moodle is developed, is tightly integrated with the Apache HTTP Server. A web server is a required component of a Moodle installation. There are two distinct developments of the Apache HTTP Server, version 1 and version 2. Although version 2 should have replaced version 1, the architectures are so different that they both continue to be supported. Either are fully supported by PHP and Moodle.
+The Apache HTTP server is the software that (along with the PHP scripting language) 'runs' Moodle. Note that there are alternatives (e.g. IIS on Windows) but the Apache HTTP Server is very popular on all platforms.
-The Apache HTTP Server Project describes itself thus:
-"The Apache HTTP Server Project is an effort to develop and maintain an open-source HTTP server for modern operating systems including UNIX and Windows NT. The goal of this project is to provide a secure, efficient and extensible server that provides HTTP services in sync with the current HTTP standards.
-Apache has been the most popular web server on the Internet since April 1996. The November 2005 Netcraft Web Server Survey found that more than 70% of the web sites on the Internet are using Apache, thus making it more widely used than all other web servers combined."
 == Installing Apache ==
-Usually Apache is installed alongside PHP and [[MySQL]] in a combination known as XAMPP or MAMP. See information about [[Complete install packages for Windows|XAMPP(Windows cross platforms)]] and for information about [[Complete Install Packages for Mac OS X|MAMP (Mac OS platforms)]].
+Installers are available for most platforms from http://httpd.apache.org/download.cgi. The official installation instructions are here: http://httpd.apache.org/docs/2.0/install.html. If you are running Linux then you are recommended to use the packaged version if you can. For example in Debian/Ubuntu it is simply:
+<pre>
+sudo apt-get install apache2
+</pre>
-Debian/Ubuntu:
+See the documentation for your particular platform for the instructions. Apache is straightforward to build from source if you have to and the PHP documentation contains an article on building both Apache and PHP together - although you should rarely need to do that.
- apt-get install apache2
 ==Performance==
-'''Caching'''
+See [[Performance recommendations]]
-Apache can be tuned to make pages load faster by specifying how the browser should cache the various page elements. How to do this varies slightly between OSes but there are two basic steps
+==SSL==
-# Install and enable mod_expires - refer to documentation or man pages
-# Add this code to the virtual server config file within the section for the root directory (or within the .htaccess file if AllowOverrides is On):
- <IfModule mod_expires.c>
-  ExpiresActive On
-  ExpiresDefault "access plus 1 seconds"
-  ExpiresByType text/html "access plus 1 seconds"
-  ExpiresByType image/gif "access plus 120 minutes"
-  ExpiresByType image/jpeg "access plus 120 minutes"
-  ExpiresByType image/png "access plus 120 minutes"
-  ExpiresByType text/css "access plus 60 minutes"
-  ExpiresByType text/javascript "access plus 60 minutes"
-  ExpiresByType application/x-javascript "access plus 60 minutes"
-  ExpiresByType text/xml "access plus 1 seconds"
- </IfModule>
-The effect is to make everything stay in the cache except HTML and XML, which change dynamically. It's possible to gain a several hundred percent decrease in load times this way
-More info: [http://www.metaskills.net/blog/heuristics/sysadmin/how-to-control-browser-caching-with-apache-2 www.metaskills.net]
-'''Servers'''
-Apache serves webpages by spawning new child processes (smaller sub-programs) to deal with each connection. The number of these that you allow to run and to be kept in reserve has a big impact on how fast your server will run. The risk (especially on a server with a small amount of memory, such as a VPS) is that the available RAM will run out and the system will end up using the far slower hard disk as swap memory instead. To prevent this, you need to tell Apache only to have a certain number. Here is a sample set of configuration directives for a VPS server with 128MB of RAM (with up to 384 burstable), which apparently works quite well (more info [http://www.agnivo.com/tech/vps-mysql-and-apache-optimization-guide-27.html here])
-Make a back up of your httpd.conf first. It’s generally found at /etc/httpd/conf/httpd.conf, then open the file with your editor e.g.
- nano /etc/httpd/conf/httpd.conf
-Then look for these values, which may be spread about a little and change them:
+Moodle has an option to enable login pages to force the HTTPS protocol. This is recommended but requires that your web server is configured for SSL. It is possible to run the whole site over HTTPS (typically by configuring Apache to rewrite all http:// URLs to <nowiki>https://</nowiki>) but as this disables caching, there is a considerable performance hit. Only do this if you have a very good reason.
- Timeout 200
+'''WARNING: Before switching on login over HTTPS, make very sure that HTTPS is working (just change the http:// to https:// in any Moodle URL). If not, you may lock yourself out'''
- KeepAlive On
- MaxKeepAliveRequests 200
- KeepAliveTimeout 3
- MinSpareServers 5
- MaxSpareServers 15
- StartServers 5
- MaxClients 20
- MaxRequestsPerChild 2000
- HostnameLookups Off
-If you find that you are running out of memory (type
+You have two options for obtaining an SSL certificate:
+* generate a self-signed certificate. This is fine on (say) an Intranet but unsuitable for the public internet (except perhaps for testing). The user has no assurance that the certificate is legitimate.
- top
+* purchase a certificate from a vendor. There is a surprising range of prices and value-added services available. Some hosting companies even provide free certificates.
-if using Linux and look at the swap figure), just lower some of the numbers. Similary, if you have extra memory, you can afford to raise them a bit. Remember to combine tuning of Apache with tuning of your database app.
-==SSL==
-If you want your website not to be hackable, you need to enable SSL so that your moodle password cannot be easily read by others as it is transmitted (as normal internet communications normally can be). There are 2 options - generate a self-signed certificate, which stops casual network sniffing, but which can ultimately be compromised with enough effort, or purchase a certificate from a vendor (about $35 per year from the cheap ones). Below are instructions for install of a self-signed certificate.
+Below are instructions for install of a self-signed certificate. If you purchase a certificate you will normally receive instructions for installing it
-'''Debian and Apache2'''
+===Debian and Apache2===
 . generate a certification:
-      apache2-ssl-certificate
+<pre>
+apache2-ssl-certificate
+</pre>
 for debian etch, apache2-ssl-certificate is no longer available, use make-ssl-cert instead:
-          make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem
+<pre>
+make-ssl-cert /usr/share/ssl-cert/ssleay.cnf /etc/apache2/ssl/apache.pem
+</pre>
 . edit /etc/apache2/ports.conf:
+<pre>
        Listen 80
        Listen 443
-. copy /etc/apache2/sites-available/default to /etc/apache2/sites-available/default-ssl, and change /etc/apache2/sites-available/default:
+</pre>
+. copy /etc/apache)2/sites-available/default to /etc/apache2/sites-available/default-ssl, and change /etc/apache2/sites-available/default:
+<pre>
        NameVirtualHost *:80
        <VirtualHost *:80>
        ...
        </VirtualHost>
+</pre>
 and also /etc/apache2/sites-available/default-ssl:
+<pre>
        NameVirtualHost *:443
        <VirtualHost *:443>
@@ Line 96: / Line 60: @@
        ...
        </VirtualHost>
+</pre>
 . symbolic link the ssl file:
-      a2ensite default-ssl
+<pre>
+a2ensite default-ssl
+</pre>
 . don't forget to symbolic link the ssl module:
-      a2enmod ssl
+<pre>
-. restart apache and test the connection (e.g. https://localhost/):
+a2enmod ssl
-      /etc/init.d/apache2 restart
+</pre>
+. restart apache and '''test the connection''' (e.g. https://localhost/):
+<pre>
+/etc/init.d/apache2 restart
+</pre>
 == See also ==
@@ Line 109: / Line 80: @@
 * [http://httpd.apache.org/docs/2.0/misc/perf-tuning.html Apache Performance Tuning article at the official homepage]
 * [https://els.earlham.edu/cayaraa/weblog/1468.html Making Moodle work with SSL]
+* [http://www.krufix.de/ Using the same Moodle twice in local network and Internet via SSL-Proxy] (in German)
-[[Category:Administrator]]
-[[Category:Developer]]
 [[pl:Apache]]
 [[ja:Apache]]
+[[de:Apache]]

Documentation

Apache: Difference between revisions

Latest revision as of 09:15, 8 December 2011

Contents

Installing Apache

Performance

SSL

Debian and Apache2

See also