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diff --git a/APACHE_1_3_42/htdocs/manual/vhosts/mass.html b/APACHE_1_3_42/htdocs/manual/vhosts/mass.html new file mode 100644 index 0000000000..eb46f3db6f --- /dev/null +++ b/APACHE_1_3_42/htdocs/manual/vhosts/mass.html @@ -0,0 +1,442 @@ +<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" + "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd"> + +<html xmlns="http://www.w3.org/1999/xhtml"> + <head> + <meta name="generator" content="HTML Tidy, see www.w3.org" /> + + <title>Dynamically configured mass virtual hosting</title> + </head> + <!-- Background white, links blue (unvisited), navy (visited), red (active) --> + + <body bgcolor="#FFFFFF" text="#000000" link="#0000FF" + vlink="#000080" alink="#FF0000"> + <!--#include virtual="header.html" --> + + <h1 align="CENTER">Dynamically configured mass virtual + hosting</h1> + + <p>This document describes how to efficiently serve an + arbitrary number of virtual hosts with Apache 1.3. <!-- + + Written by Tony Finch (fanf@demon.net) (dot@dotat.at). + + Some examples were derived from Ralf S. Engleschall's document + http://www.engelschall.com/pw/apache/rewriteguide/ + + Some suggestions were made by Brian Behlendorf. + + --> + </p> + + <h2><a id="contents" name="contents">Contents:</a></h2> + + <ul> + <li><a href="#motivation">Motivation</a></li> + + <li><a href="#overview">Overview</a></li> + + <li><a href="#simple">Simple dynamic virtual hosts</a></li> + + <li><a href="#homepages">A virtually hosted homepages + system</a></li> + + <li><a href="#combinations">Using more than one virtual + hosting system on the same server</a></li> + + <li><a href="#ipbased">More efficient IP-based virtual + hosting</a></li> + + <li><a href="#oldversion">Using older versions of + Apache</a></li> + + <li><a href="#simple.rewrite">Simple dynamic virtual hosts + using <code>mod_rewrite</code></a></li> + + <li><a href="#homepages.rewrite">A homepages system using + <code>mod_rewrite</code></a></li> + + <li><a href="#xtra-conf">Using a separate virtual host + configuration file</a></li> + </ul> + <hr /> + + <h2><a id="motivation" name="motivation">Motivation</a></h2> + + <p>The techniques described here are of interest if your + <code>httpd.conf</code> contains many + <code><VirtualHost></code> sections that are + substantially the same, for example:</p> +<pre> +NameVirtualHost 111.22.33.44 +<VirtualHost 111.22.33.44> + ServerName www.customer-1.com + DocumentRoot /www/hosts/www.customer-1.com/docs + ScriptAlias /cgi-bin/ /www/hosts/www.customer-1.com/cgi-bin +</VirtualHost> +<VirtualHost 111.22.33.44> + ServerName www.customer-2.com + DocumentRoot /www/hosts/www.customer-2.com/docs + ScriptAlias /cgi-bin/ /www/hosts/www.customer-2.com/cgi-bin +</VirtualHost> +# blah blah blah +<VirtualHost 111.22.33.44> + ServerName www.customer-N.com + DocumentRoot /www/hosts/www.customer-N.com/docs + ScriptAlias /cgi-bin/ /www/hosts/www.customer-N.com/cgi-bin +</VirtualHost> +</pre> + <br /> + <br /> + + + <p>The basic idea is to replace all of the static + <code><VirtualHost></code> configuration with a mechanism + that works it out dynamically. This has a number of + advantages:</p> + + <ol> + <li>Your configuration file is smaller so Apache starts + faster and uses less memory.</li> + + <li>Adding virtual hosts is simply a matter of creating the + appropriate directories in the filesystem and entries in the + DNS - you don't need to reconfigure or restart Apache.</li> + </ol> + <br /> + <br /> + + + <p>The main disadvantage is that you cannot have a different + log file for each virtual host; however if you have very many + virtual hosts then doing this is dubious anyway because it eats + file descriptors. It is better to log to a pipe or a fifo and + arrange for the process at the other end to distribute the logs + to the customers (it can also accumulate statistics, etc.).</p> + <hr /> + + <h2><a id="overview" name="overview">Overview</a></h2> + + <p>A virtual host is defined by two pieces of information: its + IP address, and the contents of the <code>Host:</code> header + in the HTTP request. The dynamic mass virtual hosting technique + is based on automatically inserting this information into the + pathname of the file that is used to satisfy the request. This + is done most easily using <a + href="../mod/mod_vhost_alias.html"><code>mod_vhost_alias</code></a>, + but if you are using a version of Apache up to 1.3.6 then you + must use <a + href="../mod/mod_rewrite.html"><code>mod_rewrite</code></a>. + Both of these modules are disabled by default; you must enable + one of them when configuring and building Apache if you want to + use this technique.</p> + + <p>A couple of things need to be `faked' to make the dynamic + virtual host look like a normal one. The most important is the + server name which is used by Apache to generate + self-referential URLs, etc. It is configured with the + <code>ServerName</code> directive, and it is available to CGIs + via the <code>SERVER_NAME</code> environment variable. The + actual value used at run time is controlled by the <a + href="../mod/core.html#usecanonicalname"><code>UseCanonicalName</code></a> + setting. With <code>UseCanonicalName Off</code> the server name + comes from the contents of the <code>Host:</code> header in the + request. With <code>UseCanonicalName DNS</code> it comes from a + reverse DNS lookup of the virtual host's IP address. The former + setting is used for name-based dynamic virtual hosting, and the + latter is used for IP-based hosting. If Apache cannot work out + the server name because there is no <code>Host:</code> header + or the DNS lookup fails then the value configured with + <code>ServerName</code> is used instead.</p> + + <p>The other thing to `fake' is the document root (configured + with <code>DocumentRoot</code> and available to CGIs via the + <code>DOCUMENT_ROOT</code> environment variable). In a normal + configuration this setting is used by the core module when + mapping URIs to filenames, but when the server is configured to + do dynamic virtual hosting that job is taken over by another + module (either <code>mod_vhost_alias</code> or + <code>mod_rewrite</code>) which has a different way of doing + the mapping. Neither of these modules is responsible for + setting the <code>DOCUMENT_ROOT</code> environment variable so + if any CGIs or SSI documents make use of it they will get a + misleading value.</p> + <hr /> + + <h2><a id="simple" name="simple">Simple dynamic virtual + hosts</a></h2> + + <p>This extract from <code>httpd.conf</code> implements the + virtual host arrangement outlined in the <a + href="#motivation">Motivation</a> section above, but in a + generic fashion using <code>mod_vhost_alias</code>.</p> +<pre> +# get the server name from the Host: header +UseCanonicalName Off + +# this log format can be split per-virtual-host based on the first field +LogFormat "%V %h %l %u %t \"%r\" %s %b" vcommon +CustomLog logs/access_log vcommon + +# include the server name in the filenames used to satisfy requests +VirtualDocumentRoot /www/hosts/%0/docs +VirtualScriptAlias /www/hosts/%0/cgi-bin +</pre> + + <p>This configuration can be changed into an IP-based virtual + hosting solution by just turning <code>UseCanonicalName + Off</code> into <code>UseCanonicalName DNS</code>. The server + name that is inserted into the filename is then derived from + the IP address of the virtual host.</p> + <hr /> + + <h2><a id="homepages" name="homepages">A virtually hosted + homepages system</a></h2> + + <p>This is an adjustment of the above system tailored for an + ISP's homepages server. Using a slightly more complicated + configuration we can select substrings of the server name to + use in the filename so that e.g. the documents for + <samp>www.user.isp.com</samp> are found in + <code>/home/user/</code>. It uses a single <code>cgi-bin</code> + directory instead of one per virtual host.</p> +<pre> +# all the preliminary stuff is the same as above, then + +# include part of the server name in the filenames +VirtualDocumentRoot /www/hosts/%2/docs + +# single cgi-bin directory +ScriptAlias /cgi-bin/ /www/std-cgi/ +</pre> + + <p>There are examples of more complicated + <code>VirtualDocumentRoot</code> settings in <a + href="../mod/mod_vhost_alias.html">the + <code>mod_vhost_alias</code> documentation</a>.</p> + <hr /> + + <h2><a id="combinations" name="combinations">Using more than + one virtual hosting system on the same server</a></h2> + + <p>With more complicated setups you can use Apache's normal + <code><VirtualHost></code> directives to control the + scope of the various virtual hosting configurations. For + example, you could have one IP address for homepages customers + and another for commercial customers with the following setup. + This can of course be combined with conventional + <code><VirtualHost></code> configuration sections.</p> +<pre> +UseCanonicalName Off + +LogFormat "%V %h %l %u %t \"%r\" %s %b" vcommon + +<Directory /www/commercial> + Options FollowSymLinks + AllowOverride All +</Directory> + +<Directory /www/homepages> + Options FollowSymLinks + AllowOverride None +</Directory> + +<VirtualHost 111.22.33.44> + ServerName www.commercial.isp.com + + CustomLog logs/access_log.commercial vcommon + + VirtualDocumentRoot /www/commercial/%0/docs + VirtualScriptAlias /www/commercial/%0/cgi-bin +</VirtualHost> + +<VirtualHost 111.22.33.45> + ServerName www.homepages.isp.com + + CustomLog logs/access_log.homepages vcommon + + VirtualDocumentRoot /www/homepages/%0/docs + ScriptAlias /cgi-bin/ /www/std-cgi/ +</VirtualHost> +</pre> + <hr /> + + <h2><a id="ipbased" name="ipbased">More efficient IP-based + virtual hosting</a></h2> + + <p>After <a href="#simple">the first example</a> I noted that + it is easy to turn it into an IP-based virtual hosting setup. + Unfortunately that configuration is not very efficient because + it requires a DNS lookup for every request. This can be avoided + by laying out the filesystem according to the IP addresses + themselves rather than the corresponding names and changing the + logging similarly. Apache will then usually not need to work + out the server name and so incur a DNS lookup.</p> +<pre> +# get the server name from the reverse DNS of the IP address +UseCanonicalName DNS + +# include the IP address in the logs so they may be split +LogFormat "%A %h %l %u %t \"%r\" %s %b" vcommon +CustomLog logs/access_log vcommon + +# include the IP address in the filenames +VirtualDocumentRootIP /www/hosts/%0/docs +VirtualScriptAliasIP /www/hosts/%0/cgi-bin +</pre> + <hr /> + + <h2><a id="oldversion" name="oldversion">Using older versions + of Apache</a></h2> + + <p>The examples above rely on <code>mod_vhost_alias</code> + which appeared after version 1.3.6. If you are using a version + of Apache without <code>mod_vhost_alias</code> then you can + implement this technique with <code>mod_rewrite</code> as + illustrated below, but only for Host:-header-based virtual + hosts.</p> + + <p>In addition there are some things to beware of with logging. + Apache 1.3.6 is the first version to include the + <code>%V</code> log format directive; in versions 1.3.0 - 1.3.3 + the <code>%v</code> option did what <code>%V</code> does; + version 1.3.4 has no equivalent. In all these versions of + Apache the <code>UseCanonicalName</code> directive can appear + in <code>.htaccess</code> files which means that customers can + cause the wrong thing to be logged. Therefore the best thing to + do is use the <code>%{Host}i</code> directive which logs the + <code>Host:</code> header directly; note that this may include + <code>:port</code> on the end which is not the case for + <code>%V</code>.</p> + <hr /> + + <h2><a id="simple.rewrite" name="simple.rewrite">Simple dynamic + virtual hosts using <code>mod_rewrite</code></a></h2> + + <p>This extract from <code>httpd.conf</code> does the same + thing as <a href="#simple">the first example</a>. The first + half is very similar to the corresponding part above but with + some changes for backward compatibility and to make the + <code>mod_rewrite</code> part work properly; the second half + configures <code>mod_rewrite</code> to do the actual work.</p> + + <p>There are a couple of especially tricky bits: By default, + <code>mod_rewrite</code> runs before the other URI translation + modules (<code>mod_alias</code> etc.) so if they are used then + <code>mod_rewrite</code> must be configured to accommodate + them. Also, mome magic must be performed to do a + per-dynamic-virtual-host equivalent of + <code>ScriptAlias</code>.</p> +<pre> +# get the server name from the Host: header +UseCanonicalName Off + +# splittable logs +LogFormat "%{Host}i %h %l %u %t \"%r\" %s %b" vcommon +CustomLog logs/access_log vcommon + +<Directory /www/hosts> + # ExecCGI is needed here because we can't force + # CGI execution in the way that ScriptAlias does + Options FollowSymLinks ExecCGI +</Directory> + +# now for the hard bit + +RewriteEngine On + +# a ServerName derived from a Host: header may be any case at all +RewriteMap lowercase int:tolower + +## deal with normal documents first: +# allow Alias /icons/ to work - repeat for other aliases +RewriteCond %{REQUEST_URI} !^/icons/ +# allow CGIs to work +RewriteCond %{REQUEST_URI} !^/cgi-bin/ +# do the magic +RewriteRule ^/(.*)$ /www/hosts/${lowercase:%{SERVER_NAME}}/docs/$1 + +## and now deal with CGIs - we have to force a MIME type +RewriteCond %{REQUEST_URI} ^/cgi-bin/ +RewriteRule ^/(.*)$ /www/hosts/${lowercase:%{SERVER_NAME}}/cgi-bin/$1 [T=application/x-httpd-cgi] + +# that's it! +</pre> + <hr /> + + <h2><a id="homepages.rewrite" name="homepages.rewrite">A + homepages system using <code>mod_rewrite</code></a></h2> + + <p>This does the same thing as <a href="#homepages">the second + example</a>.</p> +<pre> +RewriteEngine on + +RewriteMap lowercase int:tolower + +# allow CGIs to work +RewriteCond %{REQUEST_URI} !^/cgi-bin/ + +# check the hostname is right so that the RewriteRule works +RewriteCond ${lowercase:%{SERVER_NAME}} ^www\.[a-z-]+\.isp\.com$ + +# concatenate the virtual host name onto the start of the URI +# the [C] means do the next rewrite on the result of this one +RewriteRule ^(.+) ${lowercase:%{SERVER_NAME}}$1 [C] + +# now create the real file name +RewriteRule ^www\.([a-z-]+)\.isp\.com/(.*) /home/$1/$2 + +# define the global CGI directory +ScriptAlias /cgi-bin/ /www/std-cgi/ +</pre> + <hr /> + + <h2><a id="xtra-conf" name="xtra-conf">Using a separate virtual + host configuration file</a></h2> + + <p>This arrangement uses more advanced <code>mod_rewrite</code> + features to get the translation from virtual host to document + root from a separate configuration file. This provides more + flexibility but requires more complicated configuration.</p> + + <p>The <code>vhost.map</code> file contains something like + this:</p> +<pre> +www.customer-1.com /www/customers/1 +www.customer-2.com /www/customers/2 +# ... +www.customer-N.com /www/customers/N +</pre> + <br /> + <br /> + + + <p>The <code>http.conf</code> contains this:</p> +<pre> +RewriteEngine on + +RewriteMap lowercase int:tolower + +# define the map file +RewriteMap vhost txt:/www/conf/vhost.map + +# deal with aliases as above +RewriteCond %{REQUEST_URI} !^/icons/ +RewriteCond %{REQUEST_URI} !^/cgi-bin/ +RewriteCond ${lowercase:%{SERVER_NAME}} ^(.+)$ +# this does the file-based remap +RewriteCond ${vhost:%1} ^(/.*)$ +RewriteRule ^/(.*)$ %1/docs/$1 + +RewriteCond %{REQUEST_URI} ^/cgi-bin/ +RewriteCond ${lowercase:%{SERVER_NAME}} ^(.+)$ +RewriteCond ${vhost:%1} ^(/.*)$ +RewriteRule ^/(.*)$ %1/cgi-bin/$1 +</pre> + <br /> + <br /> + <!--#include virtual="footer.html" --> + </body> +</html> + |