Goal:

• Learn how to configure apache as
  • web server.
  • cache server
  • reverseproxy
• Learn how to form a single cluster using reverseproxy.
• Learn how to use ab to evaluate the web server performance.

Assignment Date: 2/11/2009
Due Day: 2/18/2009
Related documents:

• Apache httpd version 2.2 document: http://httpd.apache.org/docs/2.2/
• Content cache: http://httpd.apache.org/docs/2.2/caching.html

Description:

Part 1. Configure apache to run as a web server

• In this exercise, we will learn how to configure apache httpd to run as a web server.
• In the following description, we assume jlogan is your account; the last three digits of your SID is 345; you are using blanca for this exercise. Modify the scripts/configuration accordingly by replacing your account name and related info.
• We will carry out this exrecise on CS Unix machines (windom, blanca, or shavano, but not on cs). If you find they are busy or not responding, you can choose to run your exercises on viva. However the prefix of the full file path will change from /users/server/students to /home
• In /users/server/students/cs526/public_html/httpd/httpd-2.2.11 we have compiled the apache httpd version 2.2.11 with basic cache and proxy modules. There is a httpd program in bin directory and the modules is in modules directory. This is the Apache HyperText Transfer Protocol (HTTP) server program. It is designed to be run as a standalone daemon process.
• Read man page with "man httpd" for more info. The related http-2.2 version documents are available at http://httpd.apache.org/docs/2.2
  

  SYNOPSIS
  httpd [ -X ] [ -R libexecdir ] [ -d serverroot ] [ -f con-fig ] [ -C directive ] [ -c directive ] [ -D parameter ]
  

• If "/usr/sbin/httpd -d /users/server/students/cs526/public_html/apache/ws1 -X" is run, the httpd program will treat /users/server/students/cs526/public_html/apache/ws1 as serverroot directory and read the directives in the conf/httpd.conf file for configuring the apache server. -X is for debugging purpose, it indicates to the httpd daemon that do not fork spare child process for improving performance. Just run a single standalone process.
• The Apache provides a rich set of directives for configuring/customizing the web server. A subset of directives are realized by an Apache module. See http://httpd.apache.org/docs/2.2/mod/directives.html for the set of runtime directives.
• An example of httpd.conf is
  
  LoadModule log_config_module /etc/httpd/modules/mod_log_config.so
  LoadModule access_module /etc/httpd/modules/mod_access.so

  User jlogan
  ServerName blanca.uccs.edu
  Listen 8388

  DocumentRoot /users/server/students/jlogan/public_html/apache/ws1/htdocs

  ErrorLog logs/error_log
  TransferLog logs/access_log
  PidFile logs/httpd.pid

  
  
• The first directive LoadModule tells the httpd program to dynamically load in /etc/httpd/modules/mod_log_config.so as dynamic shared object (very much like dll). The log_module code deals with creating error log entries in the log files.
• Access_module deals with creating access log entries in the log files.
• User directives tells httpd to run itself as jlogan account.
• ServerName tells httpd the domain to use when displaying error msg.
• Listen directive tells httpd to listen to port 8388 for incoming http requests. We need to enter http://blanca.ccs.edu:8388/ to access this webserver.
• DocumentRoot specifies the actual path to the default web document directory.
• ErrorLog specifies the name of the file for saving error log records.
• TransferLog specifies the name of the file for saving the access records.
• PidFile specifies the names fo the files for saving the process id of the httpd server. It can be used by system admin to restart or stop the httpd server. Note that the CS Unix machines are currently running httpd 2.2.3 (/usr/sbin/httpd) and the modules are located in /etc/httpd/module.
  
  You can try to run "telnet cs.uccs.edu 80" and type "GET / HTTP/1.0 <enter><enter>" to find out the server version:
  
  [cs526@blanca ~]$ telnet cs.uccs.edu 80
  Trying 128.198.162.68...
  Connected to cs.uccs.edu (128.198.162.68).
  Escape character is '^]'.
  GET / HTTP/1.0
  HTTP/1.1 200 OK
  Date: Mon, 09 Feb 2009 23:45:12 GMT
  Server: Apache/2.2.3 (CentOS)
  
• In httpd version 2.2.0, the User, ServerName, ErrorLog are in "core" or mpm (multi-process module)" basic modules which constitute the basic httpd program. There are no need to use LoadModule directive

Part1. Exercise1: Configure a simple apache server (ws1)

• Login to blanca.
• Copy the directory ~cs526/public_html/apache to your ~<login>/public_html/cs526 directory, using "cp -r ~cs526/public_html/apache ~<login>/public_html/cs526.
• cd public_html/cs526/apache/ws1/conf
• edit httpd.conf file by replacing all LOGIN instances with your own login name on CS Unix machines. In other words,
  • Replace parameter of the User directive with your own account.
  • Replace parameter of DocumentRoot and point to your own htdocs directory.
• Replace the port number with 8<last 3 digits of your SID> in the Listen directive. Say from 8822 to 8345 assume 345 are the last 3 digits of your SID.
• Make sure you have mime.types in your conf directory (new apache2 requirement).
• "cd ../htdocs" to web server default document directory.
• Edit the index.html in htdocs directory to include "created by <login> on blanca" where <login> is your login name.
• Edit the cmd file substitute the "LOGIN/public_htlm" string there with "<your loginname>/public_html".
• Run the apache web server with "./cmd &"
  which is equivalent to run
  "/users/server/students/cs526/public_html/httpd/httpd-2.2.11/bin/httpd -d /users/server/students/LOGIN/public_html/cs526/apache/ws1 -X & "
• Go to any browser and enter "http://blanca.uccs.edu:8<last 3 digits of your SID>", e.g., http://blanca.uccs.edu:8345/, and see if the web page shows up.
• Check the logs in /users/server/students/<yourloginname>/public_html/apache2/ws1/logs/access_log and see the access records is created. You can also type the url http://cs.uccs.edu/~cs591/apache/ws1/logs/access_log, assume cs591 is your login.
  

Part1. Exercise2: Setup web server 2 on shavano

• Login to shavano.
• cd public_html/apache/cs526/ws2
• Repeat the above steps for shavano web site.
• "cd ../htdocs" to web server default document directory.
• Edit the index.html in htdocs directory to include "created by <login>" where <login> is your login name.
• Edit the cmd file substitute the "LOGIN/public_html" string there with "<your loginname>/public_html".
• Run the apache web server with "./cmd &"
  which is
  "/users/server/students/cs526/public_html/httpd/httpd-2.2.11/bin/httpd -d /users/server/students/<your loginname>/public_html/cs526/apache/ws2 -X"
• Test it with http://windom.uccs.edu:8345/
  

Part1. Exercise3: Setup web server 3 on windom

• login to windom.
• cp -r ws1 ws3 to create ws3 directory.
  Repeat the above steps for shavano web site.
• Edit the httpd.conf file and web page files in ws3/conf/htdocs directory to reflect the machine windom which will serve the web page.
• Under htdoc directory, create a subdirectory personnel and a personnel web page with "this is windom personnel web page " as content in the htdocs directory.
• Run the web server. See if you can access the personnel web page, and leave some access records.

• In your apache directory, there is a proxy subdirectory.
• login to windom and cd to the proxy directory.
• Edit the conf/httpd.conf with your User account and Port number.
  
  LoadModule cache_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_cache.so
  LoadModule disk_cache_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_disk_cache.so
  LoadModule proxy_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_proxy.so
  LoadModule proxy_http_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_proxy_http.so
  
  User jlogan
  ServerName windom.uccs.edu
  ProxyRequests on
  CacheRoot cache
  CacheEnable disk /
  CacheDirLevels 3
  CacheDirLength 3
  Listen 9345
  
  ErrorLog logs/error_log
  TransferLog logs/access_log
  PidFile logs/httpd.pid
  
  
• Port directive is replaced by Listen directive.
• Replace 9345 with 9<the last 3 digits of your SID> on the above Listen directive
  
• Add CacheDirLevels and CacheDirLength directive to the httpd.conf and change the default settings to 2 and 3 respectively. See directive info at http://httpd.apache.org/docs/mod/directives.html
• Run the proxy cache server with "./cmd & " make sure to change the web site directory.
• Setup your browser to use the proxy server as follows:
  • On Internet Explorer,
    • Select Tool | Internet option...
    • Select Connections tab and click the LAN Settings button.
  • Check "Use a proxy server for your LAN" and enter "windom.uccs.edu" as address and "9<last3digts of your SID>" for the port number. This is port number your cache server is listening.
  • Click OK.
  • On firefox browser,
    • Select Tools | options
    • Click Advanced icon and Network tab, click Settings
    • Click "Manual proxy configuration"
    • Enter windom.uccs.edu as HTTP Proxy text entery; and 9<the last 3 digits of SID> as port number
    • Click OK
  • On Netscape/mosaic browser,
    • Select Edit | Preference, Preference window appears.
  • Double click on the "advanced menu" in the catalog section, it opens out more choices.
  • Select the Proxies menuitem Click manual proxy configuration
  • Enter shavano.uccs.edu for HTTP Proxy:
  • Enter 8<last 3digits of SID> for Port:
  • Click OK.
• Enter the url to your personal web page for CS526 in the address box of your IE browser.
• Locate your personal web page in the cache directory.
• Include the url of the cached docuement in your hw2 web page. It should have the followign prefix http://cs.uccs.edu/~<login>/cs526/apache/proxy/cache/ and indicate the first line and the HTTP header section of the cached file. Verify that the path to the cached document indeed contained the subdirectory name followed the specification of CacheDirLength directive.
• Try downloading a medium file such as http://mirrors.isc.org/pub/apache/httpd/httpd-2.2.11.tar.bz2 twice. The second download should be quicker due to caching.
• After the exercise, do not forget to uncheck the "Use a proxy server for your LAN" Internet option. Otherwise you IE will not work. If you use firefox, select "No proxy" radio button option on the Connection Settings dialog window. Remove the large file(s) from cache afterwards.
• Question 2.1. Why we put cached documents in directories of different level as opposed to put them all in a single cache directory?
• Question 2.2. Why the cached document is saved with a file name generated by applying hash on the url?
• Question 2.3. One of the HTTP headers in the cached document file is the last modified date. In what metaheader will the cache server send this value out? To whom? (Hint: http://cs.uccs.edu/~cs522/hw/hwF2004/hw.htm#hw1 exercise 2.4; http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html#sec13).

• An apache web site template is availabe in apache/reverseproxy directory.
• login to windom and cd to public_html/cs526/reverseproxy directory.
• Edit the conf/httpd.conf with your User account and Port number.
  
  LoadModule proxy_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_proxy.so
  LoadModule proxy_http_module /users/server/students/cs526/public_html/httpd/httpd-2.2.11/modules/mod_proxy_http.so
  
  User jlogan
  ServerName windom.uccs.edu
  ProxyRequests on
  Listen 10345
  
  DocumentRoot htdocs
  
  ProxyPass /eng/ http://blanca.uccs.edu:8345/eng/
  ProxyPassReverse /eng/ http://blanca.uccs.edu:8345/eng/
  
  ProxyPass /sales/ http://shavano.uccs.edu:8345/sales/
  ProxyPassReverse /sales/ http://shavano.uccs.edu:8345/sales/
  
  ErrorLog logs/error_log
  TransferLog logs/access_log
  PidFile logs/httpd.pid
  
• 
  
  
• ProxyPass directive tells the httpd to pass any url request with /eng as prefix to blanca web server.
• ProxyPassReverse tells the httpd to modify the Location header value return from the domain name of the real web server to windom.uccs.edu. Therefore the client will not see replies from different web servers. They are all from windom.uccs.edu.
• Add windom as a "local" web server where the windom reverseproxy server will forward all web pages with /personnel as prefix in the url to windom.
• Run blanca, shavano, and windom web servers according to Exercise 1.
• Run windom reverseproxy server.
• Access http://windom.uccs.edu:10<last3digitsofSS#>/eng/eng.html
• Access http://windom.uccs.edu:10<last3digitsofSS#>/sales/sales.html
• Access http://windom.uccs.edu:10<last3digitsofSS#>/personnel/personnel.html
• See if the return web pages are indeed from the right web server.

Exercise 4. Evaluate Web Server Performance using httperf.

Create a homework web page hw2.html in your cs526 personal web page directory