Homeworks

Goal:

Learn how to configure apache as
- web server.
- cache server
- reverseproxy
Learn how to from a single cluster using reverseproxy.
Learn the basic facts about the content delivery network.

Assignment Date: 9/9/2002
Due Day: 9/18/2002
Description:

Exercise 1. Configure apache to run as a web server

In this exercise, we will learn how to configure apache to run as a web server.
On our CS Unix machines, there is a httpd program in /usr/sbin/. It 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.

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/ws2 -X" is run, the httpd program will treat /users/server/students/cs526/public_html/apache/ws2 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.
An example of httpd.conf is

LoadModule config_log_module /etc/httpd/modules/mod_log_config.so
LoadModule access_module /etc/httpd/modules/mod_access.so
User cs526
ServerName sanluis.uccs.edu
Port 8388

DocumentRoot /users/server/students/cs526/public_html/apache/ws2/htdocs

ErrorLog logs/error_log
TransferLog logs/access_log
PidFile logs/httpd.pid
The first directieve 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 deal with creating access log entries in the log files.
User directives tells httpd to run itself as cs526 account.
ServerName tells httpd the domain to use when displaying error msg.
Port directive tells httpd to use 8388.
DocumentRoot specifies the actual path to the default web document directory.
EorrLog 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.
For this exercise, we would like you to copy the directory ~cs526/public_html/apache to your ~<login>/public_html directory, using "cp -r ~cs526/public_html/apache ~<login>/public_html.
login to blanca.
cd public_html/apache/ws1/conf/
edit httpd.conf file by replacing the account on User directive with your own account.
replace the port number with 8<last 3 digits of your SS#> in the Port directive.
Run the apache web server as "/usr/sbin/httpd -d /users/server/students/<login>/public_html/apache/ws1 -X"
Go to any browser and enter "http://blanca.uccs.edu:8<last 3 digits of your SS#>/index.html" and se
e if the web page shows up.
Check the logs in /users/server/students/cs526/public_html/apache/ws1/log/access_log and see the access records is created.
Email me the url of the access_log file.
Repeat that for sanluis but instead of public_html/apache/ws1/conf/ use public_html/apache/ws2/conf/. Use "/usr/sbin/httpd -d /users/server/students/<login>/public_html/apache/ws2 -X" as command for starting web server.
cp -r ws1 ws3 to create ws3 directory.
login to shavano. Edit the httpd.conf file and web page files in ws3/conf/htdocs directory to reflect the machine shavano which will serve the web page. Create a subdirectory personnel and a personnel web page with "this is shavano personnel web page " as content in the htdocs directory.
Run the web server and leave some access records.

Exercise 2. Setup Cache Server

In your apache directory, there is a proxy subdirectory.
login to crestone and cd to the proxy directory.
Edit the conf/httpd.conf with your User account and Port number.
LoadModule proxy_module /etc/httpd/modules/libproxy.so
LoadModule config_log_module /etc/httpd/modules/mod_log_config.so
LoadModule access_module /etc/httpd/modules/mod_access.so
User cs526
ServerName crestone.uccs.edu
ProxyRequests on
CacheRoot cache
CacheSize 100000
Port 8388

ErrorLog logs/error_log
TransferLog logs/access_log
PidFile logs/httpd.pid
Add CacheDirLevels and CacheDirLength directive to the httpd.conf and change the default settings to 2 and 3 respectively. See directive info at http://httd.apache.org/docs/mod/directives.html
Go the cache subdirectory and clean it up by "rm -r *" note that this is a dangerous operation.
Run the cache server with "/usr/sbin/httpd -d /users/server/students/<login>/public_html/apache/proxy -X"
Setup your browser to use the proxy server as follows:
On Internet Explore, select Tool | Internet option... Select Connections tab and click the LAN Settings button.
Check "Use a proxy server for your LAN" and enter "crestone.uccs.edu" as address and "8<last3digts of your SS#>" for the port number. This is port number your cache server is listening. 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. Report the path to that .html file and the first line and the HTTP header section of the cached file. After the exercise, do not forget to uncheck the "Use a proxy server for your LAN" Internet option.

Exercise 3. Setup ReverseProxy Server/Cluster.

An apache web site template is availabe in apache/reverseproxy directory.
login to crestone and cd to reverseproxy directory.
Edit the conf/httpd.conf with your User account and Port number.
LoadModule proxy_module /etc/httpd/modules/libproxy.so
LoadModule config_log_module /etc/httpd/modules/mod_log_config.so
LoadModule access_module /etc/httpd/modules/mod_access.so
User cs526
ServerName crestone.uccs.edu
#ProxyRequests on
Port 8388

DocumentRoot /users/server/students/cs526/public_html/apache/reverseproxy/htdocs/

ProxyPass /eng/ http://blanca.uccs.edu:8388/eng/
ProxyPassReverse /eng/ http://blanca.uccs.edu:8388/eng/

ProxyPass /sales/ http://sanluis.uccs.edu:8388/sales/
ProxyPassReverse /sales/ http://sanluis.uccs.edu:8388/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 crestone.uccs.edu. Therefore the client will not see replies from different web servers. They are all from crestone.uccs.edu.
Add shavano as a web server where crestone reverseproxy server will forward all web pages with /personnel as prefix in the url.
Run blanca, sanluis, and shavano web servers according to Exercise 1.
Run crestone as reverseproxy server.
Access http://crestone.uccs.edu:8<last3digitsofSS#>/eng/eng.html
Access http://crestone.uccs.edu:8<last3digitsofSS#>/sales/sales.html
Access http://crestone.uccs.edu:8<last3digitsofSS#>/personnel/personnel.
See if the return web pages are indeed from the right web server.

Exercise 4. CDN related Questions

In the CDN system, we can use client cache server, edge cache server, and mirror server. Discuss the advantages and disadvantages of using these three different type of cache server. Point out one or two situations where each type are most effective (compared with others).
ReverseProxy provided by apache can be considered as URL switch (swithcing based on the url value). What is the performance bottleneck in a cluster using reverserpoxy? What is the best situation to use it?

CS526 F2002 Homeworks

Homework #1. Set up web page, due 9/9/2002

Homework#2: Configure a web cluster using Apache ReverseProxy due 9/18/2002

Homework#3: Configure a Linux Secure Content Switch, part1 due 10/21/2002; part2 due 10/28/2002

Homework #4. Configure Intel 7110 SSL Accelerator and 7280 Content Switch due 11/13/2002

Homework #5. Customize JSP Tag and XML/DTD due 12/7/2002

Homework #2. Configure a web cluster using Apache ReverseProxy.