Scenario

• RedHat Linux 7.2
• Latest 1.4.x Sun JDK
• Tomcat 4.1.12 binary
• Apache 2.0.43 built from source
• jk2 connector binary from jakarta.apache.org

Requirements

Deploy three (in my case) web applications under three different virtual hosts, making the default vhost respond to any name and to the bare IP address.

Installing JDK

Note: download the jdk, not just the jre!

make a symlink named java to j2sdk1.4.1_01/ so that you can easily switch back and forth between different jvms. We will use the same trick for apache and tomcat afterwards.

Now tell your bash shell where to find java binaries: create a file named java.sh in /etc/profile.d with the following content:

do a chmod:

You should get the answer given above. If not chek your environment and make sure that java.sh is executed when opening a new shell. Try to run a java program or the following: java -version.

If you don't like this way of installing java please ignore it. Make sure everything is ok and then jump to the next step.

Installing Apache

Download the latest release, uncompress it, cd into the newly created directory and run the following:

Of course you can customize the installation specifying other modules to enable or whatever you like. Just don't forget to ENABLE-SO, because that's what you need to load the apache-tomcat connector.

Run make and make install. Create the log directories and others (you can skip this if you know how to configure where apache puts its log files -> edit httpd.conf):

Create the symlink /usr/local/apache to /usr/local/apache2.0.43 and test your installation by executing:

Open a browser and point it to the linux box: you should get a page telling you that the apache installation was successful. If that doesn't happen check the logs and troubleshoot: common errors in this configuration are that some directory holding log or configuration files is missing or maybe you have another web server listening on port 80.

Installing Tomcat

Uncompress the tomcat binaries in a directory of your choice. In this howto we will use /opt. Create a symlink named jakarta to the newly created directory so that you have something like the following:

After a few seconds point your browser at the IP of the linux box on port 8080 and you should see the tomcat welcome page. If not check the catalina.out log file in /opt/jakarta/logs and fix all errors until Tomcat comes up.

Configuring Tomcat to listen to Apache ajp13 requests

Here is a sample server.xml file. Please note that the location of directories and log files is absolutely arbitrary and you have to edit it to make it suit your needs.

<!-- Umberto Server Configuration File -->

<Server port="8005" shutdown="SHUTDOWN" debug="0">
  <!-- Define an Apache-Connector Service -->

  <Service name="Tomcat-Apache">
 
   <!-- Define a Coyote/JK2 AJP 1.3 Connector on port 8009 -->
    <Connector className="org.apache.coyote.tomcat4.CoyoteConnector"
               port="8009" minProcessors="5" maxProcessors="75"
               enableLookups="true" redirectPort="8443"
               acceptCount="10" debug="0" connectionTimeout="20000"
               useURIValidationHack="false"
               protocolHandlerClassName="org.apache.jk.server.JkCoyoteHandler"/>

	<Engine name="Apache" defaultHost="www.home.net" debug="0">

      <Logger className="org.apache.catalina.logger.FileLogger"
              prefix="apache_log." suffix=".txt"
              timestamp="true"/>
	  <!-- Access log processes all requests for this virtual host. -->
      <Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="localhost_access_log." suffix=".txt"
                 pattern="common" resolveHosts="false"/>

	<Host name="www.home.net" debug="0"
appBase="/opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-example" 
       unpackWARs="true" autoDeploy="true">
		<Alias>localhost</Alias>
		<Alias>www</Alias>
		<Alias>10.0.0.10</Alias>


		<Context path="" docBase="" debug="1"/>

		<Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="home_access_log." suffix=".txt"
                 pattern="common" resolveHosts="false"/>
	</Host>

	<Host name="www.customer1.it" debug="0"
appBase="/opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-blank" 
       unpackWARs="true" autoDeploy="true">

		<Context path="" docBase="" debug="1"/>

		<Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="cust1_access_log." suffix=".txt"
                 pattern="common" resolveHosts="false"/>
	</Host>

	<Host name="www.customer2.net" debug="0"
appBase="/opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/root" 
       unpackWARs="true" autoDeploy="true">

		<Context path="" docBase="" debug="1"/>

		<Valve className="org.apache.catalina.valves.AccessLogValve"
                 directory="logs"  prefix="cust2_log." suffix=".txt"
                 pattern="common" resolveHosts="false"/>
	</Host>

    </Engine>

  </Service>

</Server>

# list of needed handlers.
handler.list=channelSocket,request
# Override the default port for the channelSocket
channelSocket.port=8009

Configuring Apache virtual hosting

rtfm at http://httpd.apache.org/docs-2.0/vhosts/ In the appendix you can find the httpd.conf file I used to write and test this HOWTO.

Configuring Apache to talk to Tomcat

Download the jk2 shared library for you version of apache and copy it in /usr/local/apache/modules (create the directory if necessary). If you can't find a suitable version of jk2 ask it to the tomcat-user mailing list or download the source and build it yourself (this is another HOWTO).

Create, if you haven't already, the /usr/local/apache/conf directory and create a file named workers2.properties with this content in it:

# only at beginnin. In production uncomment it out
[logger.apache2]
level=DEBUG

[shm]
file=/usr/local/apache/logs/shm.file
size=1048576

# Example socket channel, override port and host.
[channel.socket:localhost:8009]
port=8009
host=127.0.0.1

# define the worker
[ajp13:localhost:8009]
channel=channel.socket:localhost:8009

# Uri mapping
[uri:10.0.0.10/*.jsp]
worker=ajp13:localhost:8009

[uri:www.home.net/*.jsp]
worker=ajp13:localhost:8009

[uri:www.customer1.it/*.jsp]
worker=ajp13:localhost:8009

[uri:www.customer2.net/*.jsp]
worker=ajp13:localhost:8009

Edit http.conf and add the following line in the Modules section:

LoadModule jk2_module modules/mod_jk2.so

Start tomcat and try to load a HTML page in your browser: apache should return the page without problems. Now try with a jsp page: it should display after a little.
If you get errors check that the path and host names (double check also the configuration of DNS with your network administrator) are ok, the directories are readable by both Tomcat and Apache. Again look into the log files.

If everything works go to next section.

The last trick

Now ask your network administrator to set up an alias for your brand new server (use jspsrc if you like to stick to this howto). If you don't have easy access to dns try to edit your hosts file (on the client where you open the browser) and add a line as follows:

10.0.0.10		jspsrc

http://jspsrc

This is clearly a security problem, if not a major annoyance.

What's wrong with the setup we came up so far? The problem is (or should be) that the ajp13 connector can't find a virtual host that matches the jspsrc uri. What we need to do is set up the default virtual host so that ALL *.jsp requests get handled by tomcat.

How do we do it?

Read on if you want to know how.

JK directives in httpd.conf

In addition to the workers2.properties you can put Jk diretives directly into the httpd.conf file (just as you did with jk and webapp). Edit the default virtual host section in httpd.conf and add the following lines in the end, before </VirtualHost>:

    <Location "/*.jsp">
        JkUriSet worker ajp13:localhost:8009 
    </Location>

The jsp source should not be displayed anymore.

Notes

I think a better approach would be to remove all uri directives from workers2.properties and to put them in http.conf as we did in the previous section for the defualt virtual host. Experiment and let me know.

APPENDIX A: httpd.conf

#
# Umberto Nicoletti, 18/10/2002
#

### Section 1: Global Environment

ServerRoot "/usr/local/apache"
ErrorLog logs/error_log

<IfModule !mpm_winnt.c>
<IfModule !mpm_netware.c>
#LockFile logs/accept.lock
</IfModule>
</IfModule>

# ScoreBoardFile: File used to store internal server process information.
<IfModule !mpm_netware.c>
<IfModule !perchild.c>
#ScoreBoardFile logs/apache_runtime_status
</IfModule>
</IfModule>

<IfModule !mpm_netware.c>
PidFile logs/httpd.pid
</IfModule>

Timeout 300

KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 15

<IfModule prefork.c>
StartServers         5
MinSpareServers      5
MaxSpareServers     10
MaxClients         150
MaxRequestsPerChild  0
</IfModule>

<IfModule worker.c>
StartServers         2
MaxClients         150
MinSpareThreads     25
MaxSpareThreads     75 
ThreadsPerChild     25
MaxRequestsPerChild  0
</IfModule>

<IfModule perchild.c>
NumServers           5
StartThreads         5
MinSpareThreads      5
MaxSpareThreads     10
MaxThreadsPerChild  20
MaxRequestsPerChild  0
</IfModule>

# listen on all ports
Listen 80

#
# Dynamic Shared Object (DSO) Support
#
LoadModule jk2_module modules/mod_jk2.so

### Section 2: 'Main' server configuration

<IfModule !mpm_winnt.c>
<IfModule !mpm_netware.c>
#
# If you wish httpd to run as a different user or group, you must run
# httpd as root initially and it will switch.  
#
# User/Group: The name (or #number) of the user/group to run httpd as.
#  . On SCO (ODT 3) use "User nouser" and "Group nogroup".
#  . On HPUX you may not be able to use shared memory as nobody, and the
#    suggested workaround is to create a user www and use that user.
#  NOTE that some kernels refuse to setgid(Group) or semctl(IPC_SET)
#  when the value of (unsigned)Group is above 60000; 
#  don't use Group #-1 on these systems!
#
User nobody
Group #-1
</IfModule>
</IfModule>

ServerAdmin whatever@you.want
ServerName www.home.net
UseCanonicalName Off

#
# The following directives define some format nicknames for use with
# a CustomLog directive (see below).
#
LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
LogFormat "%h %l %u %t \"%r\" %>s %b" common
LogFormat "%{Referer}i -> %U" referer
LogFormat "%{User-agent}i" agent

LogLevel debug
CustomLog logs/access.log common

DocumentRoot "/opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-example"

<Directory /opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-example>
    Options None
    AllowOverride None
</Directory>

DirectoryIndex index.html index.jsp

<Directory />
    Options None
    AllowOverride None
</Directory>

<Files ~ "^\.ht">
    Order allow,deny
    Deny from all
</Files>

<Location /WEB-INF/>
    Order Allow,Deny
</Location>

NameVirtualHost *

<VirtualHost *>
    ServerName www.home.net
	ServerAlias www
	ServerAlias localhost
    ServerAdmin sysmaster@arpa.veneto.it
    DocumentRoot /opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-example

    ErrorLog logs/home.net-errorlog
	CustomLog logs/home.net-access.log common

    <Location "/*.jsp">
        JkUriSet worker ajp13:localhost:8009 
    </Location>
</VirtualHost>

<VirtualHost *>
    ServerName www.customer1.it
    ServerAdmin sysmaster@arpa.veneto.it
    DocumentRoot /opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/struts-blank
    ErrorLog logs/cust1-errorlog
</VirtualHost>

<VirtualHost *>
    ServerName www.customer2.net
    ServerAdmin sysmaster@arpa.veneto.it
    DocumentRoot /opt/jakarta-tomcat-4.1.12-LE-jdk14/webapps/root
    ErrorLog logs/cust2-errorlog
</VirtualHost>