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Monitoring

http://www.lambdaprobe.org/d/download.htm

Connecting tomcat and apache using mod_jk or mod_proxy

One can connect tomcat to apache via mod_proxy or mod_jk.

Via mod_proxy_ajp on apache 2.2

Connecting tomcat and apache2.2 couldn't be easier. Apache2.2 has build-in support for AJP protocol. It's considerably easier than mod_jk. Here's a quick example on mounting the tomcat example webapps.

LoadModule proxy_module modules/mod_proxy.so

LoadModule proxy_ajp_module modules/mod_proxy_ajp.so

<IfModule proxy_module>

ProxyRequests Off

<Proxy *>

    Order allow,deny

    Allow from all

</Proxy>

ProxyPass /assets !

ProxyPass /css !

ProxyPass /scripts !

ProxyPass /js !

ProxyPass  /  http://localhost:8080/

ProxyPassReverse /  http://localhost:8080/

ProxyPass /examples ajp://localhost:8009/examples

ProxyPassReverse /examples ajp://localhost:8009/examples

# Or do it with rewrite

        RewriteEngine On

        RewriteCond %{REQUEST_URI} /.*\.jsp

        RewriteRule ^/(.*) ajp://localhost:8009/$1 [P]

        RewriteCond %{REQUEST_URI} /(servlet|examples).*

        RewriteRule ^/(.*) ajp://localhost:8009/$1 [P]

# Negate rewrite

    <Proxy balancer://internalBalancer stickysession=JSESSIONID>

                BalancerMember ajp://10.10.10.3:8509

                BalancerMember ajp://10.10.10.8:8509

        </Proxy>

    RewriteCond %{REQUEST_URI} !\.htm$

    RewriteRule /(.*) ajp://someBalancer/$1 [P]

# Enables maintenance page

RewriteEngine On

# Check for maintenance page

RewriteCond %{REQUEST_URI} !(maintenance.html$)

RewriteCond %{DOCUMENT_ROOT}/maintenance.html -f

RewriteRule .* /maintenance.html [R,L]

# Forward everything to jboss

RewriteCond %{REQUEST_URI} !(maintenance.html$)

RewriteRule ^/(.*) ajp://localhost:8009/$1 [P]

</IfModule>

Load balancing example

<IfModule proxy_module>

ProxyRequests Off

# Defining a balancer

<Proxy balancer://tomcatfarm>

    Order allow,deny

    Allow from all

    BalancerMember ajp://localhost:8009/examples loadfactor=50

    BalancerMember ajp://192.168.13.10:8009/examples loadfactor=10

    # Member to use only when no other members are available

    BalancerMember ajp://10.0.0.1:8009/examples status=+H

    # Available methods byrequests, bytraffic

    ProxySet lbmethod=byrequests 

</Proxy>

# Mapping /examples to your balancer

<Location /examples>

    SetEnv BALANCER_SESSION_STICKY jsessionid

    ProxyPass balancer://tomcatfarm/ 

    ProxyPassReverse balancer://tomcatfarm/ 

</Location>

# Enable balancer manager to show load statistics

<Location /balancer-manager>

    SetHandler balancer-manager

    Order allow,deny

    Allow from all

</Location>

</IfModule>

Balancer manager for the example above

Via tomcat-connector (mod_jk)

mod_jk has been around for some time. Installation is straight-forward on modern linux distribution.

Note: On Solaris, make, m4, libtool, automake and autoconf should be installed. Do a buildconf.sh before configure. Also export LD_LIBRARY_PATH="/usr/local/lib"

./configure --with-apxs=/usr/sbin/apxs

# Other options:

# --with-java-home=${JAVA_HOME} --with-java-platform=2 -enable-jni

make && make install

mod_jk setup

workers.properties

# Generic template - v1.0 - Ken Fong

# take out loadbalancer if talking to 1 tomcat.

workers.apache_log=/var/log/httpd/

workers.tomcat_home=/opt/tomcat

workers.java_home=/opt/java

ps=/

# Define list of workers that will be used

# for mapping requests

# When load-balancing is used, real workers should not be listed here.

worker.list=loadbalancer,status

# Definte default worker settings

worker.default.port=8009

worker.default.type=ajp13

worker.default.lbfactor=1

# no need to set socket_timeout in most case. default is 0

worker.default.socket_timeout=120

# for firewalled backend

worker.default.socket_keepalive=True

# ping listener before connect, timeout 5s

worker.default.ping_mode=P

worker.default.ping_timeout=5000

worker.default.connect_timeout=5000

# timeout between request and first response packet. set to longer in case of long running servlets

worker.default.reply_timeout=60000

# ping/ping before forwarding a request

# worker.prepost_timeout=5000

# worker.default.connection_pool_timeout=180

# Define Node1

worker.node1.reference=worker.default

worker.node1.host=192.168.17.101

# Define Node 2

worker.node2.reference=worker.default

worker.node2.host=192.168.17.102

# define load balancer

worker.loadbalancer.type=lb

worker.loadbalancer.balance_workers=node1,node2

worker.loadbalancer.sticky_session=true

# Load balancing method can be [R]equest, [S]ession, [T]raffic, or [B]usyness

worker.loadbalancer.method=R

# How runtime data are sync-ed. [O]ptimistic or [P]essimistic

worker.loadbalancer.lock=O

# Status worker for managing load balancer

worker.status.type=status

httpd.conf

# Load mod_jk

#

LoadModule    jk_module  libexec/mod_jk.so

#AddModule     mod_jk.c

# Configure mod_jk

#

JkWorkersFile /usr/local/jakarta-tomcat/conf/workers.properties

JkLogFile     /usr/local/apache/logs/mod_jk.log

JkLogLevel    warn

# Set the following if you want all vhosts to inherhit JkMounts from global 

JkMountCopy All

# Interesting option to try out. possibly eliminate the need to jkmount the same url twice

JkOptions +ForwardDirectories 

# Sample mount point

JkMount /jmx-console ajp13

JkMount /jmx-console/* ajp13

# First Virtual Host.

#

<VirtualHost 10.0.0.1:80>

  DocumentRoot /web/host1

  ServerName host1.apache.org

  JkMount /*.jsp ajp13

  JkMount /servlet/* ajp13

</VirtualHost>

# Second Virtual Host. Also accessible via HTTPS

#

<VirtualHost 10.0.0.2:80>

  DocumentRoot /web/host2

  ServerName host2.apache.org

  JkMountCopy On

</VirtualHost>

<VirtualHost 10.0.0.2:443>

  DocumentRoot /web/host2

  ServerName host2.apache.org

  SSLEngine On

  JkMountCopy On

</VirtualHost>

JkMount exclusion

Sometimes, you need to forward all requests to tomcat/jboss, except for maybe the images directory, which will be served out of apache. Here's how you can do it

JkMount /* worker1
SetEnvIf Request_URI "/images/*" no-jk

Then a fairly simply tomcat startup script

tomcat

#!/bin/sh                            

# tomcat Startup script for          

#                                    

# chkconfig: 2345 90 10              

# description: custom tomcat script to restart tomcat as the tomcat user

# @author                : Ken Fong                                     

# @origdate             : Wed Feb 27 11:22:32 EST 2008      

# @revision              : 0.2            

# Linux init functions

. /etc/rc.d/init.d/functions

export TOMCAT_HOME=/opt/tomcat         

export CATALINA_PID=$TOMCAT_HOME/logs/tomcat.pid

export JAVA_HOME=/usr                  

#export JAVA_OPTS="-Xmx512m"           

TOMCAT_USER=tomcat                   

RETVAL=0

LOCKFILE=/var/lock/subsys/tomcat

start() {

                echo -n "Starting tomcat..."

                chown -R $TOMCAT_USER:$TOMCAT_USER $TOMCAT_HOME

                ulimit -n 4096                                 

                su $TOMCAT_USER -c $TOMCAT_HOME/bin/startup.sh 

                # On BSD # su -m $TOMCAT_USER -c $TOMCAT_HOME/bin/startup.sh

                echo "Tomcat started with PID `cat $CATALINA_PID`"          

                RETVAL=$?                                                   

                echo                                                        

                [ $RETVAL = 0 ] && touch ${LOCKFILE}                        

                return $RETVAL

}

stop() {

                echo -n "Stopping tomcat..."

                su $TOMCAT_USER -c $TOMCAT_HOME/bin/shutdown.sh

                # on BSD # su -m $TOMCAT_USER -c $TOMCAT_HOME/bin/shutdown.sh

                #ps auxww | grep "$TOMCAT_HOME " | grep -v grep | awk '{print $2}' | xargs kill -9

                echo "Killing tomcat process in case normal shutdown was ineffective"

                if [ -n "`pidfileofproc $CATALINA_PID`" ] ; then

                    killproc $CATALINA_PID

                    # BSD # kill -9 `cat $CATALINA_PID`

                fi

                RETVAL=$?

                echo

                [ $RETVAL = 0 ] && rm -f ${LOCKFILE}

                return $RETVAL

}

case "$1" in

start)

                start

;;

stop)

                stop

;;

restart)

                stop

                sleep 10

                start

;;

esac

exit 0

Tomcat virtual host

If in some case you need to create virtual hosts with a dedicated webapps repository, add these to server.xml:

server.xml

<Host name="www.newdomain.com" appBase="/home/sites/newdomain.com"

        unpackWARs="true" autoDeploy="true"

        xmlValidation="false" xmlNamespaceAware="false">

        <Alias>newdomain.com</Alias>

        <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"

               prefix="newdomain-" suffix=".log" pattern="common" resolveHosts="false"/>

</Host>

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