Subject: Side notes for mod_jk installation 64-bit
Author: AwsEC2
In response to: Integrate Apache httpd with Tomcat plus failover
Posted on: 08/30/2012 02:43:24 PM
1) Always get the latest version
$ cd /home/ec2-user
$ mkdir mod_jk
$ cd mod_jk
$ curl http://apache.osuosl.org/tomcat/tomcat-connectors/jk/
tomcat-connectors-1.2.37-src.tar.gz > tomcat-connectors-1.2.37-src.tar.gz
$ tar xzf tomcat-connectors-1.2.37-src.tar.gz
$ cd tomcat-connectors-1.2.37-src/native
$ ./configure --with-apxs=/usr/sbin/apxs
$ make
$ sudo make install
2) $ make may return 'make not found' You may have to install first by
# yum install make
3) The install may change the location depending on your OS For 32-bit: /usr/lib/httpd/modules/mod_jk.so
For 64-bit: /usr/lib
64/httpd/modules/mod_jk.so
4) Accordingly, a working httpd.conf
# vi /etc/httpd/conf/httpd.conf
# Load mod_jk module
LoadModule jk_module /usr/lib64/httpd/modules/mod_jk.so
# Where to find workers.properties
JkWorkersFile /etc/httpd/conf/workers.properties
# Where to put jk shared memory
JkShmFile /var/log/httpd/mod_jk.shm
# Where to put jk logs
JkLogFile /var/log/httpd/mod_jk.log
# Set the jk log level [debug/error/info]
JkLogLevel info
# Select the timestamp log format
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
<VirtualHost *:80>
ServerName example1.com
ServerAlias www.example1.com
DocumentRoot /home/ec2-user/example1.com/html
SuexecUserGroup ec2-user ec2-user
<Directory /home/ec2-user/example1.com/html>
Options Indexes Includes FollowSymLinks
AllowOverride All
</Directory>
# Send servlet for context /examples to worker named worker1
JkMount /examples/servlets/* worker1
# Send JSPs for context /examples to worker named worker1
JkMount /examples/*.jsp worker1
</VirtualHost>
# /etc/init.d/httpd start
Starting httpd: [ OK ]
>
> On 11/02/2011 07:12:46 PM
Linux wrote:
------- ----------
www.exmaple1.com ---| | | |
| | mod_jk | tomcat |
| httpd |------------|(primary) |
www.exmaple2.com ---| | | | |
|_______| | |__________|
|
| ----------
| | |
| | tomcat |
|--|(failover)|
| |
|__________|
A load balancer is a worker that does not directly communicate with Tomcat. Instead it is responsible for the management of several "real" workers, called members or sub workers of the load balancer.
A practical example given here is to use loadbalancer to provide high-availability service with a failover tomcat server.
# The dvanced router LB worker
worker.list=router
worker.router.type=lb
worker.router.balance_workers=worker1,worker2
# Define the first member worker
worker.worker1.type=ajp13
worker.worker1.host=myhost1
worker.worker1.port=8009
# Define preferred failover node for worker1
worker.worker1.redirect=worker2
# Define the second member worker
worker.worker2.type=ajp13
worker.worker2.host=myhost2
worker.worker2.port=8009
# Disable worker2 for all requests except failover
worker.worker2.activation=disabled
The redirect flag on worker1 tells the load balancer to redirect the requests to worker2 in case that worker1 has a problem. In all other cases worker2 will not receive any requests, thus acting like a hot standby.
References:
