Hi,
I hv clustered 2 Tomcat (version 5.0.18) instances on 2 physically
different machines A and B.
Individually accessible as
http://machineA:8080 <http://machinea:8080/> and
http://machineB:8080 <http://machineb:8080/>
I have Apache 2.0.54 installed on machine A and following the tomcat doc
http://jakarta.apache.org/tomcat/tomcat-5.0-doc/balancer-howto.html
I am trying to use Apache mod_rewrite to load balance/
failover between my 2 tomcat instances.
As per the doc modified the <engine> element in server.xml
to include the jvmRoute attribute
Configuring Apache was a headache.
The documentation assumes the reader is an expert with Apache.
It is not completely accurate. The reader cannot use it as is.
For instance it talks of creating balancer.conf but uses servers.conf in
http.
Anyways I discovered it and created a balancing.conf for
mod_rewrite as explained.
Edited apache's httpd.conf as given in the tomcat doc.
And with both tomcat instances working browsed
to
http://localhost/servlets-examples/servlet/RequestInfoExample
But it did not work. Error log gave:
File does not exist:
proxy:http://machineA:8080/servlets-examples/servlet/RequestInfoExample
But I could get the expected page when I replaced [P, L]
in the RewriteRule for <Location /servlets-examples> with only [L]
The funny thing however is I browse to
http://localhost/servlets-examples/servlet/RequestInfoExample
but that later automatically changes to either
http://machineA:8080/servlets-examples/servlet/RequestInfoExample or
http://machineB:8080/servlets-examples/servlet/RequestInfoExample
depending upon which Tomcat instance served my request.
Any clues as to why the URL in the browser changes?
PS: My entries in httpd.conf
RewriteMap SERVERS rnd:<<path to the balancer.conf
created above>>
<Location /servlets-examples>
RewriteEngine On
RewriteCond "%{HTTP_COOKIE}"
"(^|;\s*)jsessionid=\w*\.(\w+)($|;)"
RewriteRule "(.*)"
"http://${SERVERS:%2}%{REQUEST_URI}"; [P,L]
RewriteRule "^.*;jsessionid=\w*\.(\w+)($|;)"
"http://${SERVERS:$1}%{REQUEST_URI}"; [P,L]
RewriteRule "(.*)"
"http://${SERVERS:ALL}%{REQUEST_URI}"; [P,L]
</Location>
<< I had to replace [P,L] with [L] to make it work>>
rgds,
G1
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