With the release of Grizzly 1.9.11, it is now possible to cluster/load balance your GrizzlyAdapter using Apache!

As I described in the previous entry on the topic(I,II,II,IV, V, VI), it is quite simple to embed Grizzly using its' extension point: GrizzlyAdapter:

        GrizzlyWebServer ws = new GrizzlyWebServer("/var/www");
        try{
            ws.addGrizzlyAdapter(new GrizzlyAdapter(){  
                
                public void service(GrizzlyRequest request, GrizzlyResponse response){
                    try {
                        response.getWriter().println("Grizzly is so cool!!!");
                    } catch (IOException ex) {                        
                    }
                }
            });
            ws.start();
        } catch (IOException ex){
            // Something when wrong.
        }

Now let's assume you want to add clustering/load balancing support to your GrizzlyAdapter. To add such support, let's use Apache 2 and mod_jk. To install mod_jk and Apache, just install mod_jk module (see here for an example):

LoadModule jk_module /usr/apache2/httpd/modules/mod_jk.so
JkWorkersFile /etc/apache2/conf/worker.properties
# Where to put jk logs
JkLogFile /var/log/apache2/mod_jk.log
# Set the jk log level [debug/error/info]
JkLogLevel debug
# Select the log format
JkLogStampFormat "[%a %b %d %H:%M:%S %Y] "
# JkOptions indicate to send SSL KEY SIZE,
JkOptions +ForwardKeySize +ForwardURICompat -ForwardDirectories
# JkRequestLogFormat set the request format
JkRequestLogFormat "%w %V %T"
# Send all grizzly/ requests to Grizzly
JkMount /grizzly/* worker1


The add in your /etc/apache2/worker.properties


# Define 1 real worker using ajp13
worker.list=worker1
# Set properties for worker1 (ajp13)
worker.worker1.type=ajp13
worker.worker1.host=localhost.localdomain
worker.worker1.port=8009
worker.worker1.lbfactor=50
worker.worker1.cachesize=10
worker.worker1.cache_timeout=600
worker.worker1.socket_keepalive=1
worker.worker1.socket_timeout=300

With the above, we are telling Apache to forward (via mod_jk) all requests starting with /grizzly to .... GrizzlyWebServer! How? Let's take the previous example and add support for mod_jk:

        GrizzlyWebServer ws = new GrizzlyWebServer("/var/www");
        try{
            ws.addGrizzlyAdapter(new GrizzlyAdapter(){  
                
                public void service(GrizzlyRequest request, GrizzlyResponse response){
                    try {
                        response.getWriter().println("Grizzly is so cool!!!");
                    } catch (IOException ex) {                        
                    }
                }
            });
            ws.enableProtocol(PROTOCOL.AJP);
            ws.start();
        } catch (IOException ex){
            // Something when wrong.
        }

Just compile, java -jar ...That's it! Now any blog talking about mod_jk clustering/load balancing configuration can be used with your GrizzlyAdapter. As an example, take a look at this one

For any questions, post them to users@grizzly.dev.java.net or tweet us here.

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