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JBoss AS 7.2

High Availability Guide

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This guide is still under development, check back soon!

Target Audience

Cluster Configuration

Group Configuration

Web Container

EJB Container

Remote client invocation in the cluster see EJB invocations from a remote client using JNDI article in the developer's guide.

The Clustered EJBs chapter explains in detail on how clustered EJBs work in AS7.

Load Balancing & Failover

Apache Httpd

The recommended front-end module is mod_cluster but mod_jk or mod_proxy could be used as in Tomcat or other AS version.

To use AJP define a ajp connector in the web subsystem like:

<subsystem xmlns="urn:jboss:domain:web:1.0">
            <connector name="http" protocol="HTTP/1.1" socket-binding="http"/>
            <connector name="ajp" protocol="AJP/1.3" socket-binding="ajp"/>

To the ajp in the in the socket-binding-group like:

<socket-binding-group name="standard-sockets" default-interface="public">
         ....
           <socket-binding name="http" port="8080"/>
           <socket-binding name="ajp" port="8009"/>
           <socket-binding name="https" port="8443"/>

Mod Cluster

The mod_cluster integration is done via the modcluster subsystem it requires mod_cluster-1.1.x.or mod_cluster-1.2.x (since 7.1.0)

The modcluster subsystem supports several operations: 

[standalone@localhost:9999 subsystem=modcluster] :read-operation-names
{
    "outcome" => "success",
    "result" => [
        "add",
        "add-custom-metric",
        "add-metric",
        "add-proxy",
        "disable",
        "disable-context",
        "enable",
        "enable-context",
        "list-proxies",
        "read-attribute",
        "read-children-names",
        "read-children-resources",
        "read-children-types",
        "read-operation-description",
        "read-operation-names",
        "read-proxies-configuration",
        "read-proxies-info",
        "read-resource",
        "read-resource-description",
        "refresh",
        "remove-custom-metric",
        "remove-metric",
        "remove-proxy",
        "reset",
        "stop",
        "stop-context",
        "validate-address",
        "write-attribute"
    ]
}
The operations specific to the modcluster subsystem are divided in 3 categories the ones that affects the configuration and require a restart of the subsystem, the one that just modify the behaviour temporarily and the ones that display information from the httpd part.

operations displaying httpd informations

There are 2 operations that display how Apache httpd sees the node:

read-proxies-configuration

Send a DUMP message to all Apache httpd the node is connected to and display the message received from Apache httpd. 

[standalone@localhost:9999 subsystem=modcluster] :read-proxies-configuration
{
    "outcome" => "success",
    "result" => [
        "neo3:6666",
        "balancer: [1] Name: mycluster Sticky: 1 [JSESSIONID]/[jsessionid] remove: 0 force: 1 Timeout: 0 Maxtry: 1
node: [1:1],Balancer: mycluster,JVMRoute: 498bb1f0-00d9-3436-a341-7f012bc2e7ec,Domain: [],Host: 127.0.0.1,Port: 8080,Type: http,flushpackets: 0,flushwait: 10,ping: 10,smax: 26,ttl: 60,timeout: 0
host: 1 [example.com] vhost: 1 node: 1
host: 2 [localhost] vhost: 1 node: 1
host: 3 [default-host] vhost: 1 node: 1
context: 1 [/myapp] vhost: 1 node: 1 status: 1
context: 2 [/] vhost: 1 node: 1 status: 1
",
        "jfcpc:6666",
        "balancer: [1] Name: mycluster Sticky: 1 [JSESSIONID]/[jsessionid] remove: 0 force: 1 Timeout: 0 maxAttempts: 1
node: [1:1],Balancer: mycluster,JVMRoute: 498bb1f0-00d9-3436-a341-7f012bc2e7ec,LBGroup: [],Host: 127.0.0.1,Port: 8080,Type: http,flushpackets: 0,flushwait: 10,ping: 10,smax: 26,ttl: 60,timeout: 0
host: 1 [default-host] vhost: 1 node: 1
host: 2 [localhost] vhost: 1 node: 1
host: 3 [example.com] vhost: 1 node: 1
context: 1 [/] vhost: 1 node: 1 status: 1
context: 2 [/myapp] vhost: 1 node: 1 status: 1
"
    ]
}
read-proxies-info

Send a INFO message to all Apache httpd the node is connected to and display the message received from Apache httpd. 

[standalone@localhost:9999 subsystem=modcluster] :read-proxies-info
{
    "outcome" => "success",
    "result" => [
        "neo3:6666",
        "Node: [1],Name: 498bb1f0-00d9-3436-a341-7f012bc2e7ec,Balancer: mycluster,Domain: ,Host: 127.0.0.1,Port: 8080,Type: http,Flushpackets: Off,Flushwait: 10000,Ping: 10000000,Smax: 26,Ttl: 60000000,Elected: 0,Read: 0,Transfered: 0,Connected: 0,Load: -1
Vhost: [1:1:1], Alias: example.com
Vhost: [1:1:2], Alias: localhost
Vhost: [1:1:3], Alias: default-host
Context: [1:1:1], Context: /myapp, Status: ENABLED
Context: [1:1:2], Context: /, Status: ENABLED
",
        "jfcpc:6666",
        "Node: [1],Name: 498bb1f0-00d9-3436-a341-7f012bc2e7ec,Balancer: mycluster,LBGroup: ,Host: 127.0.0.1,Port: 8080,Type: http,Flushpackets: Off,Flushwait: 10,Ping: 10,Smax: 26,Ttl: 60,Elected: 0,Read: 0,Transfered: 0,Connected: 0,Load: 1
Vhost: [1:1:1], Alias: default-host
Vhost: [1:1:2], Alias: localhost
Vhost: [1:1:3], Alias: example.com
Context: [1:1:1], Context: /, Status: ENABLED
Context: [1:1:2], Context: /myapp, Status: ENABLED
"
    ]
}
operations that handle the proxies the node is connected too

there are 3 operation that could be used to manipulate the list of Apache httpd the node is connected too.

list-proxies:

Displays the httpd that are connected to the node. The httpd could be discovered via the Advertise protocol or via the proxy-list attribute. 

[standalone@localhost:9999 subsystem=modcluster] :list-proxies
{
    "outcome" => "success",
    "result" => [
        "neo3:6666",
        "jfcpc:6666"
    ]
}
remove-proxy

Remove a proxy from the discovered proxies or  temporarily from the proxy-list attribute. 

[standalone@localhost:9999 subsystem=modcluster] :remove-proxy(host=jfcpc, port=6666)
{"outcome" => "success"}
proxy

Add a proxy to the discovered proxies or  temporarily to the proxy-list attribute. 

[standalone@localhost:9999 subsystem=modcluster] :add-proxy(host=jfcpc, port=6666)
{"outcome" => "success"}
Context related operations

Those operations allow to send context related commands to Apache httpd. They are send automatically when deploying or undeploying  webapps.

enable-context

Tell Apache httpd that the context is ready receive requests. 

[standalone@localhost:9999 subsystem=modcluster] :enable-context(context=/myapp, virtualhost=default-host)
{"outcome" => "success"}
disable-context

Tell Apache httpd that it shouldn't send new session requests to the context of the virtualhost. 

[standalone@localhost:9999 subsystem=modcluster] :disable-context(context=/myapp, virtualhost=default-host)
{"outcome" => "success"}
stop-context

Tell Apache httpd that it shouldn't send requests to the context of the virtualhost. 

[standalone@localhost:9999 subsystem=modcluster] :stop-context(context=/myapp, virtualhost=default-host, waittime=50)
{"outcome" => "success"}
Node related operations

Those operations are like the context operation but they apply to all webapps running on the node and operation that affect the whole node.

refresh

Refresh the node by sending a new CONFIG message to Apache httpd.

reset

reset the connection between Apache httpd and the node

Configuration

Metric configuration

There are 4 metric operations corresponding to add and remove load metrics to the dynamic-load-provider. Note that when nothing is defined a simple-load-provider is use with a fixed load factor of one. 

[standalone@localhost:9999 subsystem=modcluster] :read-resource(name=mod-cluster-config)
{
    "outcome" => "success",
    "result" => {"simple-load-provider" => {"factor" => "1"}}
}

that corresponds to the following configuration: 

<subsystem xmlns="urn:jboss:domain:modcluster:1.0">
            <mod-cluster-config>
                <simple-load-provider factor="1"/>
            </mod-cluster-config>
 </subsystem>
metric

Add a metric to the dynamic-load-provider, the dynamic-load-provider in configuration is created if needed. 

[standalone@localhost:9999 subsystem=modcluster] :add-metric(type=cpu)
{"outcome" => "success"}
[standalone@localhost:9999 subsystem=modcluster] :read-resource(name=mod-cluster-config)
{
    "outcome" => "success",
    "result" => {
        "dynamic-load-provider" => {
            "history" => 9,
            "decay" => 2,
            "load-metric" => [{
                "type" => "cpu"
            }]
        }
    }
}
remove-metric

Remove a metric from the dynamic-load-provider. 

[standalone@localhost:9999 subsystem=modcluster] :remove-metric(type=cpu)
{"outcome" => "success"}
custom-metric / remove-custom-metric

like the add-metric and remove-metric except they require a class parameter instead the type. Usually they needed additional properties which can be specified 

[standalone@localhost:9999 subsystem=modcluster] :add-custom-metric(class=myclass, property=[("pro1" => "value1"), ("pro2" => "value2")]
{"outcome" => "success"}

which corresponds the following in the xml configuration file: 

<subsystem xmlns="urn:jboss:domain:modcluster:1.0">
            <mod-cluster-config>
                <dynamic-load-provider history="9" decay="2">
                    <custom-load-metric class="myclass">
                        <property name="pro1" value="value1"/>
                        <property name="pro2" value="value2"/>
                    </custom-load-metric>
                </dynamic-load-provider>
            </mod-cluster-config>
</subsystem>
JVMRoute configuration

If you want to use your own JVM route instead of automatically generated one you can insert the following property: 

...
</extensions>
<system-properties>
   <property name="jboss.mod_cluster.jvmRoute" value="myJvmRoute"/>
</system-properties>
<management>
...

Messaging

JNDI

All JBoss AS 7 documentation

There are several guides in the JBoss Application Server 7 documentation series. This list gives an overview of each of the guides:

*Getting Started Guide - Explains how to download and start JBoss Application Server 7.
*Getting Started Developing Applications Guide - Talks you through developing your first applications on JBoss Application Server 7, and introduces you to JBoss Tools and how to deploy your applications.
*JavaEE 6 Tutorial - A Java EE 6 Tutorial.
*Admin Guide - Tells you how to configure and manage your JBoss Application Server 7 instances.
*Developer Guide - Contains concepts that you need to be aware of when developing applications for JBoss Application Server 7. Classloading is explained in depth.
*High Availability Guide - Reference guide for how to set up clustered JBoss Application Server 7 instances.
*Extending JBoss AS 7 - A guide to adding new functionality to JBoss Application Server 7.

JBoss.org Content Archive (Read Only), exported from JBoss Community Documentation Editor at 2020-03-13 13:28:30 UTC, last content change 2012-03-04 17:03:57 UTC.