Chapter 26. Configure JGroups

JGroups is the underlying group communication library used to connect Red Hat JBoss Data Grid instances. For a full list of JGroups protocols supported in JBoss Data Grid, see Section A.1, “Supported JGroups Protocols”
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26.1. Configure Red Hat JBoss Data Grid Interface Binding (Remote Client-Server Mode)

26.1.1. Interfaces

Red Hat JBoss Data Grid allows users to specify an interface type rather than a specific (unknown) IP address.
  • link-local: Uses a 169.x.x.x or 254.x.x.x address. This suits the traffic within one box. 
    <interfaces>
    <interface name="link-local">
        <link-local-address/>
    </interface>
    <!-- Additional configuration elements here -->
</interfaces>
  • site-local: Uses a private IP address, for example 192.168.x.x. This prevents extra bandwidth charged from GoGrid, and similar providers. 
    <interfaces>
    <interface name="site-local">
        <site-local-address/>
    </interface>
    <!-- Additional configuration elements here -->
</interfaces>
  • global: Picks a public IP address. This should be avoided for replication traffic. 
    <interfaces>
    <interface name="global">
        <any-address/>
    </interface>
    <!-- Additional configuration elements here -->
</interfaces>
  • non-loopback: Uses the first address found on an active interface that is not a 127.x.x.x address. 
    <interfaces>
    <interface name="non-loopback">
        <not>
	    <loopback />
	</not>
    </interface>
</interfaces>
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26.1.2. Binding Sockets

Socket bindings provide a named the combination of interface and port. Sockets can be bound to the interface either individually or using a socket binding group.
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26.1.2.1. Binding a Single Socket Example

The following is an example depicting the use of JGroups interface socket binding to bind an individual socket using the socket-binding element.

Example 26.1. Socket Binding

<socket-binding name="jgroups-udp" <!-- Additional configuration elements here --> interface="site-local"/>
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26.1.2.2. Binding a Group of Sockets Example

The following is an example depicting the use of Groups interface socket bindings to bind a group, using the socket-binding-group element:

Example 26.2. Bind a Group

<socket-binding-group name="ha-sockets" default-interface="global"> 
	<!-- Additional configuration elements here -->
	<socket-binding name="jgroups-tcp" port="7600"/>
	<socket-binding name="jgroups-tcp-fd" port="57600"/>
	<!-- Additional configuration elements here -->
</socket-binding-group>
The two sample socket bindings in the example are bound to the same default-interface (global), therefore the interface attribute does not need to be specified.
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26.1.3. Configure JGroups Socket Binding

Each JGroups stack, configured in the JGroups subsystem, uses a specific socket binding. Set up the socket binding as follows:

Example 26.3. JGroups UDP Socket Binding Configuration

The following example uses UDP to automatically detect additional nodes on the network: 
<subsystem xmlns="urn:jboss:domain:jgroups:1.2" default-stack="udp">
    <stack name="udp">
        <transport type="UDP" socket-binding="jgroups-udp">
            <!-- Additional configuration elements here -->
        </transport>
        <!-- rest of protocols -->
    </stack>
</subsystem>

Example 26.4. JGroups TCP Socket Binding Configuration

The following example uses TCP to establish direct communication between two clusters nodes. In the example below node1 is located at 192.168.1.2:7600, and node2 is located at 192.168.1.3:7600. The port in use will be defined by the jgroups-tcp property in the socket-binding section. 
<subsystem xmlns="urn:infinispan:server:jgroups:6.1" default-stack="tcp">
    <stack name="tcp">
        <transport type="TCP" socket-binding="jgroups-tcp"/>
        <protocol type="TCPPING">
            <property name="initial_hosts">192.168.1.2[7600],192.168.1.3[7600]</property>
            <property name="num_initial_members">2</property>
            <property name="port_range">0</property>
            <property name="timeout">2000</property>
        </protocol>
        <protocol type="MERGE3"/>
        <protocol type="FD_SOCK" socket-binding="jgroups-tcp-fd"/>
        <protocol type="FD_ALL"/>
        <protocol type="VERIFY_SUSPECT"/>
        <protocol type="pbcast.NAKACK2">
            <property name="use_mcast_xmit">false</property>
        </protocol>
        <protocol type="UNICAST3"/>
        <protocol type="pbcast.STABLE"/>
        <protocol type="pbcast.GMS"/>
        <protocol type="MFC"/>
        <protocol type="FRAG2"/>
    </stack>
</subsystem>
The decision of UDP vs TCP must be made in each environment. By default JGroups uses UDP, as it allows for dynamic detection of clustered members and scales better in larger clusters due to a smaller network footprint. In addition, when using UDP only one packet per cluster is required, as multicast packets are received by all subscribers to the multicast address; however, in environments where multicast traffic is prohibited, or if UDP traffic can not reach the remote cluster nodes, such as when cluster members are on separate VLANs, TCP traffic can be used to create a cluster.

Important

When using UDP as the JGroups transport, the socket binding has to specify the regular (unicast) port, multicast address, and multicast port.
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