Red Hat JBoss Enterprise Application Platform Administration I

A server is a logical runtime instance of Red Hat JBoss Enterprise Application Platform (JBoss EAP) running within a managed domain. A server belongs to a server group, even if the group only contains a single server. Individual servers are managed by the respective host controllers. The host controllers communicate with the domain controller, and ensure that all the servers within a managed domain have the same configuration.

Each server belongs to a unique server group and runs within a host. A host can run multiple servers simultaneously by using the JBoss EAP provided concept of a port offset to ensure that there are no network port or socket clashes at runtime.

Servers are configured in the host.xml file on the individual host controllers, which run on a physical or virtual machine.

Servers in a managed domain are defined in the <servers> section of host.xml on each host controller. You can use the child element <server> within the <servers> parent element to define a server. For example:

  <servers>
    <server name="serverA" group="main-server-group">  
        <socket-bindings socket-binding-group="standard-sockets"/> 
    </server>
    <server name="serverB" group="other-server-group" auto-start="true"> 
        <jvm name="default">
           ...
        </jvm>
        <socket-bindings socket-binding-group="standard-sockets" port-offset="350"> 
    </server>
</servers>

You can create the servers in a managed domain in the Hosts section under the Runtime tab of the management console.

Figure 5.11: Runtime view

To add a new server, you must provide the following three key attributes:

Figure 5.12: Creating a new server

To remove a server from a host, ensure that the server is stopped.

Figure 5.13: Server options - Remove

Individual servers can be started, stopped, restarted, reloaded, and suspended by clicking View drop-down menu next to the server in the Hosts section under the Runtime tab of the management console.

You can create and manage servers by using the JBoss EAP management CLI. The advantage of this approach is that the steps to create and manage the servers can be scripted as part of an automated workflow and it is faster to create multiple servers in batched mode. This approach also has the option of atomically committing or rolling back multiple steps in batch mode, thereby ensuring the integrity of the host.xml configuration file in case of an error during execution of the CLI commands.

You configure the servers in the /host namespace of a managed domain. There are commands to create, view, start, stop, restart, reload, suspend, and remove servers under this namespace. To add a new server, run the following command:

[domain@workstation:9990 /] /host=host2/server-config=serverA:add\
(auto-start=true,group=Group1,socket-binding-port-offset=100)
{
    "outcome" => "success",
    "result" => {
        ....
    }
}

To start a single server, run the following command:

[domain@workstation:9990 /] /host=host2/server-config=serverA:start
{
    "outcome" => "success",
    "result" => "STARTING"
}

To stop a single server, run the following command:

[domain@workstation:9990 /] /host=host2/server-config=serverA:stop
{
    "outcome" => "success",
    "result" => "STOPPING"
}

All the servers in a server group can be started by running the following command:

[domain@workstation:9990 /] /server-group=Group1:start-servers(blocking=true)
{
    "outcome" => "success",
    ...
}

Similarly, to stop all the servers in a server group, run the following command:

[domain@workstation:9990 /] /server-group=Group1:stop-servers(blocking=true)
{
    "outcome" => "success",
    "result" => undefined,
    "server-groups" => undefined
}

To remove a server, you must first ensure that the server is stopped. To remove the server, run the following command:

[domain@workstation:9990 /] /host=host2/server-config=serverA:remove()
{
    "outcome" => "success",
    ...
}

In JBoss EAP, you can suspend a server by using the suspend operation. Any server in a suspended mode does not accept new requests from any client until the server is resumed. A suspended server can begin serving requests immediately by running the resume operation.

You can use the graceful shut down operation. A graceful shut down is different from an ordinary shut down because the server is suspended before shutting down. To invoke this behavior you must pass a timeout parameter to the shutdown, stop, or stop-servers operations. The server waits until the timeout for all requests is finished before shutting down.

You can also gracefully shut down a host controller from the management CLI. To shutdown a host controller, first ensure that all the servers running on this host are stopped and then run the following command:

[domain@workstation:9990 /] /host=host2:shutdown(timeout=1000)
{
    "outcome" => "success",
    "result" => undefined
}

You can to gracefully shut down the domain controller from the management CLI. To shutdown a primary domain controller, run the following command:

[domain@workstation:9990 /] /host=primary:shutdown(timeout=1000)
{
{"outcome" => "success"}
[domain@localhost:9990 /]
The controller has closed the connection.
[disconnected /]
}