Cheiron

When you see java.net.SocketExceptions related to multicast discovery it is likely that your interface is not properly configured. You can either disable your faulty network interface or you can configure Seven to use a specific interface, or group of interfaces. Configuration can take place at the service level but often it is more convenient to configure this at the container level, i.e. in the seven.xsc file you can find in the config directory.

Locate the discovery element in the seven.xsc file and at the top add a multicast-interfaces element, for each interface to be configured for multicast discovery add one interface-name element with the name of the NIC, you can also use the bind-address element to specify the IP address for the NIC. In case of configuring just one interface you end up with something like is shown below, note that eth0 is only illustrative:

    <discovery>
        <multicast-interfaces>
            <interface-name>eth0</interface-name>
        </multicast-interfaces>
    </discovery>

You can find out the name of your NIC on most OSes other than Windows with ifconfig -a or netstat -i. For Windows it is not that easy to find the adapter name to use for configuration purposes, but it seems that if you execute ipconfig /all the first ethernet adapter listed is named eth0, the second eth1, etc. For Seven 1.0 and higher during boot the environment settings will be logged and you should be able to extract the name of the NICs from the log file or the console.

This configuration should also be used to prevent from multicast discovery packets leaking to the wrong network.

Yes, as the embedded jar file server can't outlive the container instance and distributed objects are often used while their service has been destroyed, the container can work together with an external HTTP server for serving download jar files beyond the lifespan of a service. By using a dedicated web server such as Apache an extreme reliable environment can be created, this option is however not only limited to Apache, the only requirements are:

• web server must have access to the file system the services are installed on for a particular Seven instance;
• web server must support the Apache mod_rewrite module, this also allows you to have multiple Seven instances served by a single virtual host.

If the requirements above are met you can add to the seven.xsc file the codebase-prefix element, see XML Seven Configuration Documentation, and set that to a codebase annotation prefix. This URI prefix will be appended by the container with the OID of the service, a version number, and the 'main' download jar file for that service. The resulting URL will be used by Seven to annotate classes when they are marshalled. Through the use of the mod_rewrite module the web server will rewrite the requested URL to the URI of the physical download jar file on the local file system. This template contains the required configuration for the mod_rewrite module and can be used as a starting point.