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# Configuring `inetd` to Launch `rmid`

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On the Solaris Operating System (Solaris OS), the Internet services daemon `inetd` provides an alternative to starting up services at system boot time. This daemon, a server process for Internet standard services, can be configured to start services on demand. For details on the Internet services daemon, see the Solaris OS `inetd(1M)` man page.

As of the J2SE(tm) 5.0 release, `inetd` can be configured to start the Java RMI activation daemon `rmid` on demand. In this case, `rmid` does not need to be started up at boot time or started up manually. Instead, `rmid` will be started when a client attempts to connect to it, such as in order to activate an object.

Note: If restartable services are registered with `rmid`, `rmid` should be started at system boot type (not by `inetd`) so that the restartable services are always running when the system is up.

To configure `inetd` to launch `rmid`, you will need to add an entry to each of two configuration files that `inetd` uses, `/etc/inetd.conf` and `/etc/services`. Editing these files requires root access to the machine that `rmid` will run on.

After `inetd` has been reconfigured, you should test your configuration to make sure that it works properly.

This tutorial has the following steps:

> - Configure `/etc/inetd.conf`
> - Configure `/etc/services`
> - Force `inetd` to read its new configuration
> - Test your configuration

## Configure `/etc/inetd.conf`

> The `/etc/inetd.conf` configuration file contains entries for the services to be launched when `inetd` receives a request over a socket. For details on the format of this configuration file see the Solaris OS `inetd.conf(4)` man page.

> To configure `inetd` to launch `rmid`, add the following entry to the `/etc/inetd.conf` configuration file (requires root access to the machine):

> >     rmid stream tcp wait nobody jreHome/bin/rmid  \
> >          rmid -log logDir/rmid.log rmidOptions

> where jreHome is a path to the installed JRE, logDir is the directory for the log file, and rmidOptions is any other options for `rmid` (for example, property initializations). When `rmid` is launched by `inetd` the `-log` option must be specified, and the `-port` option must not be specified, since the port is derived from the `/etc/services` configuration.

> If `rmid` needs to be run as a user other than `nobody`, replace `nobody` above with the user ID under which `rmid` should run.

## Configure `/etc/services`

> Next, `rmid` needs to be listed as a service in the `/etc/services` configuration file. For details on the format of this configuration file see the Solaris OS `services(4)` man page.

> To list `rmid` as a service, add the following entry to the `/etc/services` configuration file (requires root access to the machine):

> >     rmid        port/tcp

> where port is the port number for the `ActivationSystem` and the `Activator` remote objects that `rmid` exports. This port number is typically 1098, but another port number can be used as long as the clients and activatable services define the system property `java.rmi.activation.port` to that port.

## Force `inetd` to read its new configuration

> Now that the configuration has been modified, `inetd` needs to read the new configuration so that it can listen on the appropriate ports for the services that are configured.

> But first, it is important to make sure that `rmid` is not already running. To do this, run the following command:

> >     % ps -ef | grep rmid

> If the above command does not print out the information for a running `rmid` process, then `rmid` is not running. If it does, then you will need to shut down `rmid` first before continuing.

> Next, `inetd` needs to read its new configuration. To force `inetd` to reread its configuration, the running `inetd` process must be sent a hangup signal. First, find the process ID for the running `inetd` process by running the following command:

> >     % ps -ef | grep inetd

> which will print out something like this:

> >     root   171     1  0   Sep 30 ?        0:02 /usr/sbin/inetd -s

> In this example, the process ID for `inetd` is `171`. Now, the `inetd` process can be sent a hangup signal by running the following command and supplying the process ID (requires root access):

> >     % kill -HUP 171

> Now, `inetd` is all set to launch `rmid` when a program attempts to connect to the port configured above.

## Test your configuration

> To test that `inetd` is configured properly, you can run a simple program that looks up the `ActivationSystem` which will, in turn, cause `inetd` to launch `rmid` if the configuration is correct.

> The following is a simple program to look up the `ActivationSystem` on a port, supplied as the value of the `java.rmi.activation.port` system property:

> >     package example.inetd;

> >     import java.rmi.activation.ActivationSystem;
> >     import java.rmi.activation.ActivationGroup;

> >     public class GetActivationSystem {

> >         public static void main(String[] args) throws Exception {

> >     	ActivationSystem system = ActivationGroup.getSystem();
> >     	System.err.println("ActivationSystem = " + system);
> >         }
> >     }

> Compile and run this program as follows:

> >     % javac -d classDir GetActivationSystem.java
> >     % java -classpath classDir -Djava.rmi.activation.port=port
> >     example.inetd.GetActivationSystem

> where classDir is the class path for this example class, and port is the port for the `ActivationSystem` configured for `rmid` in the `/etc/services` file.

> If the program prints out the `ActivationSystem` successfully then `rmid` was launched by `inetd`.

> If the program either hangs or prints an exception trace, check the output file produced by `rmid`. When `rmid` is launched by `inetd`, any output written to `System.err` is written to a file located in the directory specified by the property `java.io.tmpdir`, typically `/var/tmp` on the Solaris OS. The output file is prefixed with "rmid-err" and has the suffix of ".tmp". The file name also contains other characters (typically numbers) in between to keep the file name unique.

> If `rmid` starts up successfully from `inetd`, the output file should contain text similar to the following (with no warning or error messages):

> >     Tue Sep 30 13:07:38 EDT 2003
> >     rmid startup with inherited channel: sun.nio.ch.ServerSocketChannelImpl[/129.148.70.120:1098]

> If the file does not exist, the above text is not in the file, or additional error output is in the file, then recheck the configuration. Upon changing the `inetd` configuration, remember to send `inetd` a hangup signal so that it rereads its altered configuration, and remember to terminate any `rmid` process started from the previous attempt before continuing.

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