Remote Control - Using the Control Program

Using the Control Program

The Remote Control GUI tool is ideal for setting up, diagnosing, upgrading, debugging, starting, and stopping OODT server processes running under a Server Manager at a remote site. Its graphic interface, however, prevents it from being run from cron jobs or from remote shells. Further, it doesn't enable you run operations at every Server Manager.

The Control program, on the other hand, is a command-line oriented program that operates on the entire network of OODT servers at once.

Describing the Network

The Control program uses a Network Description in order to understand and operate on a network of Server Managers. The Network Description is an XML document listing Server Managers, processes expected to run at each server manager, and sets of processes that constitute an operational unit.

The PDS and EDRN software installations already have Network Descriptions:

Installation: PDS

Host: starbrite.jpl.nasa.gov

File: /usr/local/pds/etc/network.xml

Installation: EDRN

Host: ginger.fhcrc.org

File: /usr/local/edrn/etc/network.xml

Creating and Maintaining a Network Description

The Network Description is a relatively simple XML Document Type Definition (DTD). This section describes the elements and attributes of the DTD.

The Network Description identifies each Server Manager available, then each process in the entire netw ork, then named sets of processes. Different process sets serve different needs; for example, there could be an operations set and a development set. One set is always the default set that the Control program uses if no set is specified to it in its command line arguments.

Identifying the Document Type

When creating a new Network Description, list the document type's Formal Public Identifier (FPI) and System Identifier as follows:

      
     <
   
     !DOCTYPE network PUBLIC "-//JPL//DTD EDA Server Network 1.0.0//EN"
   
     
	    "http://oodt.jpl.nasa.gov/dtd/network.dtd"
   
     >

The EDM software will automatically use the FPI to locate a local copy of the network.dtd file, if properly configured.

The Network

The network element identifies the entire network and must be the document element in the Network Description. Its attributes identify default values for usernames, passwords, and proxy servers needed to access various Server Managers in the network.

Attributes

default: This optional attribute identifies the name of the process set that is the default one on which to operate. If not specified, the first process set in the Network Description becomes the default.
username: This optional attribute names the default user name to use to connect to a Server Manager in the network. If a Server Manager has no username attribute, this one is used.
password: This optional attribute lists the default password to try to use when connecting to a Server Manager.
proxy: This attribute names the URL to the XML-RP C proxy server to use when connecting to a Server Manager. If a Server Manager entry lists its own proxy, it is used instead. If not, then this attribute is used. If this attribute isn't specified, then no proxy will be used.
Note: Specifying the proxy attribute on the network element means a proxy will always be used to connect to every Server Manager, since there is currently no way for a Server Manager entry in the Network Description to identify that it needs no proxy.

Example:

      
     <
   
     ?xml version="1.0" encoding="UTF-8"?
   
     >
   
     
	    
   
     <
   
     network
   
     
	    username="Administrator"
   
     
	    password="s3cr3t.p455w0rd"
   
     
	    proxy="http://gateway.big.com:7575/"
   
     
	    /
   
     >

This (useless) Network Description names a network with no Server Managers, processes, or process sets.

Server Managers

Zero or more server elements should appear below the network element. Each server identifies a Server Manager, how to login to it, and how it should be labelled on user interfaces.

Attributes

id: This required attribute identifies the Server Manager within the Network Description.
url: This required attribute gives the URL to the Server Manager.
username: This optional attribute names the user name to use to connect to the server. If not given, the username of the network is used instead.
password: This optional attribute lists the password that authenticates the use r. If not given, the password of the network is used instead.
proxy: This attribute names the URL to the XML-RPC proxy server to use when connecting to this server. If not given and there's no proxy attribute in the network element, then no a direct connection is made. Otherwise, the named proxy is used.

Child Elements

label: Zero or more labels identify the server in human readable terms. You can also specify the xml:lang attribute for language-specific names of the server. If there are no labels, the default is its id .

Invoking the Control Program

The Control program is a Java program, and therefore is invoked by starting the Java virtual machine (JVM) on the Control program's class name. You'll also need to specify the optional package directory of the class so that the JVM can find the class and the other classes on which it depends.

If invoked with no arguments, the program prints a usage message:

      
     % 
   
    
      
     java -Djava.ext.dirs=
   
    
      
     installDir
   
    
   
     /lib jpl.eda.server.Control

The usage message tells you the operations you can perform on the network of server managers.