GT 3.9.5 WS MDS WebMDS (Tech Preview): User's Guide

Introduction

WebMDS is a web-based interface for viewing formatted information about Grid resources. In the simplest instance, a web server administrator creates an HTML link that causes the WebMDS server to collect and format information that is presented to the user. Users can also use web forms to specify parameters that control what information is collected and how it's presented.

Command-line tools

There is no end-user command-line tool for WebMDS.

Tool description

The command-line tool webmds-create-context-file is used to create Tomcat configuration files needed to deploy WebMDS.

Command syntax

webmds-create-context-file [-f] tomcat_context_file

The tomcat_context_file argument is the location of the Tomcat configuration file defining the WebMDS context; in a default Tomcat installation, the location of this file will be $CATALINA_HOME/conf/Catalina/localhost.

By default, webmds-create-context-file will not overwrite an existing context file; the -f option is used to force webmds-create-context-file to overwrite an existing file.

Note: webmds-create-context-file is found in $GLOBUS_LOCATION/lib/webmds/bin

Example 
    $GLOBUS_LOCATION/lib/webmds/bin/webmds-create-context-file -f \
         $CATALINA_HOME/conf/Catalina/localhost

Limitations

Changes to the Tomcat context do not take effect until Tomcat is restarted or reloaded.

Graphical user interfaces

Overview of the purpose and functionality of the GUI

The WebMDS GUI is a web-based interface for browsing formatted XML data, such as the results of resource property queries on a grid service.

Command and options

WebMDS can be accessed using any web browser. In a default WebMDS installation, the URL http://hostname:port/webmds corresponds to the top-level WebMDS web page. This page includes a link to a WebMDS invocation that provides summary information (with links to detailed information) about a locally-running MDS Index server. It also contains a link to a page of sample web forms demonstrating other uses of WebMDS.

Customizing the web forms used to access WebMDS

The WebMDS servlet is located at http://your-tomcat-host:your-tomcat-port/webmds/webmds. It takes the following arguments:
info The name of the XML source that will be used to collect the raw XML data. XML sources are defined by files in $GLOBUS_LOCATION/lib/webmds/conf. This argument must be specified.
xsl The name of the XML source that will provide the XSL transform. XML sources are defined by files in $GLOBUS_LOCATION/lib/webmds/conf. If this argument is not specified, the WebMDS servlet will display raw, untransformed XML.
xmlSource.info_name.param.source_specific_options Any additional options recognized by the info_name XML source (info_name must be the value of the info argument for this request). Source-specific options are discussed in the next section.
xmlSource.xsl_name.param.source_specific_options Any additional options recognized by the xsl_name XML source (xsl_name must be the value of the xsl argument for this request). Source-specific options are discussed in the next section.

Limitations

Error conditions (such as typographical errors in resource property names) are presented as stack traces, rather than user-friendly error messages.

Troubleshooting

The commonly-used WebMDS plugins do resource property queries; the Globus Toolkit wsrf-query can be used to determine whether the desired information is available directly from the resource.