ASC Portal Users Guide

Introduction

The Astrophysics Simulation Collaboratory (ASC) project seeks to provide a web-based problem solving framework for the astrophysics community to harness computational Grids. In addition to the generic environment suitable for any application the ASC portal supplies a specialized framework for the Cactus Computational toolkit.

The Cactus computational toolkit provides a widely used software package for solving partial differential equations in 3D including Einsteins general relativistic wave equations. The modular design of the Cactus framework permits a diverse group of researchers to develop add-on software modules, termed ``thorns", to integrate additional physics or numerical solvers into the Cactus framework.

The ASC Portal is a Web-based application server that provides access to Grid services and resources such as high-performance computers, code repositories, information servers, etc, and maintains a database documenting the history of each user's interaction with the Grid. This document navigates the user from the starting point though the full range of interfaces that enable grid computing. The ASC Portal is available at: www.ascportal.org.

Contents

1. Getting started with the ASC Portal

2. Grid

   2.1 Credentials

   2.2 Resources

   2.3 Services

3. Cactus

   3.1 Demo

   3.2 Configuration

   3.3 Simulations

   3.4 Paramters

4. Utilities

   4.1 FTP

   4.2 GRAM

   4.3 LDAP

5. Preferences

6. Visualization

7. Conclusion

1.Getting started with the ASC Portal

In order to perform grid operations within a portal session, one retrieves a grid credential from the ASC organizational MyProxy server. In order to load a credential onto this server it is necessary to have MyProxy client software installed on the same system on which your grid certificate/key pair are stored. A grid certificate is used to have a single sign-on access to all of the grid-enabled machines on which you have accounts.

The Myproxy package provides a secure method for portal users to access resources with a limited proxy using the Globus Security Infrastructure (GSI). If the web server is broken into, only the time limited delegated credentials are compromised. The proxy gives you single sign-on capability. While your proxy is active, you can log into any Grid resource without re-entering your pass phrase. A proxy is loaded onto the ASC organizational MyProxy server by running the myproxy-init command:

This command will generate a grid proxy credential, and store that credential on the MyProxy server. Within an ASC Portal user session one retrieves this credential for authenticating to Grid sites, enabling the user to perform grid operations such as checking out source code, staging files and submitting jobs. The myproxy-init command will require you to enter the password you used to generate the private key of your default grid credential, and then to enter a new password for retrieving your grid credential at a later time. It is highly recommended you choose a password other than the one you used to generate the private key of your grid credential. The username is used when you create your ASC Portal credential and it is set by default as your username from the machine you are running the myproxy-init command.

The first time that you login to the portal you will need to use your default username and a corresponding proxy password. After this initial login, credential definitions can be adjusted to make use of a different username.

Upon logging in to the portal you see the current status, consisting of a description of the present user session and a list of your current user credentials. In the Main Menu on the left-hand side are the following options: "Home", "Grid", "Cactus", "Utilities", "Preferences", "Visualization" and "Help". In the subsequent sections of this document we present the full description of these portal components.