Mobile Work Environment for Grid Users

In the paper we aim to describe the project developing the Migrating Desktop infrastructure for the mobile users in a simple way. We also focus on the development testbed, which is prepared for the testing purposes of the runtime environment. This functionality refers to the work environment of the users, which change their location very often. The mobility term refers to the users, which use the open session without moveing themselves during the on-line connection. It means, that the user can move between sessions only. The consideration of the mobile user with the active open connection to the Internet is a well-known problem and many other projects respecting this functionality have been started. However this feature is not the point of our project. This work is done under the EU CrossGrid project IST-2001-32243 [1]. In the paper we present the functionality, the architecture and the main components of the core of developed system. It consists of the Application Portal Server, the Desktop Portal Server, the Roaming Access Server, the Security component (the Authentication and the Authorisation), the User Profile Manager. For the grid enabled applications the new idea of application container framework has been investigated. The grid aplication is represented by a kind of wizard equipped with the demanded Application Plugin. The grid application developers should support such plugin. We use also advanced technology based on the Web Services. We use them within the interfaces of the Roaming Access Server (RAS): LDAP manager, the Job Submission, the Session Manager, the Benchmarks and File operation services [4]. The user front-end is implemented as the fat client: advanced graphical java based application. The user interface called the Migrating Desktop, or grid desktop is a very useful environment that accomplishes an integrated set of services and real applications, which could be run on the grid. The users can restore their environment in every place where the network access is possible. The authors are interested in the assimilation of the grid desktop with the system desktop as much as possible. The main core of the mobile work environment is the Roaming Access. The Roaming Access Server (RAS) infrastructure is the set of modules and their interconnections hidden ‘behind’ the user interface. What is needed for tomorrow is the proper remote and individual access to the resources, independently of the original location of the user. So far, the way of system usage has been looking in the following way: the user sits at his workstation and works with his favourite local applications. From time to time he launches a web browser and plays with it. An advanced user wants to log in to the remote host and run his, let us say, UNIX application. After computations, he somehow downloads output files and accomplishes investigation of the results. Some of the experienced users use protocols for emulating the remote environment in the graphical manner for working with their files. The user is able to use many systems with different resources and different security policies, sharing the resources among other people. The Migrating Desktop will create a transparent user work environment, independently of the system version and hardware. The Migrating Desktop will allow the user to access the grid resources from other computers like i.e. laptops, or internet-caffee workstations. The Roaming Access and the Migrating Desktop features will not support ? moving users“ . It means that no special mechanisms to access the grid resources via mobile phones, PDAs (such as palmtops, organisers, etc.) will be considered within the confines of the given project. The support of such hardware needs an extra environmental work respecting the binary incompatibility with the widelly used personal computers equipped with the J2RE 1.4.1 or higher. It will allow to run applications, manage data files, store personal settings (configuration definitions that characterise e.g. links to the user data files, links to applications, access to application portals and/or specialised infrastructure, as well as windows settings), independently of the localisation or the terminal type. The Application Plugin and the Container in general view will suport the interface to the application specific inputs and output. This will allow preparing the portal framework, which is independent of the application, so that we could easily extend it and add the other applications. The Application Container is a framework for the Application Plugin. It is a frame in which the application plugin will appear. Giving the ApplicationContainer API that can be accessed from the plugin we support a very advanced tool for the general use. It can control the Application Plugin by the signal catching and forwarding them to the lower layer and invoking the appropriate actions. The Application Plugin is a content of the Application Container. It should provide and implement two panels of the Job Submission wizard: arguments and job output. It should be able to visualise the output of the grid application. Application plugin must implement appropriate plugin interface. The Application Plugin can be a java applet and should implement all necessary interfaces to the Container. The Migrating Desktop provides a wizard that user can use to specify the job details. This wizard will simplify process of specifying parameters and limits, suggesting user defaults or last used parameters. It will consist of several panels. Two panels are reserved for the application specific plugin – the Argument Panel and the Job Output panels. As a bottom line of the middleware we use the Globus toolkit. These facilities give us an important functionality like security policy, simple remote operations, user account mapping, etc. The CrossGrid project is not the only star on the grid firmament but one of them and it cannot exist without any influence from the surroundings. Some elements used in this work come from the DataGrid project [2] like the idea of the grid interactive job submission and the Virtual Organisation (VO) paradigm. Fig. 1: The Migrating Desktop layout – example. The graphical interface (see Fig. 1) between the user and the Desktop Portal Server application will be in the form of a user desktop – similar to MS Windows or Linux systems desktops. The new desktop will be independent of the system desktop. It means that there will be no direct interaction between grid and system desktops, like copying files using the drag and drop mechanism. The main goal of the extra desktop is to make it possible for the grid user to work with local and grid applications without any difficulties. Much effort will be utilised in Single Sign-On feature that has been widely spoken to be the most important feature in the upcoming grid technology. There are too many resources with an additional authorisation procedure; that is why we want to simplify the user access. Delegation of the credentials is the way we want to follow. The Globus Security Infrastructure (GSI) [3] will be used as the public key infrastructure for our purposes. We also focus on the work with interactive applications. The novelty of the development consists in the grid interactive application utilisation within the migrating users’ environment. There are a lot of problems with the interaction in the grid environment. Some sort of solution has been proposed. When the user submits a Grid Interactive Job (GIJ) he needs the allocation of grid resources throughout his “interactive session”. During the whole session a bi-directional channel is opened between the user client and the application programme on remote machine. The entire job input and output streams are exchanged with the user client via this channel: the user sends input data to the job and receives output results and error messages. Details on the mechanism we foresee to manage GIJ’s are in the full paper. A very important feature in interactive environments is the ability to recovery from unexpected failures of e.g. workstation. There is no problem in case of batch jobs, but interactive applications need to be equipped with an extra functionality. It would be better not to rewrite the existing application codes respecting the new grid paradigm. However, it should be considerable to build the additional linkable library for managing grid interactive session management. The mentioned functionality is developed within the CrossGrid project [5] and will be released the first time in February 2003.