The Single Image System in SEASnet

SEASnet has been working on a project to enhance the "Single Image System" in SEASnet. The primary goal of the project is to expand the boundaries of the existing user computing environment to include all of the systems in a network cluster without altering the user's perception that all work is occurring at the local system level.

The project is to develop a set of utilities that enhance the concept of the network as a single system within the School of Engineering and Applied Science (SEAS) at UCLA.

The tools provided are based upon modifications to existing network utilities commonly found on Unix systems and are easily implemented in a heterogeneous network environment.

Following are the basic features of the proposed implementation:

1. A global user file system utilizing NFS.
2. A unique home directories for each machine type for each user with simple subdirectory access for other home directories from the current machine type home directory.
3. The ability to treat the entire cluster of systems as a single set of machines and additionally allocate individual machines within the cluster into intersecting subsets for purposes of login and process execution.
4. Centralized password services and utilities for adding and maintaining accounts for the cluster and all subsets.
5. Telnet and rlogin access to the least loaded site within a requested cluster.
6. Network authentication upon initial login connection. Further connection (login, rsh, remote process execution) within the cluster are authenticated without additional password requests.
7. Transparent remote execution of processes in a heterogeneous network.
8. Individual process execution on least loaded sites within the cluster.

The first five items listed above have already been implemented within the SEASnet environment. Items six and seven are the critical items that will allow the entire SEASnet cluster of machines to be treated as a single system with a high degree of process transparency across the cluster. Item number eight will increase perceived performance for applications that require substantial amounts of CPU and clock time to complete.

The completed project will enable users to initiate a login session to a subset of the entire cluster and automatically be connected to the least loaded system within that subset. Upon authentication the user is automatically authenticated for the entire cluster and all subsets where the users's account is valid. Further remote connections for either logins or individual processes are automatically authenticated by the system.

Under the network system, users will initiate standard system or user application processes without modification to the application or the command syntax. The process will run either locally or remotely dependent upon configuration parameters determined by the system administrator or the user. In all cases, the user's present terminal or window functions as the controlling tty for the process.

For example, an individual with a current session on a RISC System 6000 may initiate standard system commands such as "who" or "ls" that will execute on the local system. However, if another application such as "Mentor Graphics", currently licensed and available only on a Sun system, is requested, the program will automatcically execute on the system where the program is available without any indication from the user's perspective that the process was unavailable locally and is running remotely.

It is believed that the development of the described system will enable SEASnet to make more effective use of all computing resources within the network environment. It will minimize the administrative effort required to distribute computing loads across systems within the SEASnet environment and increase the perceived performance and availability of certain applications to SEAS' users.