Condor Technical Summary

Introduction to the Problem A common computing environment consists of many workstations connected together by a high speed local area network. These workstations have grown in power over the past several years, and if viewed as an aggregate they can represent a significant computing resource. However in many cases even though these workstations are owned by a single organization, they are dedicated to the exclusive use of individuals. In examining the usage patterns of the workstations, we find it useful to identify three "typical" types of users. "Type 1" users are individuals who mostly use their workstations for sending and receiving mail or preparing papers. Theoreticians and administrative people often fall into this category. We identify many software development people as "type 2" users. These people are frequently involved in the debugging cycle where they edit software, compile, then run it possibly using some kind of debugger. This cycle is repeated many times duri

Condor Technical Summary

Condor is a software package for executing long running "batch" type jobs on workstations which would otherwise be idle. Major features of Condor are automatic location and allocation of idle machines, and checkpointing and migration of processes. All of these features are achieved without any modifications to the UNIX kernel whatsoever. Also, users of Condor do not need to change their source programs to run with Condor, although such programs must be specially linked. The features of Condor for both users and workstation owners along with the limitations on the kinds of jobs which may be executed by Condor are described. The mechanisms behind our implementations of checkpointing and process migration are discussed in detail. Finally, the software which detects idle machines and allocates those machines to Condor users is described along with the techniques used to configure that software to meet the demands of a particular computing site or workstation owner. 1. Introduction to the ..

Dynamic Streams For Efficient Communications between Migrating Processes in a Cluster

International audienceThis paper presents a communication system designed to allow efficient process migration in a cluster. The proposed system is generic enough to allow the migration of any kind of stream: socket, pipe, char devices. Communicating processes using IP or Unix sockets are transparently migrated with our mechanisms and they can still efficiently communicate after migration. The designed communication system is implemented as part of Kerrighed, a single system image operating system for a cluster based on Linux. Preliminary performance results are presented