1. Encouraging the Unexpected: Cluster Management for OS and Systems Research Ronan Cunniffe Brian Coghlan Europar’2000 31-AUG-2000

2. Trinity College Dublin; Page 2 The Problem You OS guys crashed our cluster !

3. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 3 The Desire Crashes may be illuminating ! OS research environment: may not be stable may be missing features Separate cluster per project: is inefficient is expensive Mmmm …. As clusters become more common, problem gets more acute

4. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 4 Existing vs MultiOS solutions can support any number of environments no assumptions about stability or good behaviour places great demands on network and remote disk all candidate environments must be there no easy way to add another environment assumes environments will not over-write others Partition the local disk (dual/multiple boot) Existing Solution OS #1 OS #2 OS #3 OS #1 OS #2 OS #3 OS #1 OS #2 OS #3 Time …. OS #2 OS #1 Time OS #1 out OS #2 in Import the environment each time (from remote disk) MultiOS Solution Time

5. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 5 MultiOS standard mechanism for diskless workstations alternate between management and user sessions How is it implemented? can run from a RAM disk advantages of a full OS + network-mounted filesystems new tools can be written as necessary Management software is Linux management software obtained over network this then loads user image to local disk user runs whatever environment is on the local disk MultiOS considers this a black box

6. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 6 Scheduling: exclusive reservations by individual researchers scheduler is a module, i.e. replaceable MultiOS could be control mechanism within larger framework Overall MultiOS architecture MultiOS Server Scheduler Image Server BOOTP Server Linux FS (MultiOS client) TFTP Server Reset network requires a separate reset network ! Console (WWW)

7. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 7 BOOTP & TFTP are not secure OS images are read-write accessible how to keep private key secret on commodity PCs ? the web server is not secure distributed denial-of-service attacks Security Five principal issues:

8. Europar’2000 31-AUG-2000 Trinity College Dublin; Page 8 for any number of different environments for any type of research see http://www.cs.tcd.ie/multios/ Summary MultiOS allows a cluster to be shared