Process Management Working Group Process Management “Meatball” Dallas November 28, 2001

2 Subcomponents Process/Job management –What it includes and what it doesn’t include –Current status of interface definition –Demo Monitoring –Examples –Relationship to process management Checkpointing –Is this a component? –Relationship to process management

Usage Reports User DB AccountingScheduler Process Manager System Monitor Queue Manager Checkpoint/ Restart Data Migration Meta Scheduler Node Configuration & Build Manager Meta Monitor Meta Manager Resource Allocation management Application Environment High Performance Communication & I/O Access control Security manager File System Interacts with all components User utilities One Meatball

4 Process Manager Responsibilities Starts processes (and therefore knows hosts and pids) Delivers arguments, environment, limits –(between fork and exec) Starts other processes that need to know pids –Monitoring (e.g. Paradyn) –Debugging (e.g. TotalView) –Other (e.g. Myrinet monitor) Kills jobs Signals processes –May be part of checkpointing Report on job start/termination Provides return codes (job/process) Handles stdio as directed Service application runtime layer –Implements PMI (put/get/barrier/spawn, others as discovered)

5 P.M. Non-Responsibilities Policy Real-Time resource usage monitoring

6 Process Manager Component Interface to Other Components Defined (I.e. proposed XML schema exists) –Start-job Start-job response –Kill-job Kill-job response To do –Suspend-job, resume-job –Signal-job in general –Asynchronous notifications Job started Job terminated Others

7 The Process Manager Interface to Application Libraries A Prototype: PMI (formerly known as BNR) Used by application libraries (e.g. MPI implementations, UPC implementations, common runtime systems for multiple languages and libraries) Provided by process managers Simple and general –Find out rank and size –Put and get into keyval space –Barrier –Spawn Currently used by MPICH, provided by MPD

8 The Chiba City Testbed Dedicated to scalability research in computer science rather than to applications Currently 256 dual-processor nodes Designed to promote experimentation with system software SciDAC projects can get accounts: –Web form at –Specify SCIDAC as Project Group –Specify closest Argonne SciDAC person as contact (Rusty or Narayan for SSS) Future plans –1000 nodes, 8000 virtual nodes Vmware User-mode Linux

9 A Demo Start Service Directory component Start Process Manager component –It registers itself with Service Directory Start Proto-scheduler component –It queries Service Directory for access location (host,port) of process manager –It sends job-start requests from hard-coded queue to process manager –Process manager runs parallel jobs All components communicate using XML –Use XML schema for process-manager requests, responses –Prototypes written in Python with built-in XML parser

10 A Modest Proposal Multiple Wire Protocols are allowed. Components declare a WP associated with a port when they register with the service directory. (They can register multiple ports.) Other components learn the WP associated with a port when they find out the port. The default protocol is the “basic” protocol. –TCP –A message consists of a complete XML document –After sending, the sender does shutdown on the socket, providing EOF to the receiver to signal the end of the message, but leaving the socket half-open to receive the response. All components are required to support at least the basic protocol.

11 Advantages Something easy to start with No “framing problem” No other software required Does not preclude other protocols, which include security, streaming, etc. Can be used to bootstrap switches of protocol.