Proposed changes to Host profiles

VisIt uses what is called a host profile to contain information about launching components on remote computers. Host profiles contain information related to a user's remote account, SSH properties, networking settings, parallel launch environment, etc. VisIt can use several host profiles for any given computer system, allowing the user to set up profiles for a serial engine, and multiple parallel engines with different properties (e.g. interactive vs. batch). Furthermore, VisIt can store host profiles for many computer systems into different system configurations so users can select which set of commonly used machines they will use when installing VisIt.

Issues

Host profiles are very good at setting up VisIt to run on various computer systems, however there are issues:

  • They can be difficult to set up. This is not necessarily the fault of host profiles; it is more related to a user's familiarity with the underlying parallel launch system
  • Host profiles are currently stored in the user's ~/.visit/config file, which can make them prone to loss if the user blows away his settings file.
  • A common problem occurs at LLNL when the method to launch a parallel job on a machine changes, and a user has saved settings effectively locking them into a static old host profile. This is currently handled release by release using code with in VisIt to "massage" the user's host profile values - pruning/tweaking them get things back on track. Any improvements to host profiles should definitely address this issue.(Per machine host profiles seem like a good solution here...)

Changes

An improved host profile system might have the following features:

  • Store the host profiles in a separate file apart from the settings in ~/.visit/config