jsh@usenix.org (06/04/90)
From: <jsh@usenix.org>
An Update on UNIX<=-Related Standards Activities
May 1990
USENIX Standards Watchdog Committee
Jeffrey S. Haemer, Report Editor
IEEE 1003.7: System Administration, Interoperability Subgroup
Jim R. Oldroyd <jr@inset.com> reports on the April 23-27 meeting in
Salt Lake City, UT:
POSIX has given P1003.7 a charter to define both command-line and
applications-programming interfaces for administering multiple,
networked machines from a central point. Most reports on this group
seem to focus on the group's object-oriented approach: the
administerable classes the group is defining, their attributes
(properties) and their operators. [Editor: Martin Kirk has promised
us a report on this. Watch for it soon.]
Sometimes overlooked in this object-oriented frenzy is another,
equally important, and perhaps more difficult goal of the group:
interoperability.
Imagine, for example, an administrator who wishes to execute an
operation on some fraction of nodes in a large, heterogeneous network
of POSIX systems. The administrator wants to be able to issue the
request once -- and at his or her own terminal. The system should
take care of determining which actual objects are affected and of
communicating the request to them.
How should this be done? The fact that today's networks are
heterogeneous means that it is not sufficient for vendors simply to
supply systems with a consistent set of administerable object classes.
Nor is it enough for vendors to define a consistent set of commands
and API names that operate on these classes. On top of this, there
has to be a consistent language for systems from different vendors to
communicate with each other in order to tell each other that changes
have to be made to some of the objects they are supporting.
The P1003.7 Interoperability subgroup is defining a standard protocol
for communication with remote objects.
Currently, we are trying to work out the protocol's requirements. The
protocol will have to support varied system-management philosophies.
__________
=> UNIX is a registered trademark of AT&T in the U.S. and other
countries.
May 1990 IEEEd1003.7:dSystem Administration, Interoperability Subgroup
- 2 -
Some operations, such as re-enabling all PostScript<= printers, should
be queued and executed independently for each target. Failure to
enable one printer does not mean that the other printers should remain
disabled. Others operations must be atomic over the domain, for
example, when adding a user to a set of machines, it is necessary to
confirm that a UID is available on all target machines before adding
the user to any machine.
Each of these problems saddles the protocol with a different
requirement. The former case could be handled by broadcasting an
instruction and collecting success or failure reports later; the
latter requires a two-phase commit, requesting confirmation that
successful completion is possible throughout the domain before
actually mandating the change.
Do we have to invent a new protocol from scratch? P1003.7 is actively
studying existing protocols, such as ISO's CMIP/CMIS and the Internet
SNMP. Both of these are existing protocols designed to manage objects
across multiple systems -- exactly as per P1003.7's needs. However,
both of these are actually designed to manage the network itself, and
it is not clear that they lend themselves to management of things like
users, printers and filesystems (etc.) properly. We hope to discover
whether some existing protocol will fill the bill in the next few
meetings.
The Interoperability subgroup of P1003.7 will continue work in this
area at our next meeting (Danvers, MA, July 16-20). If you are an
interested party, we want to hear from you.
__________
=> PostScript is a trademark of Adobe Systems, Inc.
May 1990 IEEEd1003.7:dSystem Administration, Interoperability Subgroup
Volume-Number: Volume 20, Number 22