An existing LAM session, initiated by lamboot(1), can be enlarged to
include more nodes with
lamgrow .
One new node is added for each invocation.
At a minimum, the host name that will run the new node is given on
the command line.
If a different userid is required to access the host, it is specified
with the -u option.
It can be useful to update the original boot schema used by lamboot(1)
with the new node added by
lamgrow .
The -c option specifies a boot schema filename and causes
lamgrow
to append the host name.
The updated boot schema is ready to be used by wipe(1) to terminate
the extended LAM session.
New nodes added by
lamgrow
will not be cleaned up by wipe(1) if the original boot schema is used.
They can be terminated individually, as always, with tkill(1).
The new node can be assigned any unused, non-negative identifier.
If no identifier is specified, the highest node identifier in the
current LAM session plus one is used.
Note that lamboot(1) always assigns node identifiers consecutively from 0.
lamgrow
can be run from any node.
As a LAM command program it must be run from a node in the existing
LAM session.
It cannot be run from the intended new host.
Two invocations of
lamgrow
should not run concurrently and the command attempts to detect this situation.
There is no protection against specifying the name of host that is
already part of the user's existing LAM session.
This is not the proper use of
lamgrow .
Resource managers will be the most common user of
lamgrow .
When hosts become idle and a user has expressed a desire to the manager
that extra cycles should be exploited, the manager could invoke
lamgrow
and then launch the specified application process(es) on the new node.