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LAMBOOT(1)				    LAM TOOLS				       LAMBOOT(1)

       lamboot - Start a LAM multicomputer.

       lamboot [-bdhvxH] [<bhost>]

       -b      Assume local and remote shell are the same.  This means that only one remote shell
	       invocation is used to each node.  If -b is not used, two remote shell  invocations
	       are used to each node.

       -d      Turn on debugging output.  This implies -v.

       -h      Print the command help menu.

       -s      Close stdio on the local node.

       -v      Be verbose.

       -x      Run in fault tolerant mode.

       -H      Do not display the command header.

       The  lamboot  tool  starts  the LAM software on each of the machines specified in the boot
       schema, <bhost>.  The boot schema specifies the hostnames of nodes to be used in the  run-
       time  MPI  environment,	and optionally lists how may CPUs LAM may used on each node.  The
       user may wish to first run the recon(1) tool to verify that LAM can be started.

       Starting LAM is a three step procedure.	In the first step, hboot(1) is invoked on each of
       the  specified  machines.   Then each machine allocates a dynamic port and communicates it
       back to lamboot which collects them.  In the third step, lamboot gives  each  machine  the
       list  of  machines/ports  in order to form a fully connected topology.  If any machine was
       not able to start, or if a timeout period expires before the first step completes, lamboot
       invokes wipe(1) to terminate LAM and reports the error.

       The  <bhost>  file  is  a  LAM boot schema written in the host file syntax.  See bhost(5).
       Instead of the command line, a boot schema can be specified in  the  LAMBHOST  environment
       variable.   Otherwise  a default file, bhost.def, is used.  LAM searches for <bhost> first
       in the local directory and then in the installation directory under etc/.

       In addition, lamboot uses a process schema for the individual LAM nodes.  A process schema
       (see conf(5)) is a description of the processes which constitute the operating system on a
       node.  In general, the system administrator maintains this file -- LAM/MPI users will gen-
       erally  not  need  to change this file.	It is also possible for the user to customize the
       LAM software with a private process schema.

   Remote shell invocation
       The remote shell program that is used to invoke commands on remote hosts is set	when  LAM
       is  configured.	 It  is typically rsh, but can be set to any value by the person who set-
       up/compiled LAM.  This program can be overridden at lamboot invocation time by setting the
       LAMRSH environment variable to a suitable remote shell program.	For example:

	      setenv LAMRSH "ssh -x"

       This will force LAM to use the "ssh" client to invoke programs on remote nodes, and ensure
       that "ssh" uses the -x command line flag (to suppress the ssh 1.x client  series  standard
       information  banner  that is normally output to the standard error, which would cause lam-
       boot to fail).

       Normally, lamboot uses two remote shell invocations to each node.  The first remote  shell
       invocation  is  used  to determine the user's shell on the remote node.	The second remote
       shell invocation is used to launch the desired LAM binary on the remote node.  If  the  -b
       switch  is used, lamboot will assume that the user's shell on all remote nodes is the same
       as it is on the local node, and therefore only one remote shell invocation is used,  which
       is noticably faster.

       In  either  case, on remote nodes, if the user's shell is not csh, tcsh, or bash, .profile
       is invoked by LAM before invoking any LAM binary.  This allows the user to setup paths and
       any necessary environment before LAM binaries are invoked (csh and tcsh users can put such
       setup in their $HOME/.cshrc or $HOME/.tcshrc files; bash users can put this setup in their
       $HOME/.bashrc file).

   Closing stdio
       The  stdio  of  each  LAM daemon on a remote host that is launched by lamboot is closed by
       default.  Normally, the stdio of the LAM daemon launched on the local host is left open so
       that  the  internal LAM tstdio(3) package works properly.  However, it is sometimes desir-
       able to close the stdio of the local LAM daemon as well.  For example:

	  rsh somenode lamboot -s hostfile

       This is because rsh waits for two conditions before exiting: lamboot to exit, and stdout /
       stderr  to be closed.  Without -s, stdout / stderr would not be closed, and rsh would hang
       even though lamboot had completed.  -s causes the stdout / stderr of the local LAM  daemon
       to  be closed upon invocation, which will allow rsh to complete.  Using -s will not affect
       lamboot in any other way, but it will prevent the tstdio(3) package from working properly.

   Fault Tolerance
       If the -x option is given, LAM runs in fault tolerant mode.  In this mode, nodes  exchange
       ``heart beat'' messages periodically to make sure all nodes are running and the links con-
       necting them are operational.  When a node's heart beats stop, it is declared ``dead'' and
       all  LAM  nodes	(and  processes) are notified.	This allows users to write fault tolerant
       applications that can degrade gracefully, or fully recover by replacing the  defunct  node
       with  another  (see  lamgrow(1)).  Since this mode introduces a performance penalty, it is
       not activated by default.

       lamboot -v
	   Start LAM on the machines described in the default boot schema.  Report  about  impor-
	   tant steps as they are done.

       lamboot mynodes
	   Start LAM on the machines described in the boot schema mynodes.  Operate silently.

       $LAMHOME/etc/lam-bhost.def default boot schema file

       $LAMHOME/etc/lam-conf.lam default process schema file for LAM nodes

       recon(1), wipe(1), hboot(1), tstdio(3), bhost(5), conf(5), lam-helpfile(5)

LAM 6.5.8				  November, 2002			       LAMBOOT(1)
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