---
name: "hboot"
section: "1"
platform: "linux"
package: "lam-runtime"
version: "7.1.4-7.2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/hboot"
---

# hboot(1)

Start LAM on the local node.

## NAME

hboot - Start LAM on the local node.

## SYNOPSIS

hboot \[-dhstvNV\] \[-c conf\] \[-I inet\_topo\] \[-R rtr\_topo\]

## OPTIONS

- **-d**

  Turn on debugging.  This implies -v.

- **-h**

  Print the command help menu.

- **-s**

  Close stdio of child processes.

- **-t**

  Terminate ([tkill(1)](/tkill/1.md)) any previous LAM session before starting.

- **-v**

  Be verbose.

- **-N**

  Go through the motions but do not actually take any action.

- **-V**

  Format and print the process schema.

- **-c conf**

  Use conf as the process schema.

- **-I inet\_topo**

  Set the $inet\_topo variable in the process schema.

- **-R rtr\_topo**

  Set the $rtr\_topo variable in the process schema.

## DESCRIPTION

Most MPI users will probably not need to use the *hboot* command; see [lamboot(1)](/lamboot/1.md).

The *hboot* tool can be understood as a generic utility that starts multiple processes on the local node, based on information in a process schema. It is not restricted to starting LAM. It is part of the startup sequence preformed by [lamboot(1)](/lamboot/1.md).

A process schema is a description of the processes which constitute the operating system on a given node. Naturally, the process schema used by *hboot* should be the one that describes LAM on a node. The grammar of the process schema is described in [conf(5)](/conf/5.md).

When starting LAM on a remote machine using [rsh(1)](/rsh/1.md), the open file descriptors of the processes started by *hboot* must be closed in order for [rsh(1)](/rsh/1.md) to exit. This is done by using the *-s* option. The *-t* option can be used to force a [tkill(1)](/tkill/1.md) on the machine before attempting to start LAM.  This feature is used by [lamboot(1)](/lamboot/1.md) to handle the case where a user might start a machine a second time without using [lamwipe(1)](/lamwipe/1.md) to terminate the previous LAM session.

The *-I* and *-R* options set their respective variables to the given values. The $inet\_topo variable is typically used by the LAM Internet datalinks that communicate with other nodes. The $rtr\_topo variable is passed to the LAM router that handles network and topology information. The variables can also be set in the process schema file (see [conf(5)](/conf/5.md)) but their values are overridden by the command line options.

When LAM is started, the kernel records all processes that attach to it, including all the processes in the process schema. It is the job of [tkill(1)](/tkill/1.md) to use this information to remove these processes from the node.

## EXAMPLES

- hboot -v

  Start LAM on the local node with the default process schema. Report about every step as it is done.

- hboot -c myconfig

  Boot the local node with the custom process schema, *myconfig*.

## FILES

- laminstalldir/etc/lam-conf.lamd

  default node process schema, where "laminstalldir" is the directory where LAM/MPI was installed

- laminstalldir/etc/lam7.1.4helpfile

  Default location for help file for diagnostic messages that  *hboot* may generate.

- /tmp/lam-$USER@hostname

  kill file for the LAM session on machine hostname, where $USER is the userid.

## DIAGNOSTICS

Using [ps(1)](/ps/1.md) after *hboot* will display, among others, the LAM processes that have been started. They may be killed one by one with [kill(1)](/kill/1.md), or all at once by killing the LAM kernel process with a HUP signal. The preferred method is to use the LAM tool [tkill(1)](/tkill/1.md) which should kill them all at once, and also remove the kill file. New users should make liberal use of [ps(1)](/ps/1.md) to gain confidence that the system is working properly. In a disaster, [ps(1)](/ps/1.md) and [kill(1)](/kill/1.md) are your only hope of recovery.

## SEE ALSO

[lamboot(1)](/lamboot/1.md), [tkill(1)](/tkill/1.md), [conf(5)](/conf/5.md), [lam-helpfile(5)](/lam-helpfile/5.md)