Using and Administering

ll_start_host Subroutine

Purpose

This subroutine starts a task on a selected machine.

Library

LoadLeveler API library libllapi.a

Syntax

  int ll_start_host(char *host, char *start_cmd);

Parameters

host

Is the name of the node on which you want to start the task.

start_cmd

Is the actual command to execute on the node, including flags and arguments.

Description

This function must be invoked for all the machines returned from the ll_get_hostlist subroutine once and only once by the Parallel Master. Acquiring the start_cmd is the responsibility of the Parallel Master. The user may pass this information through the arguments or environment keywords in the job command file.

The Parallel Master must:

• Issue error messages as appropriate.
• Exit when ll_start_host returns a negative value. The Parallel Master exit status is included in the job mail returned to the user.

Return Values

This subroutine returns an integer greater than one to indicate the socket connected to the Parallel Slave's standard I/O (stdio).

Error Values

-2

Cannot get LoadLeveler step ID from environment

-4

Nameserver cannot resolve host

-6

Cannot connect to host

-7

Cannot send PASS_OPEN_SOCKET command to remote startd

-9

The command you specified failed.