Managing AIX with SMIT

David Carver

AIX administrators have a variety of tools available to help with systems administration, including:

• Web-based System Manager, an object-oriented GUI that provides assistance for less experienced administrators and remote administration of one or more machines from any client platform.
• The System Management Interface Tool, or SMIT, a task-oriented, menu-based interface that supports all common administration tasks. There are two versions of SMIT: an X Window version that provides GUI features such as point-and-click operations, and an ASCII text version that can be run on any character-mode terminal.
• AIX command strings, which can be invoked directly by the user from the command line or through scripts. Both Web-based System Manager and SMIT execute these same commands from within their interfaces.

SMIT Overview

SMIT is a unique and powerful tool for systems administration. It offers the following features:

• Two modes of operation (ASCII and X Window)
• An interactive, menu-driven, comprehensive user interface
• User assistance (helps) and prompting
• System management activity logging
• Fast paths to common system management tasks
• Command preview
• User-added SMIT screens

The initial SMIT menu (Figure 1) organizes systems management tasks into high-level categories, such as Software Installation and Maintenance, Devices, and Users. Lower level menu, selector, and dialog screens guide the user to choose tasks and enter the information required to complete them.

SMIT's task-oriented structure allows even novice administrators can perform routine system administration tasks without having to learn exact command spellings, syntax, and option values. Standard function keys are used to invoke common functions such as requesting help, canceling a screen and returning to a previous screen, entering a command-line shell, or exiting from SMIT.

SMIT screens reflect the actual configuration of the managed system. The contents of the menus and other screens depend on what hardware and software is actually installed and on whether any user-written SMIT screens have been added. SMIT covers most common systems administration and configuration tasks.

User Assistance and Prompting

User assistance is available for menus, menu choices, and input and output fields. In ASCII SMIT, pressing the F1 (Help) key displays context-sensitive help for the current menu or for the selected item in a dialog screen. For many selection fields, input prompting is also provided. For example, the screen for adding a physical disk to a volume group displays a list of all available disks when you press the F4 key, so there is no need to recall and enter any additional commands to find out what disks are available. For Yes and No and multiple-choice response fields, pressing the Tab key cycles through the valid responses. You can also select Using SMIT (information only) from the main SMIT menu for global help on using SMIT.

System Management Activity Logging

SMIT logs all system management activity in two files that usually reside in the user's home directory. The smit.log file records all SMIT actions, including the name of SMIT screens that were displayed, the command string run by SMIT, output from the command, and any error output. Additionally, pressing the F8 key during a SMIT session causes the current screen image to be written to the smit.log file. The smit.script file records all high-level command strings and scripts that the system executes.

These log files are useful not only as a record of changes to the system configuration made via SMIT, but also because lines from the logs can be copied and pasted into a script when an operation needs to be repeated many times. SMIT creates the initial valid command string, which helps ensure that the script will work properly the first time. See "Using SMIT to Simplify System Administration" below for an example of how to use SMIT output in a script.

Fast Paths

One common complaint about menu-driven tools is that traversing the menu hierarchy slows down experienced users. SMIT, however, has a complete set of fast paths to speed up interaction for power users. Fast paths are command strings that bypass menu and choice screens and go directly to an application menu or even to the final dialog screen for performing the desired task. For example, the smitty install fast path command displays the Software Installation and Maintenance menu, while the smitty update_all command displays the dialog for updating all installed software to the latest level. Fast paths are available for most of the system management tasks in SMIT and can be added for user-created screens. Press the F8 key on a SMIT screen to see the fast path name for that screen.

The following table shows the fast path commands for the menu choices on the initial SMIT menu. Appendix C in the "How to Use SMIT" whitepaper, referenced at the end of this article, provides a complete list of fast paths.

Application                                                  Fast Path
Software Installation and Maintenance                        install
Software License Management                                  licenses
Devices                                                      dev
System Storage Management (Physical & Logical Storage)       storage
Security and Users                                           security
Communications Applications and Services                     commo
Print Spooling                                               spooler
Problem Determination                                        problem
Performance and Resource Scheduling                          performance
System Environments                                          system
Processes and Subsystems                                     src

Pressing the F6 (Command) key on a dialog after completing all input fields displays the command string that is executed when the Enter key is pressed. For administrators who want to know exactly what the tool is doing, this feature is extremely useful for verifying the command to be executed. It is also a good way to learn command syntax for future use outside of SMIT. I find that the first time I perform a task, SMIT is the easiest way to do it. But, command line is often quicker if the commands are short. Finally, you can copy the text from the command preview window and paste it into a script that you're editing, as shown in the example in a later section.

User-Added SMIT Screens

SMIT also offers the capability of adding your own menus and dialogs to support other administration tools that you use in your environment. The AIX General Programming Concepts: Writing and Debugging Programs manual and the whitepaper referenced below contain instructions for creating your own menu, selector, and dialog screens, and adding them to the SMIT database. I have not made much use of this capability yet, but have found the process of adding customized SMIT screens seems to be straightforward.

Using SMIT to Simplify Systems Administration

Here are some examples of SMIT's usefulness. I have already mentioned that SMITTY works on both graphical and non-graphical terminals. It can also be used over very slow dial-up networks, through network firewalls that block the X protocol, and from systems that do not have an X server installed. I have successfully used SMITTY to reconfigure a system from halfway around the world using a pay phone and a laptop computer running telnet.

Another example shows how SMIT can make it easier to execute commands that have a lot of weird parameters. Figure 2 shows the command preview window that was displayed when I was defining a network interface for TCP/IP. The mktcpip command in this case used seven parameters.

A third example illustrates the results of copying SMIT output into user-written scripts for performing essentially the same task multiple times. We have two IBM SP2 systems, which have a total of 99 nodes. Each node has its own CPU, disk, memory, and operating system, much like a company with 99 RS/6000 workstations running AIX. If I need to define a remote printer on all of the nodes (see Figure 3), I can use the Command Preview function to generate a command string, then cut and paste it to a file called /tmp/mycommand.

The /tmp/mycommand file is called from another script file called node_command_driver that reads from a list of node hostnames and copies the /tmp/mycommand file to the remote node, executes the file on the remote node, and cleans up after itself.

$ cat  node_command_driver  

#!/bin/sh
for  node in 'cat list_of_nodes'
do
echo $node
rcp /tmp/mycommand $node:/tmp/mycommand
remsh $node sh /tmp/mycommand
remsh $node rm  /tmp/mycommand
done

$cat list_of_nodes

azure01
azure03
azure05
...
azure80

$ cat /tmp/mycommand

/usr/lib/lpd/pio/etc/piomisc_ext mkpq_remote_ext  -q 'lp' -h
'paperboy'  -r 'raw' -t 'aix' -C 'FALSE'  

Additional Information

For more information on using SMIT, you can start SMIT and select "Using SMIT" (information only) from the main SMIT menu. Also see the chapter on SMIT in the AIX manual, General Programming Concepts: Writing and Debugging Programs in the AIX Documentation Library Service. You can find the library service online at:

http://www.ibm.com/servers/aix/library

An IBM whitepaper on "How to Use SMIT" is also available at:

http://www.rs6000.ibm.com/sysv/articles/smit.htm

The Advanced Computing Center for Engineering & Science (ACCES) provides advanced scientific and technical computing services to faculty, staff, and students at The University of Texas at Austin. To promote the advance of computational science, ACCES makes supercomputing resources available to the nation's academic research community in the form of vector parallel supercomputers, scalable parallel multicomputers, scientific visualization systems, data-caching fileservers, and data archival fileservers as a member of the National Partnership for Advanced Computational Infrastructure, sponsored by the Advanced Computational Infrastructure and Research division of the National Science Foundation. ACCES is a member of the Coalition of Academic Supercomputing Centers (CASC).