Producing Debug Output for NIM BOS Installations

AIX Version 4.3 Network Installation Management Guide and Reference

Producing Debug Output for NIM BOS Installations

Due to problems in the network or in the NIM configuration, clients may fail to boot properly and/or install. When this happens, it may be necessary to produce debug information in order to determine the cause of the problem. If a client machine fails to configure properly from the network boot image, debug output from the boot image can be obtained by building the debug-enabled image and attaching a tty to the client system. This will display the commands and output that are run as the client is configured before further processing is done by AIX.

If the system has been booted from the network boot image, but failures are still occurring during a BOS installation, it may be necessary to collect debug information from the BOS install program. The commands and output from the BOS install program will automatically be displayed on the tty if the boot image was built debug-enabled. If the boot image was not built for debugging, output can be obtained by either setting a value in a bosinst.data file or by entering special codes at the installation menus.

When problems arise during a NIM BOS installation, you will most likely see system "hangs." Viewing the debug output can be extremely useful, because you will be able to see the commands that failed. The problem may be a misconfiguration of the network adapter or an inability to perform an operation from the client to the server. By examining the debug output, you can see what failed and make corrections to avoid the error in the future.

You will see the showled command running in the debug output. This command displays status values on the LEDs on the front of the machine. Frequently, known problems and solutions are referenced by the LED value that is displayed when a problem occurs. Some machines do not have LEDs for displaying such information. Therefore, when debugging problems on such machines, special attention should be given to observing the values that the showled commands are displaying.

Obtaining debug information from a network installation can save you time in determining the root cause of a problem. Usually, the problem will be an incorrect definition in the NIM environment that can be found without the debug information. However, with the debug information, you can significantly reduce the scope of the investigation.

Producing Debug Output from a Network Boot Image

Create debug versions of the network boot images using the check operation from the Web-based System Manager or SMIT interfaces or by using the following command:
```
nim -Fo check -a debug=yes SPOTName
```
where SPOTName is the name of your SPOT.
Get the address for entering the debugger:
From Web-based System Manager
1. From the NIM Resources container, double-click the SPOT resource to open the properties notebook.
2. Click the Boot Image Information tab in the properties notebook to obtain the address.
Alternatively, you can use the following command to get the address:
```
lsnim -a enter_dbg SPOTName
```
where SPOTName is the name of your SPOT. The displayed output will be similar to the following:
```
spot1:
   enter_dbg = "chrp.mp 0x001840d4"
   enter_dbg = "chrp.up 0x00160b7c"
   enter_dbg = "rs6k.mp 0x001840d4"
   enter_dbg = "rs6k.up 0x00160b7c"
   enter_dbg = "rspc.mp 0x001840d4"
   enter_dbg = "rspc.up 0x00160b7c"
```
Write down the enter_dbg address for the client you are going to boot. For example, if your client is an rs6k-uniprocessor machine, you would write down the address 160b7c .
Attach a tty device to your client system (port 1).
Set up and perform the NIM operation that will require the client to boot over the network. Boot the client over the network.
After the client gets the boot image from the SPOT server, the debug screen will appear on the tty. At the > prompt, enter:
```
st Enter_dbg_Value 2
```
where Enter_dbg_Value is the number you wrote down in step 2 as your machine type's enter_dbg value. Specifying a 2 at the address of the enter_dbg value prints the output to your tty.
Type g for go and press Enter to start the boot process.
Use Ctrl-s to temporarily stop the process as you watch the output on the tty. Use Ctrl-q to resume the process.
To rebuild your boot images in non-debug mode, use the following command:
```
nim - Fo check SPOTName
```
where SPOTName is the name of your SPOT.
If the boot image is left in debug mode, every time a client is booted from these boot images, the machine will stop and wait for a command at the debugger ">" prompt. If you attempt to use these debug-enabled boot images and there is not a tty attached to the client, the machine will appear to be hanging for no reason.

Producing Debug Output from the BOS Install Program

There are two ways to obtain debug output from the BOS install program. Method A involves entering a special value at one of the installation menus. Method B uses a bosinst_data resource to tell the installation program to display debug output.

Method A: To Produce Debug Output When Not Using a bosinst_data Resource

To enable debugging for the BOS install program, start by performing all the processing you would normally do to install a client.
Since you are not using a bosinst_data resource, you will be prompted to supply information about the installation to the BOS install program.
Select your console.
Select your language.
The Welcome to Base Operating System Installation and Maintenance menu is displayed. Instead of selecting one of the options, enter 911 at the prompt and press Enter.
Continue the normal procedure for selecting options and specifying data until the installation begins. Debug output will be sent to the client's display as the installation proceeds.

Method B: To Produce Debug Output When Using a bosinst_data Resource

To enable debugging for the BOS install program, set the value BOSINST_DEBUG = yes in the control_flow stanza of the bosinst.data file that you are using for your bosinst_data resource.
A minimum bosinst.data file for debugging purposes would contain the following lines:
```
control_flow:
     BOSINST_DEBUG = yes
```
In addition to the processing you would normally do to install a client, include the modified bosinst_data resource as a resource for the operation. After the client boots over the network, it will use the bosinst_data resource to obtain settings for the installation. If the only data specified in your bosinst.data file is BOSINST_DEBUG = yes , you will be prompted for the remaining required information before the installation will continue. Debug output will be sent to the client's display as the installation continues.