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.
nim -Fo check -a debug=yes SPOTNamewhere SPOTName is the name of your SPOT.
From Web-based System Manager
Alternatively, you can use the following command to get the address:
lsnim -a enter_dbg SPOTNamewhere 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 .
st Enter_dbg_Value 2where 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.
nim - Fo check SPOTNamewhere 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.
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.
A minimum bosinst.data file for debugging purposes would contain the following lines:
control_flow: BOSINST_DEBUG = yes