Creating Diagnostic Test Images#

In uncommon situations you may want to execute a self-contained diagnostic program as a compute node image. In this case, "self-contained" means the diagnostic program itself functions as a kernel and does not need an initrd.

An example self-contained diagnostic program is the memtest86+ memory diagnostic, which can be downloaded from www.memtest.org.

To check the memtest and create a boot configuration that works for both EFI and legacy booting using the ISO file:

Download the latest compressed Linux 64-bit ISO from www.memtest.org. For example, mt86plus_8.00_x86_64.iso.zip.
Uncompress the downloaded file to expose the ISO:
```
unzip mt86plus_8.00_x86_64.iso.zip
```

Mount the ISO:

mkdir memtest
sudo mount memtest.iso memtest

Create a new boot configuration that includes the EFI binary:

cw-bootctl create name=Memtest kernel=@memtest/EFI/BOOT/bootx64.efi

Configure the desired node to execute the new boot configuration:
```
cw-nodectl -in10 set _boot_config=Memtest
```
Ensure that you have a method to view serial output from that node. For example, if serial output uses ttyS1:
```
cw-bootctl -i Memtest update cmdline="console=ttyS1,115200"
```
Reboot the node:
```
cw-nodectl -in10 reboot
```

Alternatively, you can use the binary files from www.memtest.org and combine some of the commands:

Download the latest binary file from www.memtest.org. For example, mt86plus_8.00.binaries.zip.

Uncompress the downloaded file:

[admin@head1]$ unzip mt86plus_8.00.binaries.zip
Archive:  mt86plus_8.00.binaries.zip
  inflating: mt86p_800_i586
  inflating: mt86p_800_la64
  inflating: mt86p_800_x86_64

Create a new boot configuration that includes the memtest kernel:

[admin@head1]$ cw-bootctl create name=mt86p_800_x86_64 kernel=@mt86p_800_x86_64
Uploading mt86p_800_x86_64 to 7f2b0f5bbd9b40fa862a60dc8dcfd6b9 as kernel:
   100.0% complete, elapsed: 0:00:00.3

   done.
Created Boot Configuration
  mt86p_800_x86_64

Configure the desired node to execute the new boot configuration and reboot the node:

[admin@head1]$ cw-nodectl -in0 set _boot_config=mt86p_800_x86_64 then reboot
Results
  n0
    success: True
Nodes
  n0: reboot succeeded