QA

#33223 showed us how to setup a SCSI-drive to kickstart a SLES installation from the initramfs by using kexec to chain-load several "bootloader" steps.
This knowledge now needs to be preserved for future in form of documentation. This includes ( ACs ):

• How to setup the "magic" bootstrap SCSI-disk
  • Partitioning
  • zipl installation
• How to use qnipl (partly done in https://github.com/nicksinger/dracut-qnipl/blob/master/README.md)
• Limitations/Pitfalls/Improvements
• Reproduce the setup

Notes:

• https://progress.opensuse.org/projects/openqav3/wiki#s390x-Test-Organisation would be maybe a good place to put all the info
• Move dracut-qnipl into a non-private repo (maybe openQA org?)
• bootstrap SCSI-disk is a shared medium between several LPARs and Infra/gschlotter is needed to link LPAR <-> SCSI-bootstrap-disk
• Example cmd to start an LPAR remote (e.g. from a x86_64 host): snipl -f ./snipl.conf -s P0069A27-LP3 -A fa00 --wwpn_scsiload 500507630713d3b3 --lun_scsiload 4001401100000000 --ossparms_scsiload "install=http://openqa.suse.de/assets/repo/SLE-15-Installer-DVD-s390x-Build533.2-Media1 hostip=10.161.159.3/20 gateway=10.161.159.254 Nameserver=10.160.0.1 Domain=suse.de ssh=1 regurl=http://all-533.2.proxy.scc.suse.de"

Notes about the "magic" bootstrap disk:

linux-kboz:~ # lsblk
NAME                                        MAJ:MIN RM  SIZE RO TYPE  MOUNTPOINT
sda                                           8:0    0   10G  0 disk  
  sda1                                        8:1    0   10G  0 part  
  36005076307ffd3b30000000000000111         254:0    0   10G  0 mpath 
    36005076307ffd3b30000000000000111-part1 254:1    0   10G  0 part  
sdb                                           8:16   0   10G  0 disk  
  sdb1                                        8:17   0   10G  0 part  
  36005076307ffd3b30000000000000111         254:0    0   10G  0 mpath 
    36005076307ffd3b30000000000000111-part1 254:1    0   10G  0 part

linux-kboz:/boot/zipl # sfdisk -d /dev/sda 
label: dos
label-id: 0x1323e80f
device: /dev/sda
unit: sectors

/dev/sda1 : start=        2048, size=    20969472, type=83

linux-kboz:/tmp/test # mount /dev/mapper/36005076307ffd3b30000000000000111-part1 /tmp/test
linux-kboz:/tmp/test # find .
.
./zipl
./zipl/bootmap
./image_installer
./lost+found
./initrd_installer
./zipl.conf
./initrd_zipl
./image_4.12.14-16.2
./image_zipl
./custom_initramfs
./image_4.12.14-11.2

linux-kboz:/tmp/test # find .
.
./zipl
./zipl/bootmap
./image_installer
./lost+found
./initrd_installer
./zipl.conf
./initrd_zipl
./image_4.12.14-16.2
./image_zipl
./custom_initramfs
./image_4.12.14-11.2
linux-kboz:/tmp/test # file *
custom_initramfs:   XZ compressed data    <- generated by dracut with qnipl-module enabled
image_4.12.14-11.2: Linux S390
image_4.12.14-16.2: Linux S390
image_installer:    Linux S390
image_zipl:         Linux S390
initrd_installer:   XZ compressed data
initrd_zipl:        XZ compressed data
lost+found:         directory
zipl:               directory
zipl.conf:          ASCII text             <- IIRC needed for `zipl` to generate/write the z-bootloader

linux-kboz:/tmp/test # cat zipl.conf 
## This file was written by 'grub2-install/grub2-zipl-setup'
## filling '/etc/default/zipl2grub.conf.in' as template
## with values from '/etc/default/grub'.
## In-place modifications will eventually go missing!

[defaultboot]
defaultmenu = menu

[custom]
    target = /mnt/network_boot/zipl
    ramdisk = /mnt/network_boot/custom_initramfs
    image = /mnt/network_boot/image_4.12.14-16.2
    parameters = "rd.break=initqueue TERM=dumb plymouth.enable=0 "

:menu
    target = /mnt/network_boot/zipl
    timeout = 0
    default = 1
    prompt = 1
    1 = custom