the system and trying again - this works and install goes through. Any
suggestions on how to debug this further - and what are the possible
points to check
This makes me think that there is no issues with your kickstart file, there can be a problem for first instance disk detection and wipeout of RAID signatures which doesn't let you
deploy first time. In such situations, it's always great to capture anaconda logs which you can get in /tmp of tty2 else, you can append the anaconda boot parameters as follows
linux inst.ks=<your kickstart file path> inst.sshd=1 sshpw=testpassword ip=192.168.0.100 netmask=255.255.255.0 gateway=192.168.0.1 nameserver=192.168.0.1
This enables your system's sshd during installation and when you get any problem, just ssh to this system using Windows Putty or from other Linux system with root and password as "testpassword" without quotes, you will get anaconda shell. On this shell, you can go to /tmp and here are our logs. These logs can be read, program.log will show you which command was executed last and what's it's return value.
The disk names can be found in /proc/partitions or using parted command. So you can troubleshoot from here.
Back to the problem, anaconda might not be able to wipeout the preinstalled raid signatures from your disks, so you might want to force clean it by adding a %pre script as follows.
wipefs -a -f /dev/sda
wipefs -a -f /dev/sdb
Considering your disks names are /dev/sda and /dev/sdb. Please note that above two commands in %pre section will fully wipe out your filesystems on /dev/sda and /dev/sdb, if you are not sure about the disk naming which can get changed across reboots, you can consider replacing those names with /dev/disk/by-id values too, which will hard-code the kickstart, to make it dynamic, you will need to inject little scripting into it.
Additionally, how does your kickstart partitioning stanza looks like? Does the clearpart statement have --all --drive=sda,sdb with it?