I figured out a huge portion of what I was doing wrong.
Here is a snippit from syslinux config
label kickstart1 menu label ^1 Minimal Kickstart kernel vmlinuz append initrd=initrd.img inst.repo=hd:LABEL=CENTOS7:/ inst.stage2=hd:LABEL=CENTOS7:/ inst.ks=hd:LABEL=BOOT:/ks/minimal.cfg
I prefer grub and it translates to grub.
I am not sure if this works with UEFI systems though
Note that there is a CENTOS7 label and a BOOT label.
That is because there is a FAT32 /dev/sdb1 labeled BOOT and an ext3 /dev/sdb2 labeled CENTOS7.
I did this because you can simply copy the ISO to /dev/sdb2. But I think this will work all on 1 partition with FAT32 and if you copy the “contents” of the iso file to the partition. That is due to the file size limitation of FAT32, basically it will not accomidate the large DVD iso that is the CentOS 7 install.
But a new issue came up, kickstart is not sure which is the boot disk. In my tests on a live system, /dev/sdb was the boot disk and /dev/sda was the flash.
Just another thing to figure out.