Why does kickstart installation of LVM on Software RAID fail with error message on Red Hat Enterprise Linux 7?

Issue

• Using the following partitioning information for installation, but the installer fails while checking storage.

bootloader --location=mbr --driveorder=sda,sdb --append="crashkernel=auto rhgb quiet"
clearpart --drives=sda,sdb --all --initlabel
part raid.01 --size 500 --asprimary --ondrive=sda
part raid.04 --size 500 --asprimary --ondrive=sdb
part raid.02 --size 17600 --asprimary --ondrive=sda
part raid.05 --size 17600  --asprimary --ondrive=sdb
part swap --size=1992 --ondisk=sda
part swap --size=1992 --ondisk=sdb
part raid.03 --size 8000 --grow --ondrive=sda
part raid.06 --size 8000 --grow --ondrive=sdb
raid /boot --fstype ext4 --device md0 --level=RAID1 raid.01 raid.04
raid /home2 --fstype ext4 --device md1 --level=RAID1 raid.02 raid.05
raid pv.01 --fstype ext4 --device md2 --level=RAID1 raid.03 raid.06
volgroup sysvg pv.01
logvol / --vgname=sysvg --size=6000 --name=root

• The problem seems to be with Storage

18:59:44,807 DEBUG anaconda: new disk order: ['sda', 'sdb']
18:59:45,055 DEBUG anaconda: new disk order: ['sda', 'sdb']
18:59:45,083 DEBUG anaconda: stage1 device cannot be of type mdarray
18:59:45,083 DEBUG anaconda: stage1 device cannot be of type mdarray
18:59:45,083 DEBUG anaconda: stage1 device cannot be of type mdarray
18:59:45,083 DEBUG anaconda: stage1 device cannot be of type disk
[................]
18:59:45,084 WARN anaconda: sda1 not bootable    <================== error that sda1 is not bootable
18:59:45,084 DEBUG anaconda: _is_valid_format(sda1) returning False
18:59:45,084 DEBUG anaconda: is_valid_stage1_device(sda1) returning False
18:59:45,084 DEBUG anaconda: _is_valid_disklabel(sda2) returning True
18:59:45,084 DEBUG anaconda: _is_valid_size(sda2) returning True
18:59:45,084 DEBUG anaconda: _is_valid_location(sda2) returning True
18:59:45,084 WARN anaconda: sda2 not bootable    <================== error that sda2 is not bootable
18:59:45,084 DEBUG anaconda: _is_valid_format(sda2) returning False
18:59:45,084 DEBUG anaconda: is_valid_stage1_device(sda2) returning False
18:59:45,084 DEBUG anaconda: _is_valid_disklabel(sda3) returning True
18:59:45,085 DEBUG anaconda: _is_valid_size(sda3) returning True
18:59:45,085 DEBUG anaconda: _is_valid_location(sda3) returning True
18:59:45,085 WARN anaconda: sda3 not bootable    <================== error that sda3 is not bootable
18:59:45,085 DEBUG anaconda: _is_valid_format(sda3) returning False
18:59:45,085 DEBUG anaconda: is_valid_stage1_device(sda3) returning False
18:59:45,085 DEBUG anaconda: _is_valid_disklabel(sda4) returning True
18:59:45,085 DEBUG anaconda: _is_valid_size(sda4) returning True
18:59:45,085 DEBUG anaconda: _is_valid_location(sda4) returning True
18:59:45,085 WARN anaconda: sda4 not bootable    <================== error that sda4 is not bootable
18:59:45,085 DEBUG anaconda: _is_valid_format(sda4) returning False
18:59:45,085 DEBUG anaconda: is_valid_stage1_device(sda4) returning False
18:59:45,086 DEBUG anaconda: stage1 device cannot be of type lvmvg
18:59:45,086 DEBUG anaconda: stage1 device cannot be of type lvmlv
18:59:45,086 ERR anaconda: BootLoader setup failed: failed to find a suitable stage1 device <================== Bootloader failed.

• Why does this fail?