I'm trying to use the CentOS-8-x86_64-1905-dvd1.iso as the http source for my PXE/kickstart install.
I'm struggling to understand why the installer is looking of squashfs.img and a directory named LiveOS, neither of which exist in the above iso image.
Should I be using the CentOS-8-x86_64-1905-boot.iso instead? I followed https://docs.centos.org/en-US/8-docs/advanced-install/assembly_preparing-for-a-network-install but there was no mention made of which iso to use.
If you've gotten that message, then you are probably attempting to install CentOS 8 with a CentOS 7 initrd.img and vmlinuz. You have to change the initrd.img and vmlinuz that you point to in your APPEND and KERNEL line in your tftpboot file. Here's an example of a working file.
This page will tell you where to find those files in your CentOS 8 iso:
https://docs.centos.org/en-US/8-docs/advanced-install/assembly_preparing-for-a-network-install/
The CentOS document https://docs.centos.org/en-US/8-docs/advanced-install/assembly_creating-installation-sources-for-kickstart-installations/ is wrong. You are better off using rsync to copy the ISO's contents. See my comment above for details.