#GPLv3

Copy content of usr/lib/dracut/modules.d to /usr/lib/dracut/modules.d/

1) CEPH

Install ceph-common
In /etc/dracut.conf add:

filesystems+="ceph"

Regenerate initramfs

Append to PXE:

root=ceph://name:secret@10.11.23.1:6789,10.11.23.2:6789,10.11.23.3:6789:/centos7/root

2) RBD

In /etc/dracut.conf add:

add_drivers+="rbd"
filesystems+="ext4 xfs"

Regenerate initramfs

Append to PXE:

root=rbd://name:secret@10.11.23.1:6789,10.11.23.2:6789,10.11.23.3:6789:/POOL/rbd_image

3) HTTP

In initramfs you should have: curl,pigz,tar
In /etc/dracut.conf add:

add_dracutmodules+="http"

Regenerate initramfs

Append to PXE:

root=http://10.20.0.2/root/root.tar.gz

root.tar.gz might be created with tar --exclude='./tmp/' --exclude='./var/log/' --exclude='./dev/' --exclude='./sys/' --exclude='./proc/*' -czf /httproot/root.tar.gz --one-file-system -C /noderoot/ ./