Once you have PXE you can do all the things -- NFS boot, HTTP boot, iSCSI boot, and so on. There are several open source projects that support this. I think the most recent iteration is iPXE.
That's true, though I always have felt that if I needed PXE+TFTP to boot the bootloader I might as well just load a kernel+initrd from the same place and be done with it; I couldn't remove the TFTP requirement so anything else would just be extra things to configure. If UEFI can really do pure HTTP (as discussed upthread) then I may need to reevaluate. (Well, for Raspberry Pis I'll have to keep TFTP, but maybe in other contexts I can drop it)
> While standard PXE clients use only TFTP to load parameters and programs from the server, iPXE client software can use additional protocols, including HTTP, iSCSI, ATA over Ethernet (AoE), and Fibre Channel over Ethernet (FCoE). Also, on certain hardware, iPXE client software can use a Wi-Fi link, as opposed to the wired connection required by the PXE standard.
Does iPXE have a ca-certificates bundle built-in, is there PKI with which to validate kernels and initrds retrieved over the network at boot time, how does SecureBoot work with iPXE?
