MAAS GRUB chainloads the distro to save time that otherwise the system
would spend trying to netboot with all capable NICs.
Investigating LP:2022084, we discovered that with this chain, RHEL GRUB2
tries to validate the kernel using MAAS shim, causing the secure boot
process to fail. Given the nature of shim and secure boot process in
general, there's not much we can do on MAAS side to fix this behaviour.
As a hotfix, we temporarily drop the chainloading for other distros so
that they could boot securely (even though with some extra wait time).
Ubuntu will still be chainloaded because the MAAS shim trusts the certs
our kernels/bootloaders are signed with. I also don't think Windows
boot loader can be affected by any shims whatsoever, so MAAS will still
try to chainload it.
(cherry picked from commit f3b643e5f40f171326df134a0827a93fdc0137e4)
MAAS currently creates a DNS record for each interface in a host
by simply using its interface name. Whenever an interface has the
'_' character, the code uses it anyway, which is currently breaking
bind as this character is not allowed on domain names.
This patch fixes that by verifying it and replacing the incorrect
character.
5b79ab7e5 - bump piston dependency, drop now useless monkeypatch
4117bcf3b - drop monkeypatch for piston emitter, since it's been fixed in piston itself