Philip, after installation, MAAS configures nodes to PXE-boot, but the GRUB delivered chainloads a locally-installed GRUB on the hard disk. The PXE-boot part is a requirement of the MAAS environment. (If systems booted straight from the hard disk, the MAAS server could not re-deploy them.) Re-thinking the design so that only one GRUB is loaded (via PXE) might help with this problem, but would render the design fragile to the case when the MAAS server becomes unavailable.
Philip, after installation, MAAS configures nodes to PXE-boot, but the GRUB delivered chainloads a locally-installed GRUB on the hard disk. The PXE-boot part is a requirement of the MAAS environment. (If systems booted straight from the hard disk, the MAAS server could not re-deploy them.) Re-thinking the design so that only one GRUB is loaded (via PXE) might help with this problem, but would render the design fragile to the case when the MAAS server becomes unavailable.