The immediate issue is with Fedora/ppc64 and /ppc64le which currently
use extended partitions, breaking the virt-builder ‘--size’ parameter,
eg:
$ virt-builder --arch ppc64le fedora-26 --size 20G
...
[ 21.6] Resizing (using virt-resize) to expand the disk to 20.0G
virt-resize: error: /dev/sda5: partition not found in the source disk image
(this error came from '--expand' option on the command line). Try running
this command: virt-filesystems --partitions --long -a /var/tmp/vbf67b8c.img
However more generally MBR is broken and should die. GPT is supported
by all modern virtual bootloaders, so just default to it.
Notes:
* This is different from mandating a UEFI bootloader.
* I am not planning to rebuild any existing images except the
F26 ppc64 & ppc64le ones.
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