F16 Alpha GRUB install failure

[Adam Williamson]

On Mon, 2012-02-13 at 19:25 -0700, Chris Murphy wrote:
> 
> On Feb 13, 2012, at 7:10 PM, Adam Williamson wrote:
> 
> > On Mon, 2012-02-13 at 14:25 -0700, Chris Murphy wrote:
> >> 
> >> I think the problem is GRUB2's own install script/app, doesn't do a great job of accounting for disks partitioned where the 1st partition comes less than 35KB after the MBR, and as the core.img is too large it fails to install between the MBR and partition 1.
> >> 
> >> Strangely though, anaconda manages to get it to install without a complaint.
> > 
> > No, that's clearly not the problem here, because this thread is about
> > installing grub to the front of a partition - *not* to the MBR.
> 
> The GRUB2 manually doesn't outright say "unsupported" or "not
> recommended" but it does say insertion prior to the 1st partition is
> what's recommended. I've had zero problems with GRUB legacy installing
> into specific partitions, but worse than 50% failure with GRUB2 so
> I've given up on stuffing it into specific partitions.
> 
> 
> > anaconda only calls grub2-install, with appropriate parameters, to
> > install grub. It doesn't do anything particularly special or clever.
> 
> Well I've got a number of cases on F16 where anaconda's call to
> grub2-install produces a smaller core.img than calling grub2-install
> directly. I don't have an explanation for this, but it's just enough
> of a difference in size that it causes problems with older
> partitioning schemes that start partition 1 at sector 63.
> 
> Is anaconda passing --force by default?

When installing to a partition not to the MBR, yeah, it does.

It's easy enough to look at anaconda's actual code for all this. It's in
pyanaconda/bootloader.py . Here it is in all its glory:

    def install(self):
        # XXX will installing to multiple drives work as expected with GRUBv2?
        for (stage1dev, stage2dev) in self.install_targets:
            args = ["--no-floppy", self.grub_device_name(stage1dev)]
            if stage1dev == stage2dev:
                # This is hopefully a temporary hack. GRUB2 currently refuses
                # to install to a partition's boot block without --force.
                args.insert(0, '--force')

            rc = iutil.execWithRedirect("grub2-install", args,
                                        stdout="/dev/tty5", stderr="/dev/tty5",
                                        root=ROOT_PATH)
            if rc:
                raise BootLoaderError("bootloader install failed")

I suppose the --no-floppy may make it a tad bit smaller. You could try
that on your manual invocations.
-- 
Adam Williamson
Fedora QA Community Monkey
IRC: adamw | Twitter: AdamW_Fedora | identi.ca: adamwfedora
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