CentOS - Jul 2014 - Installing CentOS7 boot loader into the /boot partition

I did not see any way, during the CentOS7 install, to install the 
CentOS7 boot loader into the /boot partition rather than to the MBR of a 
drive. How does one do this in the installation of CentOS7 ?

On 07/16/2014 12:22 AM, Edward Diener wrote:
> I did not see any way, during the CentOS7 install, to install the
> CentOS7 boot loader into the /boot partition rather than to the MBR of a
> drive. How does one do this in the installation of CentOS7 ?
>
>
See: 
https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/7/html/Installation_Guide/sect-disk-partitioning-setup-x86.html
and the section about selecting which disk on which to install the 
bootloader.  Specifically, there's a 'button' (looks more like a
link in
the screenshot) called "Full disk summary and bootloader" on the 
"Installation Destination"**screen, at the bottom.  I haven't
tried this
yet (but I will soon), but it would seem that by telling it the device 
on which /boot resides the bootloader will be installed there.

On 07/17/2014 06:37 AM, Edward Diener wrote:
> Not choosing a bootloader did not work. Without the ability to tell 
> the CedntOS7 installation to install its bootloader in my /boot 
> partition, I cannot use CentOS7. For me the CentOS7 developers have 
> really messed up.
File a bug with Red Hat's bugzilla; CentOS just rebuilds that source, 
and bugs like this must be fixed upstream.

There is other discussion around the web on this issue for GRUB2 (which 
is where the issue lies).  The core is that GRUB2 is quite a bit larger 
than GRUB 1, and thus it may or may not be safe to install to a 
partition.  However, you can force it; one such post about doing this is at:
https://ask.fedoraproject.org/en/question/10666/install-grub2-to-a-partition/

I'm going to be doing this myself at some point in the near future; I'll
try to remember to fully document what I need to do to make it work.

On 07/17/2014 09:33 AM, Edward Diener wrote:
> ...
> The grub2 boot loader is installed in a /boot partition in my Fedora 20
> installation and works properly. ...
Fedora is not CentOS; upstream's take would likely be, 'while it may be 
good enough for Fedora, this is an Enterprise Linux, not Fedora, and 
thus we're not going to support anything this sketchy.'  There are 
numerous posts on the Ubuntu forums about it; it's not isolated to CentOS.
> How hard would it really be for grub2 to check to make sure it has
> enough space to install itself into a /boot partition ?
It does do this, and there is an alternate, but not recommended, option 
(which is what the --force does).  The actual error from grub-setup:
grub-setup: warn: Attempting to install GRUB to a partition instead of 
the MBR. This is a BAD idea.
grub-setup: warn: Embedding is not possible. GRUB can only be installed 
in this setup by using blocklists. However, blocklists are UNRELIABLE 
and its use is discouraged.
>
> I finally saw some posts about how to install grub2 for CentOS7 into a
> /boot partition manually and I will do that. But the Anaconda installer
> should never have created this headache to begin with no matter what
> they say.
Anaconda didn't create the headache; the developers of GRUB2 did by not 
properly supporting installation to a partition without saying that it 
is a BAD idea.
> All other Linux distros I have used, such as Suse, Mint,
> Ubuntu, Mageia etc., give the ability of installing the bootloader into
> a /boot partition even when defaulting to grub2. There is no excuse for
> this Anaconda nonsense from Fedora other than programmer egotism.
>
It's a GRUB2 problem, not an anaconda one, and GRUB2 is a GNU project, 
not a Fedora one.

If I were in release engineering for upstream, I wouldn't allow anaconda 
to do something that the GRUB2 authors say is a BAD idea; there will be 
at least one person who will lose data or have an unbootable system by 
using the feature (the GNU GRUB programmers put the warning message in; 
talk to them about why they did that and what the GNU GRUB2 project 
plans to do about properly supporting installation in an 
enterprise-worthy fashion to a partition and not to the MBR).

And I want to be able to do the bootloader install to a partition 
myself, but I do understand why it would be supported for the 
non-Enterprise Fedora but not for the Enterprise version.

On 07/17/2014 02:41 PM, Edward Diener wrote:
> Programming is about calculations as well as logic. It cannot be 
> impossible to calculate how big core.img is, how much space is in the 
> partition in which grub2 is installed and either tell the end-user it 
> can or cannot be done. Things like "it's bad to install grub2 into
a
> partition" mean nothing in the computer programming world. The first 
> rule of programming: the bit is on or it is off. 
What the error message is saying is that 'we know the bootloader is too 
big to fit in the partition's boot sector, so we hide it with 
blocklists, but they're unreliable (filesystem utilities could 
potentially overwrite them), and so that makes it a bad idea.' The 
--force parameter is the user telling grub-setup 'I know you know it's 
too big and will use blocklists and they're unreliable but I don't care:
use them anyway!' The bootloader has a significant amount of code that 
is not inside the filesystem and either must 'hide' in the
partition's
boot sector or be hidden by 'lying' about the sectors that the 
bootloader is using (the blocklist method).

The programmers at the GNU GRUB project have determined that it is not 
reliably supportable to put GRUB2 on a partition, rather than putting it 
in the MBR (a whole different ball of wax is EFI boot support.....).  
Correcting this is something that the GRUB project people will have to 
properly fix (and it's probably not easy to do, or they would have 
already done it).  The Fedora project supports it, at least as far as 
Fedora *supports* anything (that is, if it breaks, you keep the pieces) 
whereas an Enterprise distribution with paying customers can't 
reasonably do that, since if it breaks they have to support fixing it.  
That's what the service contract buys, after all.

The CentOS project rebuilds that Enterprise linux distribution verbatim, 
as so won't support it either, until the upstream supports it.

But if you want to do it manually, you can.  And I will be trying this, 
but on a bit of an oddball system, not your run-of-the-mill 
BIOS-boot-to-MBR systems.

On 07/17/2014 02:41 PM, Edward Diener wrote:
> Programming is about calculations as well as logic. It cannot be 
> impossible to calculate how big core.img is, how much space is in the 
> partition in which grub2 is installed and either tell the end-user it 
> can or cannot be done. 
For more on this from the GNU GRUB developers, please see 
https://www.gnu.org/software/grub/manual/grub.html#BIOS-installation