[PATCH] add capability to install grub2 but not update the MBR

Gene Czarcinski gczarcinski at ec.rr.com
Tue Sep 16 10:45:50 UTC 2014


On 09/16/2014 02:49 AM, Vratislav Podzimek wrote:
> On Mon, 2014-09-15 at 09:26 -0400, Gene Czarcinski wrote:
>> On 09/15/2014 08:59 AM, Vratislav Podzimek wrote:
>>> On Mon, 2014-09-15 at 08:54 -0400, Gene Czarcinski wrote:
>>>>> On 09/15/2014 02:30 AM, Vratislav Podzimek wrote:
>>>>>>> Where is the kickstart support? Or do you by "Kickstart install" mean
>>>>>>> installation where both 'ks=...' and 'inst.nombr' are provided as boot
>>>>>>> options? I think we still need something like 'bootloader --nombr' if
>>>>>>> this is the right way to go to fix that bug.
>>>>>>>
>>>>>>>
>>>>> I decided to keep things as simple as possible and just have to boot
>>>>> parameter "nombr" which will apply to any install including kickstart.
>>>>> I did consider adding code so that like --extlinux, you could specify
>>>>> --nombr on kickstart's bootloader command.  But, more code is a chance
>>>>> for additional errors.
>>>>>
>>>>> But, if there is a strong desire to have --nombr as another option on
>>>>> kickstart's bootloader command, I can add it.
>>> A general policy in the Anaconda installer is that every feature should
>>> be implemented in kickstart first. That's the most comprehensive and
>>> feature-complete "installation mode". So please add that code as well.
>> v1.1 coming "real soon now"
>>
>> Since you brought up the fact that it is Anaconda Installer policy that
>> every feature be implemented in kickstart first, how about my kickstart
>> "--reclaim" option for kickstart's btrfs command.
>>
>> The problem:  When I manually configure the storage layouts on a regular
>> gui or live install, one of the things I can do is to delete an existing
>> subvolume so that the space and the subvolume's name can be reused.  In
>> kickstart, currently I can one create new subvolumes or re-use an
>> existing subvolume.  There is also the requirement that the the rootfs
>> ("/") subvolume always be freshly "formatted".
>>
>> So, to provide the same capability to kickstart that is available in a
>> regular install, I create a "reclaim" patch.  With the patch applied,
>> you can specify something like:
>>            btrfs  /           --subvol  --name=root1  btrfs_vol --reclaim
>>            btrfs  /home  --subvol  --name=home  btrfs_vol  --noformat
>>
>> which will result in two subvolume.  The home subvolume is reused
>> whereas if the root1 subvolume already exists, it will be deleted and
>> then reallocated.
>>
>> Comments??
> I'm not a BTRFS expert, but as far as I understand the issue and use
> case, that looks good to me except that I don't understand why you need
> the --reclaim option at all. I think that if --noformat is omitted the
> subvolume should be "formatted"/reused.
>
As currently implemented in anaconda for btrfs, --noformat and 
--useexisting do the same thing and simply reuse an existing subvolume.  
If neither is specified, the anaconda attempt to allocate a new 
subvolume which fails because the name already exists.  You could 
specify a new name which did not already exist but that leaves the space 
unavailable.  You could also boot into rescue mode and delete the 
unwanted subvolume.  Anaconda requires that rootfs ("/") and /boot be 
freshly formatted.

This is different that the meanings of --noformat and --useexisting on 
the logvol command where --useexisting means to reuse and format it (in 
btrfs the equivalent of reformat is to delete the subvol and then 
reallocate it).

When I originally suggested this functionality, I suggested that 
--useexisting be the option but I was shot down because that would be a 
significant change in how things worked and could break some existing 
kickstart configuration files.  Thus, --reclaim

Gene


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