Re: change default os

[Jordan Uggla]

On Thu, Mar 14, 2013 at 5:06 AM, Simon Hobson <address@hidden> wrote:
> It would help if the stock file had a comment to that effect.

Indeed, it would. Because of the way that Debian handles updates to
configuration files adding such a comment might have the unfortunate
consequence of requiring user input about the change during upgrades,
but it can't hurt to recommend to Debian in a bug report/feature
request that such a comment be added.

>
> Your comments may be technically correct, but making statements like :
>> Please don't try anything that Simon has recommended in the above
>> email, everything he has said has been overly complicated and has had
>> issues with breaking in various ways on upgrades.
>
> Is far from helpful. It makes the list seem hostile, where only certain elite 
> people are allowed to post. Contrast two approaches :
> 1) Ignore everything A said, they're stupid things to do ...
> 2) While what A says will work, a better way is ... because ...
> Which is more helpful ? Which makes the list seem a more open place to ask 
> for help ? Especially when statement A is factually incorrect.

One problem that I see often is that once people get and answer that
"works" they leave the discussion, even if that answer has issues in
the longer term (like issues with upgrades) and they never see the
response from others about better methods. I agree that my response
was far more hostile than it should have been though, and I apologize.

>
>>> An alternative way is to re-order the components in /etc/grub. On my Debian 
>>> system, Windows (and others) are detected by30_os-prober - if you change 
>>> the numbering so this comes before nn_linux, then the Windows OS will come 
>>> before Linux in the list, meaning Windows will boot by default. You'll need 
>>> to take care to deal with this change any time Grub gets updated and the 
>>> installer wants to put new config files in.
>>
>>Hence it's hardly worth mentioning. I highly recommend against doing
>>this. My general feeling is that you should never make any changes in
>>/etc/grub.d/ at all (only modifying /etc/default/grub is enough for
>>95% of people, and for 4 of the next 5% adding custom entries via
>>/boot/grub/custom.cfg is enough). If you're in the 1% that can't get
>>what you need/want from grub-mkconfig without modifying /etc/grub.d/
>>then I would recommend writing your grub.cfg completely manually.
>
> I strongly disagree with that stance. Again, I don't know if it's a Debian or 
> stock GRUB issue, but for Xen hosts it makes sense to re-order the components 
> - assuming you want to retain the default "boot latest version" operation. 
> The other techniques you mention all (AFAIK) require manual intervention any 
> time you upgrade either Xen or the Kernel.

It's true that with grub 1.99 and older this was the case, and though
I cringed a little whenever people did this for Xen, it made sense.
With grub 2.00 and submenus you can either set the default to the
latest Xen kernel (the main menu entry), or to a specific Xen kernel
version (inside the "Advanced options" submenu). Xen was the one
corner case I can think of for modifying /etc/grub.d/ pre grub 2.00,
and I can't think of any that apply with grub 2.00.

Sorry again for the unneeded hostility.

-- 
Jordan Uggla (Jordan_U on irc.freenode.net)