[svlug] Booting to different kernel?

Scott DuBois linux at roguehorse.com
Mon Jun 9 08:59:34 PDT 2014

On 06/09/2014 07:09 AM, Karen Shaeffer wrote:
> On Sun, Jun 08, 2014 at 10:27:57PM -0700, Scott DuBois wrote:
>> On 06/08/2014 08:13 PM, Karen Shaeffer wrote:
>>> On Sun, Jun 08, 2014 at 07:25:30PM -0700, Scott DuBois wrote:
>>>> On 06/07/2014 01:09 PM, Karen Shaeffer wrote:
>>>>> On Sat, Jun 07, 2014 at 12:00:07AM -0700, crquan wrote:
>>>>>> Yes, you may look /boot/grub/menu.lst and better to change in
>>>>>> /etc/default/grub (For Ubuntu),
>>>>>> there you may just change one line GRUB_DEFAULT=... and run
>>>>>> update-grub to update
>>>>>> /boot/grub/menu.lst; if you manually change /boot/grub/menu.lst,
>>>>>> that's not recommended,
>>>>>> because in future if you update ubuntu, get another kernel will
>>>>>> overwrite /boot/grub/menu.lst,
>>>>>> so you'd better to change /etc/default/grub, future kernel upgrades
>>>>>> would take care of that,
>>>>> --- end quoted text ---
>>>>> Hi,
>>>>> Yes, but that's the difference between someone who is an expert in linux
>>>>> systems and a casual user. I would definitely prefer to manage my config
>>>>> files myself. I've been doing that since 1997 and learn far more when some
>>>>> script messes it up. On the other hand, my point of view isn't applicable
>>>>> to most users and certainly wasn't best advice to John. In retrospect, I
>>>>> should have just ignored the call for help and minded my own business.
>>>>> enjoy,
>>>>> Karen
>>>> Hmmm, don't know if this would be considered any kind of expert issue
>>>> unless expert is anyone doing things beyond point-and-click users but,
>>>> here are a couple of links that reference the material previously mentioned.
>>> Hi Scott,
>>> I don't think grub requires too much expertise. It is very simplistic for
>>> basic booting. You can get quite expert with network booting using pxe,
>>> for example. I once helped Penguin Computing port Scyld clusterware from
>>> RHEL4 to RHEL5, where I ported the compute nodes. And their use of pxe
>>> was quite fun and interesting. The compute nodes were diskless. To run a
>>> job, you needed to specify what software and resources were needed. And then
>>> the nodes were booted using a double kernel process, and all the software
>>> required to run the application was pulled in over the LAN as part of the
>>> boot process. Using pxe in this environment, booting maybe hundreds or even
>>> thousands of compute nodes required some expertise.
>>> I manage my grub config files, because I have been known to run my own custom
>>> kernels with custom commandline options configured in the grub config files, so
>>> grub can pass them into the kernel at boot time. Running a stock Ubuntu or RedHat
>>> kernel has its drawbacks, if you care about optimizing your operating system.
>>> If you know what you are doing, managing your own grub config files doesn't
>>> require much more effort than managing the grub user interface scripts, in
>>> my opinion.
>>> enjoy,
>>> Karen
>> Hi Karen,
>> Interesting note, thanks for sharing that info.
>> As each system is different in the performance and use for any given
>> application, it would make sense that custom tuning one's kernel would
>> be beneficial until such time a new kernel is released and one would
>> want to take advantage of the improvements made in the recent release.
>> Then the management repeats itself to strip the new additions from the
>> current release and write them into the custom deployment.
> Hi Scott,
> Yes, but in custom appliances or application stacks, you often don't use the
> kernel version of the base distribution. Additionally, you often do serious
> customization of the distribution as well. So, you typically wouldn't be
> directly tracking update releases of the base distribution. Yes that is
> a lot of extra work, but appliance teams often do it that way. I have even
> worked on appliances where they didn't use a base distribution at all, using
> a full custom, minimized system software layer with a heavily patched kernel.

Yes, my phone, TV, router and I think even my blu-ray are all running on
some custom version of the kernel. My desktop, standard Ubuntu LTS.

> Of course, none of this is applicable to most users of linux. And, so, I'll
> try and just mind my own business in the future. My point of view is not
> really relevant to most users. But the links you have posted are relevant
> to the typical user.

Oh I don't know if I'd go that far : )

You brought up some fun and interesting points that many don't think
about day to day. Linux is really all around us but most people usually
only focus on the interface they are looking at when they turn on their
computer or from where they bought it. Odds are good their smart fridge
or TV are running some custom Linux build but they don't care as long as
they can nav the controls and watch their shows.

Unfortunately (or fortunately depending on one's stance) the larger
portion of users really just need their OS to work on a daily basis so
they can move on with their regular tasks. They choose Linux based
systems for their own personal reasons and at times something goes wrong
to which there are a fair amount of people to turn to if one knows where
to look. But of those people, only a few are willing to be forthcoming
in considerate and thoughtful support. Enter people like yourself who
have a plethora of experience and knowledge then go out of your way to
pass that knowledge over to others who can benefit from it to make their
lives a little smoother and easier.

> On the other hand, there may be some young folks who are interested in becoming
> linux system software experts. Such folks might find my point of view worthy
> of their consideration. YMMV.

Everyone's opinion is worthy and it's what makes discussion forums fun,
interesting and educational as well as a more "personal" touch to
getting help with issues we encounter.

In the world of Linux adopters, it's the "rare few" who take the time
from their personal lives and endeavours to help someone else in a
thoughtful and compassionate way, without agenda, to insure the choice
of being a part of the Linux community is one of personal growth,
enlightenment and liberation. It's a noteworthy cause to be a
participant when that participation is provided in a way that is
beneficial to all and for the improvement of the society.

Scott DuBois
President EBLUG
BSIT Software Engineering
Freenode: Roguehorse

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