How to install several kernels on Debian

[Yedidyah Bar David]

On Tue, Dec 15, 2015 at 2:03 PM, Oleg Goldshmidt <pub at goldshmidt.org> wrote:
> Yedidyah Bar David <linux-il at didi.bardavid.org> writes:
>
>> On Sun, Dec 13, 2015 at 3:06 PM, Oleg Goldshmidt <pub at goldshmidt.org> wrote:
>>>
>>> this is something that Red Hat do without being asked
>>> (they keep several versions, usually 3), so it is something that seems
>>> natural to me.
>>
>> Generally, should work similarly in Debian.
>
> So what's the apt-get equivalent of yum install (as apt-get install is
> similar to yum update)?

In a sense, you are right, but not in the way you intended: yum
install will also
update an installed package if an update is available.

>
>> This break due a specific different issue, not because Debian does not
>> support this in general.
>
> I think that the root cause is that "apt-get install" updates rather
> than installing together.
>
>> No idea about your specific issue. Did you try to also upgrade udev and
>> initramfs-tools?
>
> Will my 3.2 keep working? I have no confidence in that. Again, I do not
> want to "upgrade" anything - I want to switch between several kernels at
> will. I also do not want to compile - I want stock Debian kernels.

AFAICS wheezy had 3.2, jessie has 3.16.

My laptop was upgraded from wheezy to jessie and has both kernels installed.
IIRC I successfully booted the 3.2 one after the upgrade, didn't try
that recently,
as I have no need for that.

Didn't check about udev and initramfs-tools.

The kernel packages normally arrive with a kernel image, plus many modules.
initramfs-tools is used to build an initrd image, which mainly includes the
relevant modules.

In principle, building such an initrd of the 3.2 kernel with
jessie-updated tools
is indeed risky.

I am pretty certain that the above is almost identical in rhel/centos/fedora,
except that upgrading there between releases is significantly different.
-- 
Didi