fuel-dev team mailing list archive

[Andrew Woodward <xarses@xxxxxxxxx>]

>
> Firstly, 3.10-lt kernel is an LTS kernel supported by Linux Foundation

For example Cisco UCS is not validated on CentOS using 3.10. Cisco won't
provide support because they didn't validate it. Another example is if a
vendor provides kernel drives they may be bound to 2.6 and not provide
packages that cant be bound to 3.10 again because they dont test it. We
will have issues with this until RHEL is on 3.10 and vendors start to test
and validate against it.


> We've already experienced issues with hardware unsupported by 2.6.32 kernel

This is the first that I've heard of hardware problems other than OVS and
just plain missing drivers that the newer kernels have embeded (Which is
our bad). Please provide examples.

If you want to upgrade CentOS 6.x to 3.10 and make it default, you can't
this is Red Hat's job. This is a limitation that is known to the people who
select CentOS. If they dont like it, then they can use the fedora-lt kernel
at their own volition, wait for CentOS 7, or use Ubuntu. Taking away the
default kernel from CentOS 6.x violates a core assumption users are going
to make if they select to install it and makes it NOT CentOS.

Yes I object to using the 3.10 kernel any were for CentOS by default.
Again, its no longer CentOS and no longer something that we can test
effectively. We are going down the slope of needing to validate a kernel
against a myriad of hardware platforms. This is something that we
absolutely should not be attempting to do. Hardware vendors and Distos do
this for us with their default kernel for distributions they support.

again this goes back to what problem are we trying to solve by moving the
bootstrap kernel to 3.10? I'm still guessing here so you really need to
come up with a story here so that we can actually solve the problem.

It sounds like you are looking to improve UX when installing, great!.
However this is the wrong way. We can either continue to have this A/B
split between the kernel that is used by Ubuntu and the kernel we are using
for CentOS (no moving to 3.10 in CentOS does not resolve this issue) or we
can fix this by improving the approach.

1) I think that if we just want to improve the bootstrap kernel, then we
should switch bootstrap to Ubuntu, it gets a 3.8 kernel
2) If we want to solve this A/B issue then we need to prepare both CentOS
and Ubuntu bootstrap images and allow the user to switch. It's the only
complete solution and I'd guess that most of the time they will only use
one, or the other. (Unless they test one and then switch to the other).



On Fri, Mar 28, 2014 at 2:17 PM, Vladimir Kuklin <vkuklin@xxxxxxxxxxxx>wrote:

> Andrew, Dmitry N,
>
> Firstly, 3.10-lt kernel is an LTS kernel supported by Linux Foundation,
> this is not a piece of some short-term supported code. Moreover, this
> kernel has a support of much more hardware as it is not so ancient as
> 2.6.32 kernel is. We've already experienced issues with hardware
> unsupported by 2.6.32 kernel. This makes our users pretty unhappy, that
> they cannot use their newer hardware, even though it is supported by 3.10
> and Ubuntu 3.x kernels. Thus, changing bootstrap kernel allows users to use
> their newer hardware without breaking things as user is still able to
> choose the kernel for main OS installation. Thus we faced the fact that we
> need either to provide bootstrap with the newest LTS kernel or create
> several bootstrap images, which looks much more complicated. We chose the
> compromise. This is obviously a mistake, that we did not dicsuss this in
> this ML. So, if you have any objections and you think that we should revert
> this change, please, provide you arguments. In my opinion, changing only
> the bootstrap image kernel is not a big deal.
>
>
>
>
> On Fri, Mar 28, 2014 at 10:31 PM, Dmitriy Novakovskiy <
> dnovakovskiy@xxxxxxxxxxxx> wrote:
>
>> +1 to Andrew's points. I've also been dealing with a bulk of vendors'
>> pain - plugins (Cinder, Neutron) not working properly due to our CentOS
>> being not actually CentOS (kernel+qemu versions).
>>
>> ---
>> Regards,
>> Dmitriy
>>
>>
>> On Fri, Mar 28, 2014 at 11:22 AM, Andrew Woodward <xarses@xxxxxxxxx>wrote:
>>
>>> Right now master node has 2.6 kernel, bootstrap has 3.10 and target node
>>>> has an option in settings with 2.6 kernel as default.
>>>
>>>
>>> WHAT? Why is the bootstrap 3.10 already? I already spoke to the issues
>>> that some users have had about this. This should have been discussed on the
>>> ML before making a change like this.
>>>
>>> First off, I'm sorry but making the 3.10 the default kernel for our
>>> "CentOS 6.x" installs inherently makes it NOT CentOS, it becomes Fedora 18.
>>> If we are going to do this, then we might as well switch from CentOS base
>>> to a proper Fedora base. At the same time, making 3.10 the default kernel
>>> impacts vendor support. Vendors that might have supported CentOS 6.x now
>>> wont. I've already been in on a conversation with with a user, and
>>> separately two vendors that are having a hard time using our "CentOS"
>>> because we don't have a stock kernel. This removes support-ability from the
>>> list of reasons to use CentOS, which is one of the core reasons I've seen
>>> organizations select it.
>>>
>>> Second, what is the goal here?
>>>
>>> * if we are trying reduce issues from master -> bootstrap -> target
>>> node? switching kernel around? If this is the case then we really should
>>> just change master and bootstrap to Ubuntu (which I've been considering
>>> raising anyways).
>>>
>>> * If we are trying to reduce the OVS issues (or other old kernel
>>> issues), then the current workup is correct, the user should have to
>>> explicitly choose a kernel that wasn't part of the base distribution, this
>>> is important as is must be their choice and not default to enter into a
>>> mode that reduces their support.
>>>
>>> * If we are trying to get CentOS to a more modern kernel, then we really
>>> just have to wait for CentOS 7 otherwise we are really better off tracking
>>> Fedora instead of CentOS
>>>
>>> Third, this is changing our user story of "No vendor lock-in" to "You're
>>> stuck with Mirantis". We really need to take a step back an evaluate where
>>> we are going. If we want to maintain our on proprietary distro then we need
>>> to stop beating around and do it, and do it well. If we are going to fight
>>> vendor lock-in, then we need to be more cautions about what distro packages
>>> we are modifying and why. We also need to not replace distro packages but
>>> instead maintain a clean distro repos and a MOS repo, this will grant us a
>>> clear line of what we are doing and better allow others to participate
>>> (like bringing in other distros, vendor compatibility, and others)
>>>
>>>
>>> On Fri, Mar 28, 2014 at 5:08 AM, Matthew Mosesohn <
>>> mmosesohn@xxxxxxxxxxxx> wrote:
>>>
>>>> I propose that since we do kernel-lt 3.10.30 as a default for installs
>>>> and bootstrap, we should default to it for Fuel master node as well.
>>>> I believe we should keep the 2.6.32 kernel around just in case there
>>>> is a regression in using the newer kernel, but maybe we can drop it
>>>> after a release cycle or two if there are no major issues.
>>>>
>>>> The build tiem option I mentioned to you would be to optionally
>>>> generate a bootstrap image with the 2.6.32 kernel during ISO build. It
>>>> isn't likely we will need to build it, but it should be easy to swap
>>>> back if the need arises.
>>>>
>>>> On Fri, Mar 28, 2014 at 4:03 PM, Dmitry Pyzhov <dpyzhov@xxxxxxxxxxxx>
>>>> wrote:
>>>> > Guys,
>>>> >
>>>> > we have two kernels: default 2.6.32 and kernel-lt 3.10.30. And we
>>>> have three
>>>> > types of CentOS nodes: master node, bootstrap, target node.
>>>> >
>>>> > Right now master node has 2.6 kernel, bootstrap has 3.10 and target
>>>> node has
>>>> > an option in settings with 2.6 kernel as default.
>>>> >
>>>> > There is a suggestion from our team members to use 3.10 kernel
>>>> everywhere
>>>> > and add build-time option for 2.6.
>>>> >
>>>> > Any concerns?
>>>> >
>>>> > --
>>>> > Mailing list: https://launchpad.net/~fuel-dev
>>>> > Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
>>>> > Unsubscribe : https://launchpad.net/~fuel-dev
>>>> > More help   : https://help.launchpad.net/ListHelp
>>>> >
>>>>
>>>> --
>>>> Mailing list: https://launchpad.net/~fuel-dev
>>>> Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
>>>> Unsubscribe : https://launchpad.net/~fuel-dev
>>>> More help   : https://help.launchpad.net/ListHelp
>>>>
>>>
>>>
>>>
>>> --
>>> Andrew
>>> Mirantis
>>> Ceph community
>>>
>>> --
>>> Mailing list: https://launchpad.net/~fuel-dev
>>> Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
>>> Unsubscribe : https://launchpad.net/~fuel-dev
>>> More help   : https://help.launchpad.net/ListHelp
>>>
>>>
>>
>> --
>> Mailing list: https://launchpad.net/~fuel-dev
>> Post to     : fuel-dev@xxxxxxxxxxxxxxxxxxx
>> Unsubscribe : https://launchpad.net/~fuel-dev
>> More help   : https://help.launchpad.net/ListHelp
>>
>>
>
>
> --
> Yours Faithfully,
> Vladimir Kuklin,
> Fuel Library Tech Lead,
> Mirantis, Inc.
> +7 (495) 640-49-04
> +7 (926) 702-39-68
> Skype kuklinvv
> 45bk3, Vorontsovskaya Str.
> Moscow, Russia,
> www.mirantis.com <http://www.mirantis.ru/>
> www.mirantis.ru
> vkuklin@xxxxxxxxxxxx
>



-- 
Andrew
Mirantis
Ceph community