Open Stack

Hello all, I’m an Operator that has worked with DIB here for the last few months to get some working images for our Private Cloud.  The only major issue I could come up with at the summit was the way grub 0.97 is treated in the bootloader element.  For Centos 6, I had to find an element that could actually install grub 0.97 since when yum goes to update the kernel, it tries to update the grub config but not the extlinux config and in our cloud we need the VMs to stay updated.  I’m sure the elements I have locally could be useful but the current thinking in my organization is to deprecate our Centos 6 use as quickly as possible.

I’ve also run into an issue reported here [0] that makes installing a bootloader in Centos 6 a pain in either extlinux or grub 0.97.  That’s really a quirk of the OS packages I’m using to build the image but still an odd situation.  I’ve updated my VMs that build images to the Mitaka RDO release and with that release came the qemu-kvm-ev packages so I’m hopeful that these new packages might fix this bug.  If not I’ll have to keep using Ubuntu to build my Centos 6 images.

Security is a concern for sure but in my environment I have Jenkins spawn a VM in the cloud to build these images and I give these VMs enough ram to build the image in memory instead of copying the image to disk.

I also have a requirement to standardize our images to using XFS for the root partition due to our flavors including a large amount of root disk.  The reasoning here is that XFS resizes faster than ext4 so I would have a concern if libguestfs could not do this.  It seems like I could just use DIB to fix any images that were created from your libguestfs scripts though so it might not be that much of a concern.

[0]: https://bugs.launchpad.net/diskimage-builder/+bug/1477179

Peter Nordquist

From: Mariam John [mailto:mariamj at us.ibm.com]
Sent: Thursday, May 05, 2016 07:43
To: OpenStack Development Mailing List (not for usage questions) <openstack-dev at lists.openstack.org>
Subject: Re: [openstack-dev] [trove][sahara][infra][Octavia][manila] discussion of image building in Trove


[Inactive hide details for Victoria Martínez de la Cruz ---05/05/2016 08:12:33 AM---Hi all, A few things:]Victoria Martínez de la Cruz ---05/05/2016 08:12:33 AM---Hi all, A few things:

From: Victoria Martínez de la Cruz <victoria at vmartinezdelacruz.com<mailto:victoria at vmartinezdelacruz.com>>
To: "OpenStack Development Mailing List (not for usage questions)" <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>
Date: 05/05/2016 08:12 AM
Subject: Re: [openstack-dev] [trove][sahara][infra][Octavia][manila] discussion of image building in Trove

________________________________



Hi all,

A few things:

- I agree that moving from DIB to libguestfs is a bold move and that we should try to avoid changing tools unless highly necessary. The downsides we found for DIB are detailed in this spec [0] and Ethan (in this same thread) also added valid points on the Sahara case. My concern here is, should we stick with DIB just because is the standard for image creation? Shouldn't we take in consideration that some projects, like Sahara, are moving away from?

I think it would be worth trying to see if DIB can address the concerns raised by the different projects around image building and improve upon that. By improving DIB, I think all these projects and OpenStack in general can benefit from it.

- In the long term it would be ideal that we reach to a common solution for image creation for all the projects that need tailored images: Trove, Sahara, Octavia, Manila, and IIRC, Kolla and Cue.
- In the short term, I'm on board or working on having tools based on DIB for image creation in Trove.
- Amrith, Pete is working on the image creation process for Trove. The spec is up there [0]. I think is his work to kick-off that repository.

Best,

Victoria

[0] https://review.openstack.org/#/c/295274/

2016-05-04 23:20 GMT-03:00 Amrith Kumar <amrith at tesora.com<mailto:amrith at tesora.com>>:
As we discussed at summit, (and consistent with all of the comments) we should move ahead with the project to advance the image builder for Trove and make it easier to build guest images for Trove by leveraging the DIB elements that we have in trove-integration.



To that end, the infra [1] and governance [2] changes have been submitted for review. The Launchpad tracker [3] has been registered.



I am working on taking the existing DIB elements in trove-integration and putting them in the new repository (openstack/trove-image-builder). I am also going to continue to watch this conversation and record any shortcomings with the existing DIB elements in Launchpad [3] and work on fixing those as well. Pete mentions one in his earlier email and I’ve logged that in Launchpad [4].



Thanks,



-amrith



[1] https://review.openstack.org/#/c/312805/

[2] https://review.openstack.org/#/c/312806/

[3] https://launchpad.net/trove-image-builder

[4] https://bugs.launchpad.net/trove-image-builder/+bug/1578454







From: Mariam John [mailto:mariamj at us.ibm.com<mailto:mariamj at us.ibm.com>]
Sent: Wednesday, May 04, 2016 4:19 PM
To: OpenStack Development Mailing List (not for usage questions) <openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>>

Subject: Re: [openstack-dev] [trove][sahara][infra][Octavia][manila] discussion of image building in Trove



The way I see this, these are the 2 main concerns I have been hearing regarding image building in Trove:
1) making the process simple and easy for users
2) addressing the issue of security

I dont think there is any argument regarding the benefits of moving the database elements to a seperate repository and packaging and managing them from there.

It looks like the case that we make for whether to use libguestfs or DIB for image building are in the technical details of how image building happens and their nuances - assuming that ease of use & having a simple interface to build secure images matters most, I wonder if the end-users would be concerned about these details.

By addressing some of the issues like:
- moving the Trove elements to a new repository
- adding support for new distros
- creating a wrapper script for building an image -getting the Trove guest agent code & configuration files
- managing environment variables better

I believe it will make a huge improvement in terms of simplifying and improving the ease of use for end users and hence could be the low hanging fruit that we can implement in the mean time. I agree that switching from DIB to any other tool is a big step and we need to put alot of thought into it like many others have suggested. Like Pete mentioned earlier in one of the links, there are couple of other tools available for building images. I am sure we could make the case for each of these tools and how it is easier/faster/better than the others. If we go down this route experimenting with libguestfs, is there anything stopping us couple of releases down the lane from wanting to experiment with some other tool because libguestfs doesn't perform well? The end user could use any tool they want to use to create images if they wish to do so but I agree and believe that Trove should support a standard way of building images (DIB being an OpenStack project, I would assume that would be the standard) and do it well keeping it simple and easy to use as opposed to what it is today.

I think we should split this into 2 tasks
- one for going forward with seperating image building into a seperate repository and putting all efforts into simplifying the current process, and
- second, to have a joint collaboration with the DIB/TripleO team to raise concerns regarding DIB and see if we can address them in turn OR if using a different tool like libguestfs makes sense at that point.

Thanks,
Mariam.

[Inactive hide details for Peter MacKinnon ---05/04/2016 12:39:15 PM---On 5/4/16 12:52 PM, Gregory Haynes wrote: > On Wed, May 4]Peter MacKinnon ---05/04/2016 12:39:15 PM---On 5/4/16 12:52 PM, Gregory Haynes wrote: > On Wed, May 4, 2016, at 08:55 AM, Flavio Percoco wrote:

From: Peter MacKinnon <pmackinn at redhat.com<mailto:pmackinn at redhat.com>>
To: openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.org>
Date: 05/04/2016 12:39 PM
Subject: Re: [openstack-dev] [trove][sahara][infra][Octavia][manila] discussion of image building in Trove

________________________________



On 5/4/16 12:52 PM, Gregory Haynes wrote:
> On Wed, May 4, 2016, at 08:55 AM, Flavio Percoco wrote:
>> On 04/05/16 15:05 +0000, Amrith Kumar wrote:
>>> I'm emailing the ML on the subject of a review ongoing in the Trove project regarding image building[1].
>>>
>>> TL;DR
>>>
>>> One of the most frequent questions that new users of Trove ask is how and where to get guest images with which to experiment with Trove, and how to build these images for themselves. While documentation about this exists in multiple places (including [2], [3]) this is still something that can do with some improvement.
>>>
>>> Trove currently uses diskimage-builder for building images used in testing the product and these can serve as a good basis for anyone wishing to build an image for their own use of Trove. The review [1] makes the argument for the libguestfs based approach to building images and advocates that Trove should use this instead of diskimage-builder.
>> At the summit we discussed the possibility of providing an implementation
>> that
>> would allow for both DIB and libguestfs to be used but to give priority
>> to DIB.
>> Since there's no real intention of just switching tools at this point, I
>> believe
>> it'd be good to amend the spec so that it doesn't mention libguestfs
>> should be
>> used instead of DiB.
>>
>> The goal at this stage is to provide both and help these move forward.
>>
>>> I believe that a broader discussion of this is required and I appreciate Greg Haynes' proposal at the design summit to have this discussion on the ML. I took the action item to bring this discussion to the ML.
>>>
>>> Details follow ...
>>>
>>> Before going further, I will state my views on these matters.
>>>
>>> 1. It is important for the Trove project to do things quickly to make it easier for end users who wish to use Trove and who wish to build their own images. I am not concerned what tool or tools a person will use to build these images.
> ++. One of the biggest issues I see users of DIB hit is ease of use for
> 'just make me an image, I don't care about twiddling knobs'. A wrapper
> script in trove is one way to help with this, but I am sure there are
> other solutions as well... maybe by rethinking some of our fear about
> using elements as entry points to an image build, or by simply making
> element's with better defaults.
>
>>> 2. If we provide multiple alternatives to image building as part of the Trove project, we should make sure that images built with all sets of tools are equivalent and usable interchangeably. Failing to do this will make it harder for users to use Trove because we will be providing them with a false choice (i.e. the alternatives aren't really alternatives). This is harder than it sounds given the combination of tools, operating systems, and the source(s) from which you can get database software.
>> Maintaining both in the long run will be harder especially because, as
>> you
>> mentioned, the output must be usable interchangeably. However, I think
>> we're at
>> a point, based on the comments in [1] made by Pino Toscano, Luigi Toscano
>> and
>> some other folks that it'd be beneficial for us to have this discussion
>> and to
>> also experiment/test other options.
>>
>> The Sahara team seems to be going in a direction that differs with the
>> one used
>> by the infra team and the one we're headed to (although they overlap in
>> some
>> areas).
>>
> I would highly recommend against having two sets of image building code
> for Trove - given DIB's current design there should not be any need for
> this and there's a HUGE downside to maintaining two sets of code to do
> the same thing in-tree. Ideally a single set of code would be used while
> being able to be run in different environments if there are mutually
> exclusive requirements being proposed by users.

Well, certainly one downside in the case of Trove (and probably
elsewhere) with DIB is the src tree matrix of datastore-by-distro
elements required to support various guest image combinations, leading
to a proliferation of directories and files. We feel this can be greatly
simplified using a libguestfs approach using a minimal set of bash and
directly applicable data files (e.g., systemd unit files, conf files,
etc.).

>
> What seemed very apparent to me in the summit session is that there are
> a set of issues for Trove relating to image building, mostly relating to
> reliability and ease of use. There was no one who even mentioned let
> alone strongly cared about the issues which actually differentiate the
> existing DIB build process from libguestfs (which is isolation). If that
> has changed for some reason, then my recommendation would be to use a
> tool like virt-dib which will allow for a single image building code
> base while solving all the raised issues in the spec. I suspect when
> this is tried out the downsides to booting a VM will highly outweigh the
> benefits for almost all users (especially in trove's gate),

Anecdotally, it takes the same amount of time for a CentOS7 MySQL build
(~ 7 minutes) with either toolchain.

> but if the
> libguestfs docs are to be believed this should be trivial to try out.

Not quite sure what you mean by "to be believed"?

>
>
>>> 3. Trove already has elements for all supported databases using DIB in the trove-integration project but these elements are not packaged for customer use. Making them usable by customers is a relatively small effort including providing a wrapper script (derived from redstack[4]) and providing an element to install the guest agent software from a fixed location in addition to the development and testing version that is better suited to Trove development [5] and [6].
>>>
>>> 4. My comments on various patch sets in the review[1].
>>>
>>> I agree with Monty and Greg Haynes that we should understand the deficiencies if any in DIB, and if it is in fact the case that they are "intractable/unsolvable", we should switch toolchains. This discussion should include issues faced by the Trove team as well as other teams that may have faced problems with DIB (such as the sahara team who described some of them in the past).
>> ++
>>
>> Agreed with the above. I'm think collaboration should be the preferred
>> way. I
>> don't think I've enough technical insight on this topic to provide a
>> detailed
>> list of things that are good/bad on either of these tools but I wanted to
>> mention that I believe providing support for both in the short run is
>> good for
>> us and it helps to make a better decision on what tool works best for the
>> project.
> Rewriting image building code in order to find out if we want to use a
> tool seems completely backwards. Obviously, if some external team wants
> to do this there's nothing stopping them, but what we should focus on
> are what problems actually effect out user base and what we can do to
> solve them. We should *not* be focusing on finding ways to support
> various image building frameworks without a clear benefit to doing so.

The various image building frameworks have been noted here
http://docs.openstack.org/image-guide/create-images-automatically.html
including libguestfs. So it's not like it is an unknown quantity. In the
interest of innovation I'm not sure I understand the hearty reluctance
to explore this path. We are proposing simply another Trove repo with an
alternate (and recognized) image build method. This is not displacing
any established tool for Trove; such a tool doesn't exist today. The
elements in trove-integration don't really count since they are largely
developed for Ubuntu only, inject Trove guestagent src from git only,
and, beyond MySQL 5.6, are not tested by the gate.

>
>> There's someone willing to do the job and spend sometime doing the
>> research.
>> This same person will provide feedback in addition to the one already
>> provided
>> in [1].
>>
>> Sorry for not providing much technical details now but I did want to
>> share the
>> above. Thanks for starting this thread, I believe this discussion in the
>> ML will
>> be beneficial.
>>
>> Flavio
>>
>>> Thanks,
>>>
>>> -amrith
>>>
>>>
>>> [1] https://review.openstack.org/#/c/295274/
>>> [2] http://docs.openstack.org/developer/trove/dev/building_guest_images.html
>>> [3] https://git.openstack.org/cgit/openstack/diskimage-builder/tree/README.rst#writing-an-element
>>> [4] http://git.openstack.org/cgit/openstack/trove-integration/tree/scripts/redstack
>>> [5] http://git.openstack.org/cgit/openstack/trove-integration/tree/scripts/files/trove-guest.systemd.conf
>>> [6] http://git.openstack.org/cgit/openstack/trove-integration/tree/scripts/files/trove-guest.upstart.conf
>>>
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>> --
>> @flaper87
>> Flavio Percoco
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