[openstack-dev] [Ironic] Adding vendor drivers in Ironic

Gary Kotton gkotton at vmware.com
Sun Mar 1 10:32:37 UTC 2015

I am just relaying pain-points that we encountered in neutron. As I have
said below it makes the development process a lot quicker for people
working on external drivers. I personally believe that it fragments the
community and feel that the external drivers loose the community
contributions and inputs.

On 2/28/15, 7:58 PM, "Clint Byrum" <clint at fewbar.com> wrote:

>I'm not sure I understand your statement Gary. If Ironic defines
>what is effectively a plugin API, and the vendor drivers are careful
>to utilize that API properly, the two sets of code can be released
>entirely independent of one another. This is how modules work in the
>kernel, X.org drivers work, and etc. etc. Of course, vendors could be
>irresponsible and break compatibility with older releases of Ironic,
>but that is not in their best interest, so I don't see why anybody would
>need to tightly couple.
>As far as where generic code goes, that seems obvious: it all has to go
>into Ironic and be hidden behind the plugin API.
>Excerpts from Gary Kotton's message of 2015-02-28 09:28:55 -0800:
>> Hi,
>> There are pros and cons for what you have mentioned. My concern, and I
>>mentioned them with the neutron driver decomposition, is that we are are
>>loosing the community inputs and contributions. Yes, one can certainly
>>move faster and freer (which is a huge pain point in the community). How
>>are generic code changes percolated to your repo? Do you have an
>>automatic CI that detects this? Please note that when itonic release you
>>will need to release your repo so that the relationship is 1:1...
>> Thanks
>> Gary
>> From: Ramakrishnan G
>><rameshg87.openstack at gmail.com<mailto:rameshg87.openstack at gmail.com>>
>> Reply-To: OpenStack List
>><openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.o
>> Date: Saturday, February 28, 2015 at 8:28 AM
>> To: OpenStack List
>><openstack-dev at lists.openstack.org<mailto:openstack-dev at lists.openstack.o
>> Subject: [openstack-dev] [Ironic] Adding vendor drivers in Ironic
>> Hello All,
>> This is about adding vendor drivers in Ironic.
>> In Kilo, we have many vendor drivers getting added in Ironic which is a
>>very good thing.  But something I noticed is that, most of these reviews
>>have lots of hardware-specific code in them.  This is something most of
>>the other Ironic folks cannot understand unless they go and read the
>>hardware manuals of the vendor hardware about what is being done.
>>Otherwise we just need to blindly mark the file as reviewed.
>> Now let me pitch in with our story about this.  We added a vendor
>>driver for HP Proliant hardware (the *ilo drivers in Ironic).  Initially
>>we proposed this same thing in Ironic that we will add all the hardware
>>specific code in Ironic itself under the directory drivers/modules/ilo.
>>But few of the Ironic folks didn't agree on this (Devananda especially
>>who is from my company :)). So we created a new module proliantutils,
>>hosted in our own github and recently moved it to stackforge.  We gave a
>>limited set of APIs for Ironic to use - like get_host_power_status(),
>>set_host_power(), get_one_time_boot(), set_one_time_boot(), etc. (Entire
>>list is here 
> cyIvavSV
>> We have only seen benefits in doing it.  Let me bring in some examples:
>> 1) We tried to add support for some lower version of servers.  We could
>>do this without making any changes in Ironic (Review in proliantutils
>> 2) We are adding support for newer models of servers (earlier we use to
>>talk to servers in protocol called RIBCL, newer servers we will use a
>>protocol called RIS) - We could do this with just 14 lines of actual
>>code change in Ironic (this was needed mainly because we didn't think we
>>will have to use a new protocol itself when we started) -
>> Now talking about the advantages of putting hardware-specific code in
>> 1) It's reviewed by Openstack community and tested:
>> No. I doubt if I throw in 600 lines of new iLO specific code that is
>>T_aIhtw0oZPK4tFHGnlcbBH6wac&e=>) for Ironic folks, they will hardly take
>>a look at it.  And regarding testing, it's not tested in the gate unless
>>we have a 3rd party CI for it.  [We (iLO drivers) also don't have 3rd
>>party CI right now, but we are working on it.]
>> 2) Everything gets packaged into distributions automatically:
>> Now the hardware-specific code that we add in Ironic under
>>drivers/modules/<vendor>/ will get packaged into distributions, but this
>>code in turn will have dependencies  which needs to be installed
>>manually by the operator (I assume vendor specific dependencies are not
>>considered by Linux distributions while packaging Openstack Ironic).
>>Anyone installing Ironic and wanting to manage my company's servers will
>>again need to install these dependencies manually.  Why not install the
>>wrapper if there is one too.
>> I assume we only get these advantages by moving all of
>>hardware-specific code to a wrapper module in stackforge and just
>>exposing some APIs for Ironic to use:
>> * Ironic code would be much cleaner and easier to maintain
>> * Any changes related to your hardware - support for newer hardware,
>>bug fixes in particular models of hardware, would be very easy. You
>>don't need to change Ironic code for that. You could just fix the bug in
>>your module, release a new version and ask your users to install a newer
>>version of the module.
>> * python-fooclient could be used outside Ironic to easily manage foo
>> * Openstack CI for free if you are in stackforge - unit tests, flake
>>tests, doc generation, merge, pypi release everything handled
>> I don't see any disadvantages.
>> Now regarding the time taken to do this, if you have all the code ready
>>now in Ironic (which assume you will already have), perhaps it will take
>>a day to do this - half a day for putting into a separate module in
>>python/github and half a day for stackforge. The request to add
>>stackforge should get approved in the same day (if everything is
>> Let me know all of your thoughts on this.  If we agree, I feel we
>>should have some documentation on it in our Ironic docs directory.
>> Thanks for reading :)
>> Regards,
>> Ramesh
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