Re: my perspective on where we are with the single controller code base issue


David Meyer <dmm@...>
 

BTW, it has been pointed out that I mis-attributed the IOCTL idea to
Chris. That was my mistake. That said, the point I was making still
holds, namely, that there exist some ideas (and there will be more) to
deal with the near term deficiencies, perceived or otherwise, with the
SAL.

--dmm

On Tue, May 14, 2013 at 9:09 AM, David Meyer <dmm@...> wrote:
All,

As you know today (05.14.2013) was the day on which I wanted to
have the single controller code base issue resolved. What I had
said is that if we couldn't get the projects to agree on a way
forward that we as a TSC would vote on the issue. In the mean
time we have reached general consensus that the Dixon-Erickson
OpenDaylight Merged Controller Proposal (DE) (see
https://wiki.opendaylight.org/view/Dixon-Erickson_OpenDaylight_Merged_Controller_Proposal).
I want to be very clear here that that plan is distinct from what
is being called Proposed Dixon-Erickson Execution Plan (see
https://wiki.opendaylight.org/view/Proposed_Dixon-Erickson_Execution_Plan). So
from this perspective the community has come together over this
general direction. This functionally obviates the need for a
direct vote.

There have been quite a few concerns raised both publicly and to
me directly in private email. I'd like to review those here and
provide my perspective.

(i). The SAL

It is generally agreed that there is work left to be done on the
SAL, and that there may be instances in which, (in the near term)
we need a mechanism to provide a kind of "SAL bypass". Chris'
IOCTL proposal is one such idea. What I want to point out here is
the the ODP is evolving and as such we expect the architecture to
not not improve technically but converge on the needed
functionality/generality over time. This is a completely natural
state of affairs for any software project. The summary is that we
can provide short term mechanisms that bridge any perceived or
real functionality gaps in the SAL (again, Chris' IOCTL idea
might be one such mechanism). So while the OSCP folks have
argued pretty strongly against the SAL (both publicly and
privately), the DE proposal endorses the SAL concept and the
OpenDaylight Controller folks consider the SAL to be a
fundamental architectural construct. That said, evolution of the
SAL (be it the model driven approach, bypass, etc) is an issue
for folks who are writing SAL applications (committing code) to
resolve.

(ii). New Project/Repository

This issue is really about the fairness of commits to the
controller code base. This was stated explicitly to me privately
and publicly by Glenn Ricart and Guru Parulkar on the discuss
list. On the other hand, a simple majority of TSC members (and
many in the community) have expressed the opinion that they would
prefer moving forward with the plan outlined in the DE-proposal,
namely start with the OpenDaylight controller and evolve that as
needed. I will note here that there is no objective evidence that
there is a fairness issue with commits to any candiate code base
(it would hard for that to be the case in any event as we haven't
had the chance to really get going). Finally, since this is
largely a political issue it is outside of the scope of the TSC
and should be "policed" by the community.

As an aside, I will also note here that several community
members have expressed concern that the new project
approach is quite expensive and has little benefit beyond
the political/perception issue mentioned above.


(iii) Timing

The timing issue, namely that there is (is not) a rush to get the
ODP project up and running is one that has also been raised both
publicly and privately. I have been told (again, both publicly
and privately) by the OSCP (BSN) folks that they have time
pressure to port their applications to the ODP controller. That
is a principle rationale behind the Layered API proposal
(https://wiki.opendaylight.org/view/Layered_API_Merged_Controller_Proposal).
In addition, the same team is also arguing that we are in no rush and
in fact any date for resolving the controller issue is not only
artificial but damaging to the community; this exact sentiment was
contained in a private communication from Rob Sherwood to me dated
Tue, May 14, 2013 at 1:38 AM. In the spirit of transparency I am copying the
relevant text from that email here:

"I know that in your heart you believe what you're doing is the
right thing for the community, and that's why I've held off
making a stink, but as chair, I'm not sure what you're doing is
in terms of pushing hard on this artificial deadline (that you
said originally was not set in stone but now it is) or being
opaque in terms of the actual process is really helping the
community." -- Rob Sherwood to dmm on Tue, May 14, 2013 at 1:38
AM.

(this text of course also contains criticisms of me in my role
as chair to which I will return but I want to focus here on the
timing issue).

The summary here is that it has been argued by the OSCP team that
we accept their proposal
(https://wiki.opendaylight.org/view/File:LayeredAPIProposal.pdf)
because there is time pressure to port applications while at the
same time it is being argued that any time frame is damaging,
artificial, or worse. On the other hand, a simple majority of the
TSC have stated publicly (on the discuss list) that resolving the
controller code base issue of primary importance and they would
like to move forward with an interpretation of DE that starts
with the existing OpenDaylight controller code base.

It is clear from these inconsistencies that the timing issue is
largely a non-issue for the ODP community at large; in addition
there is clear benefit to moving forward with the DE approach now. One
might also note here that we've made very little progress over
the last many weeks and it is time to start, now.

(iv). Finally, if anyone has problems with me personally and/or the
way TSC is being run please air those publicly on the
discuss list. I will not be responding to emails such as the one
quoted above, lobbying by private phone call, or the
like. Again, if you have complaints about the way the TSC
is being run please discuss those on the discuss or tsc lists.

Summary: It is clear that there is additional evolution that is
needed for the SAL. No one is arguing otherwise. The new
project/repository issue is really about concern that commits
won't be fair (again, both Glenn and Guru raised this); however
there is no evidence that this is or will be the case and in any
event is not a technical issue and as such is out of scope for
the TSC. Finally, the timing issue is largely a commercial issue
(the need to port applications) and also has been argued on both
sides by the same people and as such I consider those arguments
largely moot; there is a real need to get the consortium going
(hence the date) but that is a wholly different argument.

--dmm

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