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Requests for Discussion
Writing down ideas for system enhancement while they are still nascent allows for important, actionable technical discussion. We capture these in Requests for Discussion, which are documents in the original sprit of the IETF Request for Comments, as expressed by RFC 3:
The content of a note may be any thought, suggestion, etc. related to the software or other aspect of the network. Notes are encouraged to be timely rather than polished. Philosophical positions without examples or other specifics, specific suggestions or implementation techniques without introductory or background explication, and explicit questions without any attempted answers are all acceptable. The minimum length for a note is one sentence.
These standards (or lack of them) are stated explicitly for two reasons. First, there is a tendency to view a written statement as ipso facto authoritative, and we hope to promote the exchange and discussion of considerably less than authoritative ideas. Second, there is a natural hesitancy to publish something unpolished, and we hope to ease this inhibition.
The philosophy of our Requests for Discussion is exactly this: timely rather than polished, with the immediate idea of promoting technical discussion. Over time, we expect that this discussion will often converge on an authoritative explanation of new functionality -- but it's entirely acceptable for an RFD to serve only as a vector of discussion. (We use the term "Requests for Discussion" in lieu of "Requests for Comments" to avoid conflation with the IETF construct -- and the more formal writing that it has come to represent.)
RFDs
Contents of an RFD
The following is a way to help you think about and structure an RFD document. This includes some things that we think you might want to include. If you're unsure if you need to write an RFD, here are some occasions where it usually is appropriate:
- Adding new endpoints to an API or creating an entirely new API
- Adding new commands or adding new options
- Changing the behaviour of endpoints, commands, APIs
- Otherwise changing the implementation of a component in a significant way
- Something that changes how users and operators interact with the overall system.
- Changing the way that software is developed or deployed
- Changing the way that software is packaged or operated
- Otherwise changing the way that software is built
This is deliberately broad; the most important common strain across RFDs is that they are technical documents describing implementation considerations of some flavor or another. Note that this does not include high-level descriptions of desired functionality; such requests should instead phrased as Requests for Enhancement.
RFDs start as a simple markdown file that use a bit of additional metadata to describe its current state. Every RFD needs a title that serves as a simple synopsis of the document. (This title is not fixed; RFDs are numbered to allow the title to change.) In general, we recommend any initial RFD address and/or ask the following questions:
Title
This is a simple synopsis of the document. Note, the title is not fixed. It may change as the RFD evolves.
What problem is this solving?
The goal here is to describe the problems that we are trying to address that motivate the solution. The problem should not be described in terms of the solution.
What are the principles and constraints on the design of the solution?
You should use this section to describe the first principles or other important decisions that constrain the problem. For example, a constraint on the design may be that we should be able to do an operation without downtime.
How will users interact with these features?
Here, you should consider both operators, end users, and developers. You should consider not only how they'll verify that it's working correctly, but also how they'll verify if it's broken and what actions they should take from there.
What repositories are being changed, if known?
If it's known, a list of what git repositories are being changed as a result of this would be quite useful.
What public interfaces are changing?
What interfaces that users and operators are using and rely upon are changing? Note that when changing public interfaces we have to be extra careful to ensure that we don't break existing users and scripts.
What private interfaces are changing?
What interfaces that are private to the system are changing? Changing these interfaces may impact the system, but should not impact operators and users directly.
What is the upgrade impact?
For an existing install, what are the implications if anything is upgraded through the normal update mechanisms, e.g. platform reboot, sdcadm update, manta-adm update, etc. Are there any special steps that need to be taken or do certain updates need to happen together for this
What is the security impact?
What (untrusted) user input (including both data and code) will be used as part of the change? Which components will interact with that input? How will that input be validated and managed securely? What new operations are exposed and which privileges will they require (both system privileges and Triton privileges)? How would an attacker use the proposed facilities to escalate their privileges?
Mechanics of an RFD
To create a new RFD, you should do the following steps.
Allocate a new RFD number
RFDs are numbered starting at 1, and then increase from there. When you start, you should allocate the next currently unused number. Note that if someone puts back to the repository before you, then you should just increase your number to the next available one. So, if the next RFD would be number 42, then you should make the directory 0042 and place it in the file 0042.md. Note, that while we use four digits in the directories and numbering, when referring to an RFD, you do not need to use the leading zeros.
$ mkdir -p rfd/0042
$ cp prototypes/prototype.md rfd/0042/README.md
$
Write the RFD
At this point, you should write up the RFD. Any files that end in *.md
will automatically be rendered into HTML and any other assets in that
directory will automatically be copied into the output directory.
RFDs should have a default text width of 80 characters. Any other materials related to that RFD should be in the same directory.
RFD Metadata and State
At the start of every RFD document, we'd like to include a brief amount of metadata. The metadata format is based on the python-markdown2 metadata format. It'd look like:
---
authors: Han Solo <han.solo@shot.first.org>, Alexander Hamilton <ah@treasury.gov>
state: draft
---
We keep track of two pieces of metadata. The first is the authors, the
second is the state. There may be any number of authors, they should
be listed with their name and e-mail address.
Currently the only piece of metadata we keep track of is the state. The state can be in any of the following. An RFD can be in one of the following four states:
- predraft
- draft
- publish
- abandoned
While a document is in the predraft state, it indicates that the work is
not yet ready for discussion, but the RFD is effectively a placeholder.
Documents under active discussion should be in the draft state. Once
(or if) discussion has converged and the document has come to reflect
reality rather than propose it, it should be updated to the publish
state.
Note that just because something is in the publish state does not
mean that it cannot be updated and corrected. See the "Touching up"
section for more information.
Finally, if an idea is found to be non-viable (that is, deliberately never
implemented) or if an RFD should be otherwise indicated that it should
be ignored, it can be moved into the abandoned state.
Start the discussion
Once you have reached a point where you're happy with your thoughts and notes, then to start the discussion, you should first make sure you've pushed your changes to the repository and that the build is working.
From here, send an e-mail to the appropriate mailing list that best fits your work. The options are:
- sdc-discuss@lists.smartdatacenter.org
- manta-discuss@lists.mantastorage.org
- smartos-discuss@lists.smartos.org
The subject of the message should be the RFD number and synopsis. For
example, if you RFD number 169 with the title Overlay Networks for Triton,
then the subject would be RFD 169 Overlay Networks for Triton.
In the body, make sure to include a link to the RFD.
If an RFD is in the predraft or draft state, you should also open an
issue to allow for additional
opportunity for discussion of the RFD. This issue should have the synopsis
that reflects its purpose (e.g. "RFD 169: Discussion") and the body should
explain its intent (e.g. "This issue represents an opportunity for discussion
of RFD 169 while it remains in a pre-published state."). Moreover, a
discussion field should be added to the RFD metadata, with a URL that
points to an issue query for the RFD number. For example:
---
authors: Chewbacca <chewie77@falcon.org>
state: draft
discussion: https://github.com/joyent/rfd/issues?q="RFD+169"
---
When the RFD is transitioned into the publish state, the discussion issue
should be closed with an explanatory note (e.g. "This RFD has been published
and while additional feedback is welcome, this discussion issue is being
closed."), but the discussion link should remain in the RFD metadata.
Note that discussion might happen via more than one means; if discussion is being duplicated across media, it's up to the author(s) to reflect or otherwise reconcile discussion in the RFD itself. (That is, it is the RFD that is canonical, not necessarily the discussion which may be occurring online, offline, in person, over chat, or wherever human-to-human interaction can be found.)
Finishing up
When discussion has wrapped up and the relevant feedback has been
incorporated, then you should go ahead and change the state of the
document to publish and push that change.
Touching up
As work progresses on a project, it may turn out that our initial ideas and theories have been disproved or other architectural issues have come up. In such cases, you should come back and update the RFD to reflect the final conclusions or, if it's a rather substantial issue, then you should consider creating a new RFD.
Contributing
Contributions are welcome, you do not have to be a Joyent employee to submit an RFD or to comment on one. The discussions for RFDs happen on the open on the various mailing lists related to Triton, Manta, and SmartOS.
To submit a new RFD, please provide a git patch or a pull request that consists of a single squashed commit and we will incorporate it into the repository or feel free to send out the document to the mailing list and as we discuss it, we can work together to pull it into the RFD repository.