Re: [nfsv4] NFS over QUIC

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On Thu, Sep 3, 2020 at 5:53 PM Chuck Lever <chucklever@gmail.com> wrote:

>
>
> > On Sep 3, 2020, at 8:32 PM, Bruce Fields <bfields@fieldses.org> wrote:
> >
> > On Thu, Sep 03, 2020 at 07:48:19PM -0400, Chuck Lever wrote:
> >> Hi Bruce-
> >>
> >>> On Sep 3, 2020, at 5:52 PM, J. Bruce Fields <bfields@fieldses.org>
> wrote:
> >>>
> >>> I've been thinking about what might be required for NFS to run over
> >>> QUIC.
> >>>
> >>> Also cc'ing Steve French in case he's thought about this for CIFS/SMB.
> >>>
> >>> I don't have real plans.  For Linux, I don't even know if there's a
> >>> kernel QUIC implementation planned yet.
> >>>
> >>> QUIC uses TLS so we'd probably steal some stuff from the NFS/TLS draft:
> >>>
> >>>     https://datatracker.ietf.org/doc/draft-cel-nfsv4-rpc-tls/
> >>
> >> The link to the latest version of that document is
> >>
> >> https://datatracker.ietf.org/doc/draft-ietf-nfsv4-rpc-tls/
> >>
> >>> For example, section 4.3, which explains how to authenticate on top of
> >>> an already-encrypted session, should also apply to QUIC.
> >>
> >> Most of the document's content will be re-used for defining
> >> RPC-over-QUIC, for example the ALPN defined in Section 8.2.
> >> Lars Eggert, a chair of the QUIC WG, has been helping guide
> >> the RPC-over-TLS effort with an eye towards using QUIC for
> >> RPC when QUIC becomes more mature.
> >>
> >> I thought the plan was to write a specification of RPC-over-
> >> QUIC as a new RPC transport type with a netid and uaddr along
> >> with a definition of the transport semantics (a la TI-RPC).
> >> The document would need to explain record marking, peer
> >> authentication, how to use multi-path and multi-stream support,
> >> and so on.
> >>
> >> Making NFS work on that transport should then be straightforward
> >> enough that perhaps additional standards work wouldn't be
> >> necessary.
> >
> > Oh, OK, good.  Sounds like you're way ahead of me, then, I didn't know
> > there was a plan.
>
> That's all there is for the moment! :-)
>
>
> > --b.
> >
> >>> QUIC runs over UDP, so I think all that would be required to negotiate
> >>> support would be to attempt a QUIC connection to port 2049.
> >>>
> >>> The "Transport Layers" section in the NFS RFCs:
> >>>
> >>>     https://tools.ietf.org/html/rfc5661#section-2.9
> >>>
> >>> requires transports support reliable and in-order transmission, forbids
> >>> clients from retrying a request unless a connection is lost, and
> forbids
> >>> servers from dropping a request without closing a connection.  I'm
> still
> >>> vague on how those requirements interact with QUIC's connection
> >>> management and 0-RTT reconnection.
> >>>
> >>> https://www.ietf.org/id/draft-ietf-quic-applicability-07.txt looks
> >>> useful, as a guide for applications running over QUIC.  It warns that
> >>> connections can time out fairly quickly.  For timely callbacks over NFS
> >>> sessions, that means we need the client to ping the server regularly.
> >>> Sounds like that's what they do for HTTP/QUIC to make server push
> >>> notifications work:
> >>>
> >>>     https://tools.ietf.org/html/draft-ietf-quic-http-09#section-5
> >>>
> >>>     HTTP clients are expected to use QUIC PING frames to keep
> >>>     connections open.  Servers SHOULD NOT use PING frames to keep a
> >>>     connection open.  A client SHOULD NOT use PING frames for this
> >>>     purpose unless there are responses outstanding for requests or
> >>>     server pushes.
> >>>
> >>> QUIC allows multiple streams per connection--I wonder how we might use
> >>> that.  RFC 5661 justifies the requirement for an ordered transport
> with:
> >>>
> >>>     Ordered delivery simplifies detection of transmit errors, and
> >>>     simplifies the sending of arbitrary sized requests and responses
> >>>     via the record marking protocol.
> >>>
> >>> So as long as we don't try to split a single RPC among streams, I think
> >>> we're OK.  Would a stream per session slot be reasonable?  I'm not sure
> >>> what the cost of a stream is.
> >>>
> >>> Do we need to add a new universal address type so the protocol can
> >>> specify QUIC endpoints when necessary?  (For server-to-server-copy,
> pnfs
> >>> file layouts, fs_locations, etc.)  All QUIC needs is an IP address and
> >>> maybe a port, so maybe the existing UDP/TCP addresses are enough?
> >>
> >> --
> >> Chuck Lever
> >> chucklever@gmail.com
>
> --
> Chuck Lever
> chucklever@gmail.com
>
>
>
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