Re: [nfs-utils PATCH] nfs4id: a tool to create and persist nfs4 client uniquifiers

[Trond Myklebust <trondmy@hammerspace.com>]

On Thu, 2022-02-10 at 08:21 +1100, NeilBrown wrote:
> On Wed, 09 Feb 2022, Steve Dickson wrote:
> > 
> > On 2/8/22 11:22 AM, Benjamin Coddington wrote:
> > > On 8 Feb 2022, at 11:04, Steve Dickson wrote:
> > > 
> > > > Hello,
> > > > 
> > > > On 2/4/22 7:56 AM, Benjamin Coddington wrote:
> > > > > The nfs4id program will either create a new UUID from a
> > > > > random source or
> > > > > derive it from /etc/machine-id, else it returns a UUID that
> > > > > has already
> > > > > been written to /etc/nfs4-id.  This small, lightweight tool
> > > > > is 
> > > > > suitable for
> > > > > execution by systemd-udev in rules to populate the nfs4
> > > > > client 
> > > > > uniquifier.
> > > > > 
> > > > > Signed-off-by: Benjamin Coddington <bcodding@redhat.com>
> > > > > ---
> > > > >   .gitignore               |   1 +
> > > > >   configure.ac             |   4 +
> > > > >   tools/Makefile.am        |   1 +
> > > > >   tools/nfs4id/Makefile.am |   8 ++
> > > > >   tools/nfs4id/nfs4id.c    | 184
> > > > > +++++++++++++++++++++++++++++++++++++++
> > > > >   tools/nfs4id/nfs4id.man  |  29 ++++++
> > > > >   6 files changed, 227 insertions(+)
> > > > >   create mode 100644 tools/nfs4id/Makefile.am
> > > > >   create mode 100644 tools/nfs4id/nfs4id.c
> > > > >   create mode 100644 tools/nfs4id/nfs4id.man
> > > > Just a nit... naming convention... In the past
> > > > we never put the protocol version in the name.
> > > > Do a ls tools and utils directory and you
> > > > see what I mean....
> > > > 
> > > > Would it be a problem to change the name from
> > > > nfs4id to nfsid?
> > > 
> > > Not at all.. 
> > Good...
> > 
> > > and I think there's a lot of room for naming discussions about
> > > the file to store the id too:
> > > 
> > > Trond sent /etc/nfs4_uuid
> > > Neil suggests /etc/netns/NAME/nfs.conf.d/identity.conf
> > > Ben sent /etc/nfs4-id (to match /etc/machine-id)
> > Question... is it kosher to be writing /etc which is
> > generally on the root filesystem?
> > 
> > By far Neil suggestion is the most intriguing... but
> > on the containers I'm looking at there no /etc/netns
> > directory.
> > 
> > I had to install the iproute package to do the
> > "ip netns identify" which returns NULL...
> > also adds yet another dependency on nfs-utils.
> > 
> > So if "ip netns identify" does return NULL what directory
> > path should be used?
> 
> I'm not sure if this has been explicitly answered or not, so just in
> case... 
>   if "ip netns/identify" report NAME, then use /etc/netns/NAME/foo
>   if it fails or report nothing, use /etc/foo
> 
> I think this is required whether we use nfs4-id, nfs-id, nfs-
> identity,
> nfs.conf.d/identity.conf or any other file in /etc.
> 

Who uses this tool, and for what? This isn't anything that the standard
container orchestration managers use.

I'm running docker right now:

NR_09-21:41:07 host ~ $ ls /etc/net*
/etc/netconfig  /etc/networks
NR_09-21:41:47 hosts ~ $ docker exec -it f7debc079f4e bash
[root@f7debc079f4e /]# ls /etc/net*
/etc/netconfig  /etc/networks
[root@f7debc079f4e /]# ip netns identify

[root@f7debc079f4e /]# 

As you can see, neither the host nor the container have anything in
/etc/netns, and 'ip netns identify' is drawing a blank in both.

-- 
Trond Myklebust
Linux NFS client maintainer, Hammerspace
trond.myklebust@hammerspace.com