Creating users "on - the - fly"

Cary FitzHugh cary.fitzhugh at
Sat Feb 7 05:10:10 AEDT 2015

I guess I didn't want to litter the users table either - it just seems
"wrong" to be actually adding things to the host when it is really so
transient.  It feels like it should be LDAP-ish.  Just ask the server
for the keys and do a one-off authentication.  But I've seen even LDAP
creates the user directories.

I see that 2.6 kernels can have some 4B users, which should last me a
while.   But it is a bit more work and plumbing to try to keep things
in sync.

I'm a bit / very idealistic though - so I guess I'll keep rooting
around.  I'm ok writing a PAM module if that's what I needed.  But I
have a feeling there's a good bit more to it. And without someone know
"knows " - that can be a very long rabbit trail :)


On Fri, Feb 6, 2015 at 12:52 PM, Daniel Kahn Gillmor
<dkg at> wrote:
> On Fri 2015-02-06 12:41:38 -0500, Cary FitzHugh wrote:
>> The trouble is that the user isn't created on the machine beforehand.
>> But I actually don't want the user created, b/c I don't want to litter
>> all these servers with little user directories.    Users may be
>> transient as well - so littering the directories of these machines
>> with tons of data just causes many other problems (running out of
>> inodes, disk-space, etc).
> If this is your only concern, most systems don't require that a user
> have a unique home directory at all.  You could create a /home/nobody
> which is unusable by anyone, and populate the systems's user table with
> users (maybe via some sensible nameservice switch module) pointing at
> that directory as their homedir.
> In other words, i don't think this is an ssh problem, it can be solved
> directly in other parts of your OS.
>          --dkg

More information about the openssh-unix-dev mailing list