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Re: Is existing documentation kind of vague?
On Fri, 2017-11-17 at 08:27 +0200, MJ J wrote:
> No matter how you wrap poll() and select(), they will always be
> poll()
> and select() - you will always run loops around an ever increasing
> stack of file descriptors while doing I/O. BDB is always going to
> have
> the same old problems... That's what I'm talking about - sacrificing
> performance for platform portability (NSPR).
>
> FreeIPA could be multi-tenant i.e.support top-level and subordinate
> kerberos realms if it supported a more sensible DIT layout. I know
> because I have built such a system (based on OpenLDAP) and deployed
> it
> internationally. Probably the best piece of code to come out of the
> project is bind-dyndb-ldap.
Whoa mate - I'm not here to claim that 389 is a better ldap server - we
just do some different things. We acknowledge our limitations and are
really working on them and paying down our tech debt. We want to remove
parts of nspr, replace bdb and more. :)
I'm here to follow the progress of the openldap project, who have a
team of people I respect greatly and want to learn from, and here to
help discussions and provide input from a different perspective.
There are things that today openldap does much better than us for
certain - and there are also some things that we do differently too
like DNA plugin uid allocation, replication etc,
There are also project focusses and decisions made to improve
supportability in systems like FreeIPA - we can discuss them forever,
but reality is today, FreeIPA is not targeting multi-tennant
environments because the majority of our consumers don't want that
functionality. We made a design decision and have to live with it. I'm
providing this information to help give the ability for people to
construct an informed opinion.
As mentioned, I'm not here to throw insults and criticisms, I'm here to
have positive, respectful discussions about technology, to provide
different ideas, and to learn from others :)
Thanks,
>
> On Fri, Nov 17, 2017 at 4:49 AM, William Brown <wibrown@redhat.com>
> wrote:
> > On Thu, 2017-11-16 at 05:54 +0200, MJ J wrote:
> > > Sure, it can be improved to become invulnerable to the
> > > academically
> > > imaginative race conditions that are not going to happen in real
> > > life.
> > > That will go to the very bottom of my list of things to do now,
> > > thanks.
> > >
> > > FreeIPA is a cool concept, too bad it's not scalable or multi-
> > > tenant
> > > capable.
> >
> > It's a lot more scalable depending on which features you
> > enable/disable. It won't even be multi-tenant due to the design
> > with
> > gssapi/krb.
> >
> > At the end of the day, the atomic UID/GID alloc in FreeIPA is from
> > the
> > DNA plugin from 389-ds-base (which you can multi-instance on a
> > server
> > or multi-tentant with many backends). We use a similar method to AD
> > in
> > that each master has a pool of ids to alloc from, and they can
> > atomically request pools. This prevents the race issues you are
> > describing here with openldap.
> >
> > So that's an option for you, because those race conditions *do* and
> > *will* happen, and it will be a bad day for you when they do.
> >
> >
> > Another option is an external IDM system that allocs the uid's and
> > feeds them to your LDAP environment instead,
> >
> > Full disclosure: I'm a core dev of 389 directory server, so that's
> > why
> > I'm speaking in this context. Not here to say bad about openldap or
> > try
> > to poach you, they are a great project, just want to offer
> > objective
> > insight from "the other (dark?) side". :)
> >
> > >
> > > On Wed, Nov 15, 2017 at 11:09 PM, Michael Ströder <michael@stroed
> > > er.c
> > > om> wrote:
> > > > MJ J wrote:
> > > > > TLDR; in a split-brain situation, you could run into trouble.
> > > > > But
> > > > > this
> > > > > isn't the only place. Efffective systems monitoring is the
> > > > > key
> > > > > here.
> > > > >
> > > > > Long answer;
> > > > > [..]
> > > > > The solution I posted has been in production in a large,
> > > > > dynamic
> > > > > company for several years and never encountered a problem.
> > > >
> > > > Maybe it works for you. But I still don't understand why you
> > > > post
> > > > such a
> > > > lengthy justification insisting on your MOD_INCREMENT / read-
> > > > after-
> > > > write
> > > > approach with possible race condition even in a single master
> > > > deployment
> > > > while there are two proper solutions with just a few lines code
> > > > more:
> > > >
> > > > 1. delete-by-value to provoke a conflict like the original
> > > > poster
> > > > mentioned by pointing to
> > > > http://www.rexconsulting.net/ldap-protocol-uidNumber.html
> > > >
> > > > 2. MOD_INCREMENT with pre-read control
> > > >
> > > > Of course none of the solutions work when hitting multiple
> > > > providers
> > > > hard in a MMR setup or in a split-brain situation. One has to
> > > > choose a
> > > > "primary" provider then.
> > > > BTW: AFAIK with FreeIPA each provider has its own ID range to
> > > > prevent that.
> > > >
> > > > Ciao, Michael.
> > >
> > >
> >
> > --
> > Sincerely,
> >
> > William Brown
> > Software Engineer
> > Red Hat, Australia/Brisbane
> >
>
>
--
Sincerely,
William Brown
Software Engineer
Red Hat, Australia/Brisbane