krb5-1.12 - New iprop features - tree propagation & slave notify

Nico Williams nico at
Wed Jan 15 14:55:02 EST 2014

On Wed, Jan 15, 2014 at 6:19 AM, Basch, Richard <Richard.Basch at> wrote:
> I just figured I would post an update since I managed to see slaves lagging in updates under high load (and wait the iprop interval). Currently, I post the initial notification, but it appears high-change environments still need more.
> My ideal would be to leave the notification async but if the notification fails, implement a parametized retry count before dropping the client.

It's only a ping, right?  So keep track of whether a slave was heard
from since pinging it and ping those not heard from again up to N
times more.  (Also, are you using RPC functions for the ping?  Are you
using the async interfaces?)

If there's a max latency tolerance you have to meet this isn't going
to do it.  You'll need something with closer to synchronous semantics
(e.g., go check all the slaves when you need to know if an update has
replicated) or actual sync semantics (the kadm5 operation does not
complete till all the slaves are updated).

> Personally, I am probably going to increase my ulog size since the 2500 restriction is gone (the kdc.conf man page was not updated to reflect such).

Of course :)  Make sure you're running 64-bit libkadm5srv consumers *only*.

Also, IMO the ulog design needs to be replaced.  It cannot handle very
large entries, for example.


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