[Freeipa-devel] [PATCH 0044] Periodically refresh global ipa-kdb configuration

[Alexander Bokovoy]

On Thu, 01 May 2014, Nathaniel McCallum wrote:
>On Tue, 2014-03-11 at 11:09 -0400, Simo Sorce wrote:
>> On Tue, 2014-03-11 at 16:05 +0200, Alexander Bokovoy wrote:
>> > On Tue, 11 Mar 2014, Jan Pazdziora wrote:
>> > >On Mon, Feb 24, 2014 at 02:26:27PM -0500, Nathaniel McCallum wrote:
>> > >> Before this patch, ipa-kdb would load global configuration on startup
>> > >> and never update it. This means that if global configuration is changed,
>> > >> the KDC never receives the new configuration until it is restarted.
>> > >>
>> > >> This patch enables caching of the global configuration with a timeout of
>> > >> 60 seconds.
>> > >>
>> > >> https://fedorahosted.org/freeipa/ticket/4153
>> > >
>> > >> >From 7daeae56671d7b3049b0341aad66c96877431bbe Mon Sep 17 00:00:00 2001
>> > >> From: Nathaniel McCallum <npmccallum at redhat.com>
>> > >> Date: Mon, 24 Feb 2014 14:19:13 -0500
>> > >> Subject: [PATCH] Periodically refresh global ipa-kdb configuration
>> > >>
>> > >> Before this patch, ipa-kdb would load global configuration on startup and
>> > >> never update it. This means that if global configuration is changed, the
>> > >> KDC never receives the new configuration until it is restarted.
>> > >>
>> > >> This patch enables caching of the global configuration with a timeout of
>> > >> 60 seconds.
>> > >>
>> > >> https://fedorahosted.org/freeipa/ticket/4153
>> > >
>> > >I have only read the code and it looks sane, so depending on how much
>> > >you consider my word about code-reading worth, ack.
>> > >
>> > >However, my gut feeling is that my preferred way of handling the issue
>> > >(without knowing much about the background of the ticket) would
>> > >probably be a HUP signal handler or something similar, rather than
>> > >polling for current values with the value timeout. This patch
>> > >introduces small nondeterminism to the behaviour when the usage of the
>> > >new values cannot really be enfoced by the admin (without the daemon
>> > >restart).
>> > Thing is, we need the update to happen when other, non-root process
>> > makes the changes -- in our case when IPA server running under httpd
>> > privileges performs series of MS-RPC calls towards smbd which lead to
>> > creating certain LDAP objects. httpd couldn't send SIGHUP to a process
>> > not owned by httpd's effective user (non-root).
>>
>> Yes but this is not really the way to go.
>>
>> The proper fix is to use syncrepl/persistent search to get a
>> notification of when we need to reload the configuration.
>>
>> On the patch itself I have a NACK due to this syntax used in various
>> places: function()->attribute
>>
>> don't. do. that. ever.
>>
>> assign whatever come from the function to a local variable and *check*
>> it is not null, *then* use it.
>
>Attached patch fixes the NACK issue, but does not address the question
>of the larger approach. Do we need to take a different approach? If so,
>what is it?

I've tested the patch but was unable to spot any activity to refresh the
configuration after I've updated it with 
    ipa config-mod --ipaconfigstring=KDC:Disable\ Lockout

At least, dirsrv logs didn't show me any attempt to re-read IPA config
past the change.

>
>Nathaniel


-- 
/ Alexander Bokovoy