On Fri, Jan 20, 2023 at 03:33:21PM +0000, Norman Gray wrote:
Ondřej, hello.
On 20 Jan 2023, at 10:47, Ondřej Kuzník wrote:
That said, patches implementing some kind of SRV are welcome. The easiest way might be to introduce an lloadd tier implementation that manages its backend collection accordingly.
It's not an OpenLDAP patch, but I've attached a module which might be of interest here. This exposes a function
char* get_sorted_srv_records(const char* domain);which does a SRV lookup, and orders the records that come back according to the specification of RFC 2782 (though in a single pass, rather than the clumsy multiple pass algorithm that the RFC suggests).
Hi Norman, DNS retrieval and parsing of SRV records is the easy part, and libevent has code to help us with that already. It's the management of the backends on the tier (shutting down those that aren't listed anymore, adding those that are new, rearranging the lists) all while the server is still running unless we request a full server pause for it. And any of the backends being removed might still have pending operations, what do we do with those?
And then the code that uses those levels and weights for each request that comes in, in an efficient way. But a lot of that is in lloadd (tier "weighted") and/or libldap already.
All of this is managed if you have another process that manipulates cn=config for you and it can make some of those decisions as appropriate for your own deployment.
Regards,