Re: cn=config: sharing, conditionals

[Jonathan Clarke <jonathan@phillipoux.net>]

On 27.05.2009 05:35, Howard Chu wrote:
> So, while we can fully replicate cn=config for the case where all 
> syncrepl participants are masters/peers, things are still a bit sticky 
> if we only want the replicas to remain in slave mode.
>
> Instead of going thru complicated mapping/virtual directory 
> redirections, it seems to me that all we need is to tag certain config 
> objects with the serverIDs to which they apply. As such, I'm 
> considering adding an olcServerMatch attribute to the 
> olcDatabaseConfig and olcOverlayConfig objectclasses. This would take 
> a regexp to match against the current server ID; if the pattern 
> matches then the config entry is processed otherwise it is ignored. 
> This attribute would be absent/empty by default, making the entry 
> always enabled.

I like the sound of this :)

Just one comment : consider automating configuration updates (via an 
administration interface or a script) - it would be easier to automate 
should the olcServerMatch attribute accept multiple values, to just add 
a value per serverID we want to match, instead of munging a single regexp.

Clearly, this could lead to a long list of values for setups with many 
different serverIDs, but lots of setups don't go that far.

My $0.02.

Regards,
Jonathan

> Likewise it may be useful to add a boolean olcDisabled attribute to 
> these classes, to allow databases and overlays to be switched on and 
> off without needing to delete them. Again, it would default to 
> absent/FALSE...
>
> We'd also want these controls for syncrepl stanzas. (Too bad the patch 
> to turn syncrepl into an overlay was never committed....)
>
> For example, we may have a cluster of servers in MMR with a pool of 
> other servers operating as slaves. We'd want the syncprov overlay 
> active on all of the masters, the syncrepl consumer active on all of 
> the servers, and the chain overlay active on all of the slaves. 
> Setting olcServerMatch on the syncprov and chain overlays would allow 
> things to behave as desired, without needing to create a parallel 
> config tree just for the slaves.
>
> Comments?


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Jonathan Clarke - jonathan@phillipoux.net
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Ldap Synchronization Connector (LSC) - http://lsc-project.org
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