[lvs-users] ldirectord feature patch - add abilility to signal system maintenance

[Sean Millichamp]

On Fri, 2009-05-15 at 09:37 +1000, Simon Horman wrote:

> On Thu, May 14, 2009 at 05:35:40PM -0400, Sean Millichamp wrote:
> > This patch adds the ability to notify ldirectord that a system should be
> > forced down for maintenance (or other reasons) even though the service
> > check passes.

> This looks good to me. Though I wonder if it might be
> better to save the results of ld_gethostbyaddr(), perhaps
> at initialisation time. Then again, perhaps not as that
> would stop ldirectord from respecting any DNS changes that
> may occur.

I briefly pondered that.  DNS already has opportunities for caching
external to ldirectord: you can run a local caching resolver with
appropriate TTLs or you can run nscd.  It seems like a lot of added
complexity for something which could be solved already in another way.

I suspect any site requiring the level of control this option provides
will have the ability and experience to know how to handle the DNS
lookup problem via a local caching resolver or nscd.  If this option
isn't enabled it becomes a non-issue as the DNS code never gets called.

Sean