[CentOS] "Site down for maintenance" - How is this accomplished?

[Matt Arnilo S. Baluyos (Mailing Lists)]

Thanks for the interesting insights everyone. I'll definitely look at
your suggestions.

And yes, the data center is off-site so that means the servers will be
on a different network.

On 8/25/07, Warren Young <warren at etr-usa.com> wrote:
> Brian Mathis wrote:
> >
> > Messing with DNS is really the wrong way to go on this.  You'd be
> > forcing all of the DNS servers involved to start messing with their
> > caches, update more frequently, etc.., pushing the problem out onto
> > "everyone else", and you have no control over any of it really.  Cache
> > time is only a suggestion, and not all DNS servers follow it.
>
> The only moral of this story is that you can't control everything.  That
> doesn't mean you shouldn't do what you can to speed the changeover.
>
> Temporarily lowering the DNS cache time for a server during a time of
> change is well established practice.  The only problem is that it'll
> increase the load on the primary name servers for that domain.  That's
> the best argument for it being temporary.
>
> > The way to go is to assign that same IP address to another box during
> > maintenance, and have that box show the page.
>
> The original poster did not explicitly say so, but the impression I got
> is that this "data center" is off-site, and possibly managed by a third
> party.  Letting multiple machines handle a single IP only works within a
> single physical site.  When multiple sites are involved, the only way to
> move an IP is to change global routing rules, which is more fraught with
> problems than the DNS change-over, which you already don't like.
>
> I guess theoretically you can have a single IP at multiple sites, with
> both routes being advertised as viable, but this will cause chaos as
> half the packets go one direction and half go the other.  "Don't cross
> the streams" indeed.


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