Subject: Re: [vserver] start-vservers patch
From: "Daniel Hokka Zakrisson" <daniel@hozac.com>
Date: Wed, 2 Feb 2011 04:04:20 +0100 (CET)

Jeff Jansen wrote:
> On Tuesday 01,February,2011 09:30 PM, Daniel Hokka Zakrisson wrote:
>> I still fail to see why you care what order they start in. If you don't
>> have explicit dependencies between them, i.e. you don't use depends, then
>> why does it matter? If you just set the number of parallel starts to
>> whatever number you want, that is the number that will be running at once,
>> all the time.
>
> Because some vservers are more "important" than others.  When a primary
> host node crashes and a secondary takes over, I want the important
> vservers to start up before the less important ones.

It sounds like you're doing it wrong. Why don't you fail-over on a
guest-by-guest basis?

> When I do a kernel upgrade on the hosts and switch the primary and
> secondary, I want the "important" vservers to shutdown last on one side
> and startup first on the other.  Then they are down for just a few
> seconds.  "Unimportant" vservers shutdown first and startup last.  They
> may be down for a couple of minutes.
>
> It's not that the machines "depend" on each other; it's that some are
> much more "mission-critical" than others.  I want the mail servers to
> come back first, for example.  Vservers running testing or development
> environments, however, should be started last.
>
> I don't want to leave this to alphabetical order by the config
> directory, which is what you get now.  I want to say that vserver 'C'
> should start first, vserver 'F' next, and so on.  No matter how many I
> start in parallel and no matter how long it takes for any individual
> machine to start, they will come up in this order.
>
> Obviously this isn't a felt need for your situation.  Many people
> probably agree with you.  When I asked about this on the list (over a
> year ago) only a few folks answered, and those who did said that they
> had worked out their own methods for starting vservers in a certain
> order.  I'm proposing a way to 'standardize' this so it doesn't have to
> be "worked out" again.
>
> But of course, if only a handful of folks actually need this, then it's
> a waste of time and an unnecessary complication to include it. Those of
> us who need it will continue to use our own methods.
>
> Jeff Jansen

-- 
Daniel Hokka Zakrisson