[ports/net/isc-dhcp*] Don't stop DHCP related daemons

Greg Byshenk freebsd at byshenk.net
Thu Sep 16 10:05:09 UTC 2010

On Wed, Sep 15, 2010 at 11:31:51AM -0700, Doug Barton wrote:
> On 9/15/2010 1:18 AM, Greg Byshenk wrote:
> >On Tue, Sep 14, 2010 at 06:22:24PM -0700, Doug Barton wrote:

> >>I can think of at least one more scenario off the top of my head. You
> >>want to run the new version of the service the next time the box is
> >>restarted for whatever reason, but the update is not so critical that it
> >>justifies restarting the system immediately.
> >
> >Do 'you' (generic) -really- want to do this?
> Once again, it's an area where the intelligence of the admin is expected 
> to be applied. :)  If you're thinking in terms of one machine, you're 
> right, this probably isn't a good idea. However if you're thinking of a 
> server farm with 1,000's of identical systems, a good QA process (so 
> it's a known-good change), and monitoring in place to detect a failed 
> reboot and take that box out of the pool; not only is what I described 
> reasonable, it's commonplace.

I don't want to belabor this too much, and -- of course -- the
intelligence of the sysadmin is expected to be applied, but part of
the point here is reasonable expectations of default behaviour.

It may be that my view of this is incomplete, but it really does seem
to me that the reasonable expectation is that an admin (of however many
machines) is updating service <X> because s/he wants to be -running-
the new version of service <X>. And that the most reasonable time to
change the running service from version a to version a+1 is during the
maintenance period in which the new service is installed. And this is
not dependent upon the distinction between working with a single server
or a pool of hundreds or thousands. After all, if the server is in its
maintenance window, then stopping/restarting the service won't make any
difference at that time, while it may at some other time.

That said, I can imagine cases in which one might wish to roll out a
new version but wait until some later time to activate it -- but it 
seems to me (at least) that these are the non-standard, 'special'
caes, and also the cases in which the admins can be expected to know
how to disable automatic updates/restarts.

Note: because of that last paragraph, I do think that any automated
restart of services should have the option to disable that restart.

greg byshenk  -  gbyshenk at byshenk.net  -  Leiden, NL

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