cvs commit: src/etc/rc.d hostname
yar at comp.chem.msu.su
Tue Feb 13 07:04:41 UTC 2007
On Mon, Feb 12, 2007 at 09:03:33AM -0600, Brooks Davis wrote:
> On Mon, Feb 12, 2007 at 03:09:09PM +0300, Yar Tikhiy wrote:
> > On Sun, Feb 11, 2007 at 09:44:38PM -0600, Brooks Davis wrote:
> > > On Sun, Feb 11, 2007 at 11:53:17AM +0300, Yar Tikhiy wrote:
> > > > On Sat, Feb 10, 2007 at 08:52:28PM +0000, Ceri Davies wrote:
> > > > > On Sat, Feb 10, 2007 at 01:13:33PM +0000, Yar Tikhiy wrote:
> > > > > > yar 2007-02-10 13:13:33 UTC
> > > > > >
> > > > > > FreeBSD src repository
> > > > > >
> > > > > > Modified files:
> > > > > > etc/rc.d hostname
> > > > > > Log:
> > > > > > Handle the case when the admin forgot to set $hostname,
> > > > > > which can happen in new installations: advise to set the
> > > > > > variable and refer to rc.conf(5).
> > > > >
> > > > > Isn't it possible for the hostname to come via DHCP? How does this
> > > > > behave in that case (or rather, I can see how it behaves; is that the
> > > > > right thing)?
> > > >
> > > > I've never played with setting the hostname via DHCP. In my change,
> > > > I just tried not to break the existing code related to DHCP. Perhaps
> > > > someone using DHCP to get the hostname could shed light on the topic.
> > >
> > > This appears mostly harmless for systems that get their hostname via
> > > DHCP. They will get a warning, but it will otherwise work.
> > Now I see. The code getting $hostname via kenv from dhcp.host-name
> > is for the case when the host was booted via PXE. OTOH, a usual
> > DHCP client will run dhclient when it comes to setting up network
> > interfaces, i.e., after /etc/rc.d/hostname. Perhaps we need
> > a way to indicate that the hostname will be assigned automatically
> > and the nagging message shouldn't be emitted. E.g., in rc.conf:
> > hostname="DHCP"
> > I have no idea how many Unix hosts allow their hostname to be set
> > via DHCP. I prefer to think that a Unix host is like a good ship:
> > it never changes its name while furrowing the network seas. A DHCP
> > assigned hostname better fits crippled hosts such as diskless
> > stations etc.
> I wrote patches many years ago that added a "default_hostname" variable
> which acted like hostname except that dhclient-script knew about it and
> would change the host name to one it was give. This is the right thing
> to do IMO because many applications break horribly if hostname is not
OTOH, booting a DHCP-configured laptop without a network connection
can result in its not having the hostname set at all. This can
warrant making $hostname a mandatory variable even for DHCP clients.
dhclient will change the hostname if it gets a new value from the
server. Changing the default hostname to a DHCP value isn't worse
than changing the null hostname, so the former shouldn't break any
apps not broken yet. I mean that dhclient may do the change a bit
too late into the boot sequence if the DHCP server doesn't respond
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