[arch-releng] [archiso] disable 80-net-name-slot.rules for next releng?

[Dave Reisner]

On Tue, May 28, 2013 at 03:42:19PM +0200, Thomas Bächler wrote:
> Am 25.05.2013 01:27, schrieb Gerardo Exequiel Pozzi:
> > On 05/24/2013 11:27 AM, Dave Reisner wrote:
> >> On Fri, May 24, 2013 at 11:04:24AM -0300, Gerardo Exequiel Pozzi wrote:
> >>> Hello
> >>>
> >>> I am planing to do a new release[#1] this weekend. Since we are using
> >>> dhcpcd.service (dhcp for all net-if) and is racy, sometimes net-if
> >>> rename work and others no. So I think can be a good idea to not rename
> >>> at all.
> >>>
> >>> Opinions?
> >>>
> >>> Thanks.
> >>>
> >>>
> >>> [#1] Includes the change to move mkarchiso to /usr/bin.
> >>> -- 
> >>> Gerardo Exequiel Pozzi
> >>> \cos^2\alpha + \sin^2\alpha = 1
> >>>
> >>
> >> I tend to think this will make for a lousy user experience given that
> >> interface names will potentially change on the first boot of the newly
> >> installed system. Not really in favor of this.
> >>
> >> Proposal: stop using dhcpcd.service, replace with a udev rule that
> >> launches instances of dhcpcd at .service for network devices as they
> >> appear:
> >>
> >>   # /etc/udev/rules.d/81-dhcpcd.rules
> >>   ACTION=="add", SUBSYSTEM=="net", ENV{SYSTEMD_WANTS}="dhcpcd@$env{INTERFACE}.service"
> >>
> >> This potentially breaks ordering for units on network.target, but we've
> >> never been able to guarantee that anyways using dhcpcd.service.
> >>
> >> d
> >>
> > 
> > Ouch! It does not work :(
> > 
> > Looks like interface at this point is still named eth0, you can see on
> > console at boot:
> > 
> > [  OK  ] Started Entropy Harvesting Daemon.
> >          Starting Initializes Pacman keyring...
> > [  OK  ] Started Login Service.
> >          Expecting device sys-subsystem-net-devices-eth0.device...
> > [  OK  ] Found device /dev/ttyS0.
> >          Starting Serial Getty on ttyS0...
> 
> I think the INTERFACE environment variable is set before the rename. We
> can probably fix this - maybe try $name instead of $env{INTERFACE}?
> 
> 

Good call, this seems to work. Tested as follows on a VM:

Added a rule to force a name change:

# /etc/udev/rules.d/80-net-name-slot.rules
SUBSYSTEM=="net", ACTION=="add", DRIVERS=="?*", ATTR{address}=="de:ad:be:ef:00:01", KERNEL=="eth*", NAME="lan0"

And then the rule to add SYSTEMD_WANTS with Thomas's suggestion:

# /etc/udev/rules.d/81-dhcpcd.rules
ACTION=="add", SUBSYSTEM=="net", ENV{SYSTEMD_WANTS}="dhcpcd@$name.service"

Reboot...

# systemctl show dhcpcd at lan0
dhcpcd at lan0.service - dhcpcd on lan0
   Loaded: loaded (/etc/systemd/system/dhcpcd at .service; disabled)
   Active: active (running) since Tue 2013-05-28 14:41:26 UTC; 2min 45s ago
   ....

# ip -4 a s lan0
2: lan0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
  inet 10.0.2.138/24 brd 10.0.2.255 scope global lan0
     valid_lft forever preferred_lft forever