Networking with Upstart and sysvinit scripts

[Steve Langasek]

Hi Christian,

On Sat, Jan 28, 2012 at 01:49:06PM +0100, Christian Roessner wrote:
> > This is fixed in Ubuntu 11.10 and later.

> > https://bugs.launchpad.net/ubuntu/+source/dhcp3/+bug/580319

> > We do not boot to runlevel 2 unless either all "auto" interfaces from
> > /etc/network/interfaces are up, or 120 seconds have passed since lo
> > was brought up. This gives ample time for any DHCP or heavy static
> > configurations/bridge/bonded/etc configurations to finish, but will
> > continue the boot in case you have listed an interface there that is
> > broken or will never come up.

> That is really great to hear! I really was afraid, how this would continue
> in future releases.  For me, this sounds like a great idea with the
> runlevel/120s thing.

> What I miss in interfaces is a better ipv6 support. I find it somewhat
> weird to configure multiple addresses like this:

> iface eth0:0 inet6 static
>  # mail.roessner-net.de
>  address   2a01:4f8:131:1081:88:198:80:230
>  netmask   64

I also find it weird that you're doing this. :-)  

> There are several things that are not optimal. IPv6 are not aliases. A
> second way of configuring them was to add post-up stuff.

Yes, I think an 'ip addr' command in the post-up would be more natural here.
*Ideally* you would be able to specify multiple ipv6 addresses for a single
interface stanza in /etc/network/interfaces.

> I know, this might look like off-topic, but network configuration is part
> of Upstart and if the basic configuration makes trouble, you will have
> problems n the whole boot process.

This really isn't part of upstart; it's part of ifupdown, which is unrelated
(though integrated, on Ubuntu).  Upstart-using systems not derived from
Debian are likely to use a completely different method of configuring
network devices.

Not to say we can't discuss it here, but I don't think the ifupdown
maintainers are subscribed to this list, so this discussion is unlikely to
result in any changes to ifupdown behavior.

> So I would suggest to optimize network configuration in general.

> I have a dozen of configurations, even with bonding/vlan mixtures, where
> boot process is really critical.  Especially in the latter case, where you
> use bonding and stuff in HA setups.  If the boot process is not 100%
> stable, the whole HA is unstable.  And this on a LTS release.

Improving network stack reliability has been a major focus for the Ubuntu
12.04 LTS release, and I think users will be satisfied with the results.
Again, these were not really upstart issues per se - there've been race
conditions with boot-time networking ever since udev came around, it's just
that boot was slow enough that users rarely ran into them.  Upstart just
made the race windows much, much larger by speeding everything up.

> > Anyway, give 11.10 a try, its possible we will backport something to
> > lucid, but no guarantees, as its a rather large change in the way we
> > treat /etc/network/interfaces, and it has not been popular with everyone,
> > as there are some people abusing /etc/network/interfaces and this causes
> > their system to take 2 minutes extra too boot.

> I can not easily give 11.10 a try, because most systems are really
> production systems (and some of the customers do not have testing
> environments).  I only could give it a try on my own server, but then I
> would have to upgrade 11 servers at once, because they have a lot of
> dependencies with services to each other (postgres backport, LDAP
> nackport, ...).

> If there was a chance to have a backport package for 11.10, I could test
> it on individual servers and give feedback to you.  Even, if there was a
> testing PPA, I would test it for you, bt PLEASE do not force me for
> upgrades right now.  That really would be pain ;)

Unfortunately these networking fixes have deep interdependencies with other
changes to the core system since 10.04, so a backport is not likely.

-- 
Steve Langasek                   Give me a lever long enough and a Free OS
Debian Developer                   to set it on, and I can move the world.
Ubuntu Developer                                    http://www.debian.org/
slangasek at ubuntu.com                                     vorlon at debian.org
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 828 bytes
Desc: Digital signature
URL: <https://lists.ubuntu.com/archives/upstart-devel/attachments/20120131/a74859b8/attachment.pgp>