James Carlson wrote:
> Perhaps I'm lost here, but I thought that milestone/single-user
> depends on milestone/network. Hence, if one of those things is
> waiting for a long time, the system just plain hangs. There's little
> useful work that can be done here.
I think this was changed in Jan's proposal as NWAM
is supposed to work in single user mode and milestone/
network is not required.
> I'm still uncomfortable with having SMF states that can hang waiting
> on activity that's outside of the local system. It makes some sense
> in some very narrow cases (e.g., no sense proceeding if you can't
> mount /usr because it's on a SAN and the interfaces for the SAN aren't
> running), but seems incorrect in general.
Well, if "network is the computer :-)" waiting for
the network seems natural ;-) Maybe in future,
all storage will be NAS.
>> No, I don't believe the intention of milestone/network is
>> about plumbing interface. It is about outside IP connectivity.
>
> OK, then, "plumbed and somehow configured."
I guess no. I don't think "plumbed and somehow
configured" implies external IP network connectivity.
> Nope. xntpd works fine with attached local clocks.
I suppose this is not what most customers expect xntpd
to work...
> You know this precisely when you receive packets from those nodes that
> are in response to packets you've sent. You don't know it at any
> other time.
This is why I said NWAM can detect "simple external IP
network connectivity."
> I think diagnosis of networking faults is a separate topic from the
> matter of configuring and using network interfaces.
I guess diagnosing network problem is probably a super set
of detecting network connectivity (well, simple network
connectivity in the sense that the machine can talk to
locally connected peers). But we are not concerned about
diagnosing network problems in general.
> It's certainly no less important -- I'd even argue that it may be more
> important -- but I'm not sure that it's something that NWAM is in a
> position to solve.
>
> Consider the typical sorts of user problems:
>
> - User forced Ethernet duplex to "full," which causes the switch to
> go (per the standards!) into "half," and causes lousy performance.
Yes, this is certainly outside NWAM. And I guess customers
won't expect milestone/network mean optimal performance.
> - User has /etc/nsswitch.conf and/or /etc/resolv.conf misconfigured,
> so that "ping -n" works and nothing else does.
I guess this is what Michael's future project will try to
solve. Yes, it is outside the first putback of NWAM.
> - User needs to have some routes, but doesn't know how to make the
> system add them. User can reach some hosts, but not others.
But will customers expect milestone/network to mean that there
is no such issue?
> - User should have DHCP enabled, but can't figure out how, or needs
> to turn it off, and can't.
>
> These are encountered time and again on just about every forum I watch
> where users can post. The last of those is something that NWAM should
> resolve, and the middle two might be made rarer by NWAM, but I don't
> think that all of them are completely avoided, nor do I see now NWAM
> makes diagnosis of the problem easier.
But I don't see why the above issues are related to the
current problem we are discussing. We need to define the
meaning of milestone/network and then decide if it is
actually a useful state for a machine.
>> I guess the basic question is whether external IP connectivity
>> is a useful state of the machine such that we need to make it
>> a milestone for other network services to depend on, both for
>> backward compatibility and for future usage. Comment?
>
> Given that it's something that I don't think we can in fact assert to
> be true, I don't think we should have such a state.
Suppose a machine can ping a router, and ping a host in
the same sub network, is it sufficient for most customers
that the machine has external IP connectivity?
--
K. Poon.
kacheong.poon at sun.com
