Re: Where does NM persists which connection is active? (Centos7)

[Dan Williams <dcbw redhat com>]

On Sun, 2016-09-11 at 23:45 +0300, Edward Haas wrote:
> On Sun, Sep 11, 2016 at 10:56 PM, Thomas Haller <thaller redhat com>
> wrote:
>
> > On Sun, 2016-09-11 at 15:45 +0300, Edward Haas wrote:
> > > Hello,
> > >
> > > Assuming there are multiple connection defined for an ethernet
> > > device
> > > and only a single one is active, how can I detect which ifcfg
> > > file
> > > was used for the connection?
> > >
> > > I cannot use nmcli for this, as NetworkManager is down at the
> > > moment
> > > I need the information.
> > > I just hope this info is available somewhere (as when starting
> > > NM,
> > > the correct connection is activated).
> > >
> > > Thanks,
> > > Edy.
> > Hi,
> >
> >
> > If NetworkManager is not running, there isn't a concept of "active
> > connection". What would that be?
> NM is defining multiple connection/ifcfg files, I hoped to have the
> last
> active one
> referenced somewhere.
> The fact that NM leaves multiple ifcfg files with autoconnect enabled
> is a
> problem,
> it is not a supported state for initscripts.

AFAIK it is supported just fine by the initscripts.  If you have
multiple NICs, every ifcfg that can be started (eg, ONBOOT=yes) will be
started.  You can also "ifup FOO; ifup BAR" and these will be active in
parallel.

What's less defined is what ifcfg file gets the default route and which
nameservers are used, but that's controlled by DEFROUTE=[yes/no] and
PEERDNS=[yes/no]...  in short, much more manual configuration when
using plain initscripts, but multiple autoconnect is definitely there.

Dan

> > When NM starts and the device has IP configuration, NM will pick a
> > connection that matches to what is currently configured on the
> > interface. In my opinion, that is a wrong thing, but that is what
> > currently happens. https://bugzilla.gnome.org/show_bug.cgi?id=74644
> > 0 is
> > supposed to improve on that, and it also will write a state-file
> > that
> > contains which connection was active on a device when
> > NetworkManager
> > stopped.
> Is this considered for back-porting to centos7/rhel7?
>
> When the device has no IP configuration at startup, NetworkManager
> will
> > autoconnect one of the available connections. Thereby it takes into
> > account connection.autoconnect-priority and connection.timestamp.
> >
> >
> > Maybe it would be helpful to explain what you are trying to do as
> > an
> > end-goal. If NetworkManager is not running, why would you want to
> > know
> > which connection was active when it stopped?
>
> > Thomas
>
> It is related to an oVirt node that is initially setup using Cockpit
> (through NM).
> Then, VDSM is installed and NM is disabled to avoid collisions.
> At this point, VDSM is required to acquire the last active ifcfg file
> and
> adjust it
> for VDSM.
> The problem is: There may be multiple such ifcfg files, so which one
> should
> be
> acquired and which should be just removed?
>
> This is actually an intermediate solution, I would prefer to either
> leave
> NM running
> and work with it, or ask it to 'ignore' devices.
> ifcfg is also something we should stop using directly.
> But all of these options won't happen in the immediate time frame,
> and we
> need
> something now.
>
> Thanks,
> Edy.
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