[systemd-devel] Masking .network files

Sat Apr 5 08:06:29 PDT 2014

Hi,

On Sat, 5 Apr 2014 11:26:17 +0200
Tom Gundersen <teg at jklm.no> wrote:

> On Sat, Apr 5, 2014 at 12:43 AM, Leonid Isaev <lisaev at umail.iu.edu> wrote:
> >         I seem to have a strange issue with the way networkd processes its
> > configuration files. The machine is actually a systemd-nspawn container
> > with a static IP address, so I had to mask the default
> > 80-container-host0.network and create a custom config. Both real and
> > virtual machines are up-to-date archlinux [testing] installations.
> 
> So the best way to do this is to name your custom config file either
> the same as what you are overriding (if the overridden file should
> anyway never be used, which is the case for what you describe), or
> simply name it starting with a lower number. That way the first
> matching file will be applied.

Thanks for the explanation.

I figured that much, just wanted to know whether it was a 'feature'.

> 
> The 'masking' logic that you know from unit files does not really make
> much sense for .network files (but maybe this is something we should
> change...). Symlinks to /dev/null are just treated as empty .network
> files, so their meaning is "no [Match] section", which matches
> everything and "no [Network] section", which does nothing.

I don't know the grand goal of networkd, so it's just an opinion, but it seems
odd that the daemon will touch interfaces it shouldn't just because there is a
masked .network file (what if I want a given iface to stay down after boot).

> I suppose
> this may be used to express "ignore any subsequent .network files",
> but I doubt that is a particularly useful thing to do.

Wouldn't this be a bad thing? Because a distribution/upstream can break lots
of boxes by providing e.g. /usr/lib/systemd/network/30-stupid-default.network
which most people will automatically (and naively) mask...

Best,
L.

> 
> > -----
> > $ file /{etc,usr/lib}/systemd/network/80-container-host0.network
> > /etc/systemd/network/80-container-host0.network: symbolic link to
> > `/dev/null' /usr/lib/systemd/network/80-container-host0.network: ASCII text
> > $ cat /etc/systemd/network/eth.network
> > [Match]
> > Name=host0
> >
> > [Network]
> > Address=10.137.0.2/24
> > Gateway=10.137.0.1
> >
> > [DHCPv4]
> > UseDNS=false
> > -----
> >
> > However, this new .network file is never picked up by systemd-networkd (it
> > does provide a working network setup if the host0 interface is renamed).
> > Here is the debug output:
> >
> > -----
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: timestamp of
> > '/etc/systemd/network' changed
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: timestamp of
> > '/run/systemd/network' changed
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: Skipping overridden
> > file: /usr/lib/systemd/network/80-container-host0.network.
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: Configuration
> > file /etc/systemd/network/80-container-host0.network is marked
> > world-writable. Please remove world writability permission bits.
> > Proceeding anyway. Apr 04 21:29:00 lxc_archtest systemd-networkd[128]:
> > host0: found matching network
> > '/etc/systemd/network/80-container-host0.network' Apr 04 21:29:00
> > lxc_archtest systemd-networkd[128]: host0: requesting link status
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: bringing link up
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: link configured
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: link (with
> > ifindex 22) added
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: found matching
> > network '/etc/systemd/network/80-container-host0.network'
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: requesting link
> > status Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: bringing
> > link up Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: link
> > configured Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: link
> > (with ifindex 1) added
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: MAC address:
> > 36:9a:b1:98:ab:e1
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: link status
> > updated: 00000000 -> 0x00011043
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: link is up
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: host0: carrier on
> > Apr 04 21:29:00 lxc_archtest systemd-networkd[128]: Sent message
> > type=method_call sender=n/a destination=org.freedesktop.DBus
> > object=/org/freedesktop/DBus interface=org.freedesktop.DBus member=Hello
> > cookie=1 reply_cookie=0 error=n/a Apr 04 21:29:00 lxc_archtest
> > systemd-networkd[128]: Got message type=method_return
> > sender=org.freedesktop.DBus destination=:1.8 object=n/a interface=n/a
> > member=n/a cookie=1 reply_cookie=1 error=n/a Apr 04 21:29:00 lxc_archtest
> > systemd-networkd[128]: lo: link status updated: 00000000 -> 0x00010049 Apr
> > 04 21:29:00 lxc_archtest systemd-networkd[128]: lo: link is up Apr 04
> > 21:29:00 lxc_archtest systemd-networkd[128]: lo: carrier on Apr 04
> > 21:29:00 lxc_archtest systemd-networkd[128]: Got message type=signal
> > sender=org.freedesktop.DBus destination=:1.8 object=/org/freedesktop/DBus
> > interface=org.freedesktop.DBus member=NameAcquired cookie=2 reply_cookie=0
> > error=n/a Apr 04 21:29:02 lxc_archtest systemd-networkd[128]: Received
> > SIGINT. Apr 04 21:29:02 lxc_archtest systemd-networkd[128]: Assertion
> > 's->event->state != SD_EVENT_FINISHED' failed at
> > src/libsystemd/sd-event/sd-event.c:1308, function
> > sd_event_source_set_enabled(). Ignoring. Apr 04 21:29:02 lxc_archtest
> > systemd-networkd[128]: Assertion 's->event->state != SD_EVENT_FINISHED'
> > failed at src/libsystemd/sd-event/sd-event.c:1308, function
> > sd_event_source_set_enabled(). Ignoring. Apr 04 21:29:02 lxc_archtest
> > systemd-networkd[128]: Assertion 's->event->state != SD_EVENT_FINISHED'
> > failed at src/libsystemd/sd-event/sd-event.c:1308, function
> > sd_event_source_set_enabled(). Ignoring. -----
> >
> > I understand that the 1st matching configuration is applied but why does it
> > concern overriden files? Also, why does a symlink to /dev/null match all
> > interfaces (even loopback)?
> >
> > Thanks,
> > --
> > Leonid Isaev
> > GnuPG key fingerprint: C0DF 20D0 C075 C3F1 E1BE  775A A7AE F6CB 164B 5A6D
> >
> > _______________________________________________
> > systemd-devel mailing list
> > systemd-devel at lists.freedesktop.org
> > http://lists.freedesktop.org/mailman/listinfo/systemd-devel
> >

-- 
Leonid Isaev
GnuPG key fingerprint: C0DF 20D0 C075 C3F1 E1BE  775A A7AE F6CB 164B 5A6D
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