Bug#916689: systemd: login at console hangs after "Last login..." displayed, ssh hangs as well

[Raphael Manfredi]

Quoting Michael Biebl:
: What happens if you boot into emergency mode (add emergency to the
: kernel command line)?
: This will start a very minimal system without any networking or started
: services. Can you successfully login?
: 
: What happens if you boot into rescue mode (add rescue to the kernel
: command line)?
: This will boot into a minimal system with a few services like
: networking.service enabled.
: 
: What's the output of "ip a" in this case?

In emergency mode, no network, as expected:

	$ cat /root/ip.a-emergency
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 74:d0:2b:9d:5e:e4 brd ff:ff:ff:ff:ff:ff

In resue mode, NO NETWORK!

	$ cat /root/ip.a-rescue
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: eth0: <BROADCAST,MULTICAST> mtu 1500 qdisc noop state DOWN group default qlen 1000
    link/ether 74:d0:2b:9d:5e:e4 brd ff:ff:ff:ff:ff:ff

I understand this is not the expected situation, but how is systemd
configuring my network?  Who handles the /etc/network/interfaces file?

My /etc/default/networking file (as processed by /etc/init.d/networking
with sysvinit) is:

	$ cat /etc/default/networking
# Configuration for networking init script being run during
# the boot sequence

# Set to 'no' to skip interfaces configuration on boot
#CONFIGURE_INTERFACES=yes

# Don't configure these interfaces. Shell wildcards supported/
#EXCLUDE_INTERFACES=

# Set to 'yes' to enable additional verbosity
#VERBOSE=no

So, under systemd, how is network configuration in "rescue" mode
achieved?  If indeed my system is misconfigured, this could explain
the lockups with automount failing to access /usr/local.

And why, when booting is finished, is the network up correctly?

I see in "journactl -xb" output:

Dec 18 11:53:30 nice systemd[1]: Started Raise network interfaces.
-- Subject: Unit networking.service has finished start-up
-- Defined-By: systemd
-- Support: https://www.debian.org/support
-- 
-- Unit networking.service has finished starting up.
-- 
-- The start-up result is done.
Dec 18 11:53:30 nice systemd[1]: Reached target Network.
-- Subject: Unit network.target has finished start-up
-- Defined-By: systemd
-- Support: https://www.debian.org/support
-- 
-- Unit network.target has finished starting up.
-- 
-- The start-up result is done.

I did not check whilst in rescue mode what was the output of that,
unfortunately.  But the network "target" is properly configuring
the network here, this is what I understand.

Raphael