Comment 8 for bug 1551415

how do I debug this?

if i manually run 'ifup -a --read-environment' or 'systemctl start networking' it brings all stuff up cleanly.
by 'debug' i mean more than just looking at journalctl -u networking

below contents of network/interfaces, journalctl -u networking and contents of netwroking unit

---------

[Unit]
Description=Raise network interfaces
Documentation=man:interfaces(5)
DefaultDependencies=no
Wants=network.target
After=local-fs.target network-pre.target apparmor.service systemd-sysctl.service systemd-modules-load.service
Before=network.target shutdown.target network-online.target
Conflicts=shutdown.target

[Install]
WantedBy=multi-user.target
WantedBy=network-online.target

[Service]
Type=oneshot
EnvironmentFile=-/etc/default/networking
ExecStartPre=-/bin/sh -c '[ "$CONFIGURE_INTERFACES" != "no" ] && [ -n "$(ifquery --read-environment --list --exclude=lo)" ] && udevadm settle'
ExecStart=/sbin/ifup -a --read-environment
ExecStop=/sbin/ifdown -a --read-environment --exclude=lo
RemainAfterExit=true
TimeoutStartSec=3sec #modified from default which just made the machine hang on boot until timeout

------

# This file describes the network interfaces available on your system
# and how to activate them. For more information, see interfaces(5).

source /etc/network/interfaces.d/*

# The loopback network interface
auto lo
iface lo inet loopback

# The primary network interface
#allow-hotplug eno1
#allow-hotplug ipsec0
auto eno1
auto ipsec0

iface eno1 inet manual
        up ip link set eno1 up

iface ipsec0 inet static
        bridge_ports eno1
        address 192.168.15.113
        netmask 255.255.255.0
        gateway 192.168.15.254
        # dns-* options are implemented by the resolvconf package, if installed
        dns-nameservers 8.8.8.8
        #link-speed 1000
        #link-duplex full
        #ethernet-autoneg off
        #dns-search project.local
        #up dnsmasq -s lan -S //192.168.15.113 -u root --strict-order --pid-file=/run/dnsmasq-lan.pid --dhcp-no-override --except-interface=lo --interface=ipsec0 --dhcp-leasefile=/var/lib/dnsmasq.lan.leases --dhcp-authoritative --listen-address 192.168.15.113 --dhcp-range 192.168.15.101,192.168.15.199 --dhcp-lease-max=252 --bind-interfaces --dhcp-option-force=option:router,192.168.15.254 --dhcp-option-force=option:ntp-server,192.168.15.113
        up dnsmasq -s project -S //192.168.15.113 -u root --strict-order --pid-file=/run/dnsmasq-project.pid --dhcp-no-override --except-interface=lo --interface=ipsec0 --dhcp-leasefile=/var/lib/dnsmasq.project.leases --dhcp-authoritative --listen-address 192.168.15.113 --dhcp-range 192.168.15.101,192.168.15.199 --dhcp-lease-max=252 --bind-interfaces --dhcp-option-force=option:router,192.168.15.254 --dhcp-option-force=option:ntp-server,192.168.15.113
        down kill $(cat /run/dnsmasq-project.pid)

#allow-hotplug eno2
auto eno2
iface eno2 inet static
        address 192.168.100.100
        netmask 255.255.255.0
        #link-speed 100
        #link-duplex full
        #ethernet-autoneg off
        #gateway
        # dns-* options are implemented by the resolvconf package, if installed
        #dns-nameservers 10.10.200.10
        #dns-search project.local

-------------

-- Logs begin at Thu 2017-02-02 17:34:56 EET, end at Thu 2017-02-02 18:25:01 EET. --
Feb 02 17:35:13 linux systemd[1]: Starting Raise network interfaces...
Feb 02 17:35:13 linux ifup[6077]: /bin/run-parts --exit-on-error --verbose /etc/network/if-pre-up.d
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/bridge
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/ethtool
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/hostapd
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wireless-tools
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
Feb 02 17:35:13 linux ifup[6077]: Configuring interface lo=lo (inet)
Feb 02 17:35:13 linux ifup[6077]: /bin/run-parts --exit-on-error --verbose /etc/network/if-pre-up.d
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/bridge
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/ethtool
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/hostapd
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wireless-tools
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
Feb 02 17:35:13 linux ifup[6077]: /bin/ip link set dev lo up
Feb 02 17:35:13 linux ifup[6077]: /bin/run-parts --exit-on-error --verbose /etc/network/if-up.d
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/000resolvconf
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/arping
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/ethtool
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/ntpdate
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/openssh-server
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/upstart
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/wpasupplicant
Feb 02 17:35:13 linux ifup[6077]: /sbin/ifup: waiting for lock on /run/network/ifstate.eno1
Feb 02 17:35:13 linux ifup[6077]: Configuring interface ipsec0=ipsec0 (inet)
Feb 02 17:35:13 linux ifup[6077]: /bin/run-parts --exit-on-error --verbose /etc/network/if-pre-up.d
Feb 02 17:35:13 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/bridge
Feb 02 17:35:14 linux ifup[6077]: Waiting for ipsec0 to get ready (MAXWAIT is 32 seconds).
Feb 02 17:35:17 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/ethtool
Feb 02 17:35:17 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/hostapd
Feb 02 17:35:17 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wireless-tools
Feb 02 17:35:17 linux ifup[6077]: run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
Feb 02 17:35:17 linux ifup[6077]: /bin/ip addr add 192.168.15.113/255.255.255.0 broadcast 192.168.15.255 dev ipsec0 label ipsec0
Feb 02 17:35:17 linux ifup[6077]: /bin/ip link set dev ipsec0 up
Feb 02 17:35:17 linux ifup[6077]: /bin/ip route add default via 192.168.15.254 dev ipsec0 onlink
Feb 02 17:35:17 linux ifup[6077]: dnsmasq -s cdsl -S //192.168.15.113 -u root --strict-order --pid-file=/run/dnsmasq-cdsl.pid --dhcp-no-override --except-interface=lo --interface=ipsec0 --dhcp-leasefile=/var/lib/dnsmasq.cdsl.leases --dhcp-authoritative --listen-address 192.168.15.113 --dhcp-range 192.168.15.101,192.168.15.199 --dhcp-lease-max=252 --bind-interfaces --dhcp-option-force=option:router,192.168.15.254 --dhcp-option-force=option:ntp-server,192.168.15.113 &
Feb 02 17:35:17 linux ifup[6077]: /bin/run-parts --exit-on-error --verbose /etc/network/if-up.d
Feb 02 17:35:17 linux ifup[6077]: run-parts: executing /etc/network/if-up.d/000resolvconf
Feb 02 17:35:17 linux dnsmasq[6679]: started, version 2.75 cachesize 150
Feb 02 17:35:17 linux dnsmasq[6679]: compile time options: IPv6 GNU-getopt DBus i18n IDN DHCP DHCPv6 no-Lua TFTP conntrack ipset auth DNSSEC loop-detect inotify
Feb 02 17:35:17 linux dnsmasq-dhcp[6679]: DHCP, IP range 192.168.15.101 -- 192.168.15.199, lease time 1h
Feb 02 17:35:17 linux dnsmasq-dhcp[6679]: DHCP, sockets bound exclusively to interface ipsec0
Feb 02 17:35:17 linux dnsmasq[6679]: ignoring nameserver 192.168.15.113 - local interface
Feb 02 17:35:17 linux dnsmasq[6679]: reading /etc/resolv.conf
Feb 02 17:35:17 linux dnsmasq[6679]: using nameserver 127.0.0.1#53
Feb 02 17:35:17 linux dnsmasq[6679]: read /etc/hosts - 5 addresses
Feb 02 17:35:23 linux systemd[1]: networking.service: Start operation timed out. Terminating.
Feb 02 17:35:23 linux systemd[1]: Failed to start Raise network interfaces.
Feb 02 17:35:23 linux ifup[6077]: Terminated
Feb 02 17:35:23 linux dnsmasq[6679]: exiting on receipt of SIGTERM
Feb 02 17:35:23 linux systemd[1]: networking.service: Unit entered failed state.
Feb 02 17:35:23 linux systemd[1]: networking.service: Failed with result 'timeout'.

then it is started immediately from rc.local: "systemctl start networking"

Feb 02 17:35:24 linux systemd[1]: Starting Raise network interfaces...
Feb 02 17:35:24 linux ifup[6916]: /bin/run-parts --exit-on-error --verbose /etc/network/if-pre-up.d
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-pre-up.d/bridge
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-pre-up.d/ethtool
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-pre-up.d/hostapd
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-pre-up.d/wireless-tools
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-pre-up.d/wpasupplicant
Feb 02 17:35:24 linux ifup[6916]: /bin/run-parts --exit-on-error --verbose /etc/network/if-up.d
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/000resolvconf
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/arping
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/ethtool
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/ntpdate
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/openssh-server
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/upstart
Feb 02 17:35:24 linux ifup[6916]: run-parts: executing /etc/network/if-up.d/wpasupplicant
Feb 02 17:35:24 linux systemd[1]: Started Raise network interfaces.