Created by setting VERBOSE="yes" and DEBUG="yes" in /etc/default/networking

ifupdown2_debug_log

root@frr7-test:/var/log/frr# !journalctl
journalctl -xeu networking.service --no-pager
-- Logs begin at Mon 2019-05-06 17:19:18 UTC, end at Mon 2019-05-06 17:22:53 UTC. --
May 06 17:19:18 frr7-test systemd[1]: Starting ifupdown2 networking initialization...
-- Subject: Unit networking.service has begun start-up
-- Defined-By: systemd
-- Support: https://www.debian.org/support
-- 
-- Unit networking.service has begun starting up.
May 06 17:19:18 frr7-test networking[559]: networking: Configuring network interfaces
May 06 17:19:19 frr7-test networking[559]: debug: args = Namespace(CLASS=None, all=True, debug=True, excludepats=None, force=False, iflist=[], interfacesfile=None, interfacesfileformat='native', noact=False, noaddons=False, nocache=False, perfmode=True, printdependency=None, quiet=False, skipupperifaces=False, syntaxcheck=False, syslog=False, type=None, verbose=True, withdepends=False)
May 06 17:19:19 frr7-test networking[559]: debug: creating ifupdown object ..
May 06 17:19:19 frr7-test networking[559]: debug: {'ifreload_down_changed': '0', 'multiple_vlan_aware_bridge_support': '0', 'ifaceobj_squash': '0', 'no_repeats': {'bridge-vlan-aware': 'yes'}, 'ifquery_check_error_str': 'fail', 'delay_admin_state_change': '0', 'addon_syntax_check': '0', 'ifquery_check_unknown_str': '', 'addr_config_squash': '0', 'adjust_logical_dev_mtu': '1', 'default_interfaces_configfile': '/etc/network/interfaces', 'template_lookuppath': '/etc/network/ifupdown2/templates', 'link_master_slave': '1', 'template_enable': '1', 'ifquery_ifacename_expand_range': '0', 'template_engine': 'mako', 'addon_scripts_support': '1', 'ifquery_check_success_str': 'pass', 'addon_python_modules_support': '1', 'disable_cli_interfacesfile': '0'}
May 06 17:19:19 frr7-test networking[559]: info: loading builtin modules from /usr/share/ifupdown2/addons
May 06 17:19:19 frr7-test networking[559]: debug: vlan: using reserved vlan range (0, 0)
May 06 17:19:19 frr7-test networking[559]: debug: bridge: using reserved vlan range (0, 0)
May 06 17:19:19 frr7-test networking[559]: info: executing /bin/pidof mstpd
May 06 17:19:19 frr7-test networking[559]: info: executing /sbin/ip rule show
May 06 17:19:19 frr7-test networking[559]: info: executing /sbin/ip -6 rule show
May 06 17:19:19 frr7-test networking[559]: info: module ethtool not loaded (module init failed: no /sbin/ethtool found)
May 06 17:19:19 frr7-test networking[559]: info: module ethtool not loaded (module init failed: no /sbin/ethtool found)
May 06 17:19:19 frr7-test networking[559]: info: looking for user scripts under /etc/network
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-pre-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-post-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-pre-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-post-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: 'link_master_slave' is set. slave admin state changes will be delayed till the masters admin state change.
May 06 17:19:19 frr7-test networking[559]: info: processing interfaces file /etc/network/interfaces
May 06 17:19:19 frr7-test networking[559]: debug: processing sourced line ..'source /etc/network/interfaces.d/*'
May 06 17:19:19 frr7-test networking[559]: debug: populate_dependency_info: deleting blacklisted interface ens18
May 06 17:19:19 frr7-test networking[559]: debug: scheduling '['pre-up', 'up', 'post-up']' for ['lo']
May 06 17:19:19 frr7-test networking[559]: debug: dependency graph {
May 06 17:19:19 frr7-test networking[559]:         lo : []
May 06 17:19:19 frr7-test networking[559]: }
May 06 17:19:19 frr7-test networking[559]: debug: graph roots (interfaces that dont have dependents): ['lo']
May 06 17:19:19 frr7-test networking[559]: info: lo: running ops ...
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module link
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module tunnel
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module bond
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module batman_adv
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module vlan
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module vxlan
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module bridge
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module bridgevlan
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module mstpctl
May 06 17:19:19 frr7-test networking[559]: debug: lo: pre-up : running module vrf
May 06 17:19:19 frr7-test networking[559]: info: executing ip -o -d link show dev lo
May 06 17:19:19 frr7-test networking[559]: debug: _cache_get(['lo', 'master']) : ['master']
May 06 17:19:19 frr7-test networking[559]: info: lo: netlink: ip link set dev lo up
May 06 17:19:19 frr7-test networking[559]: debug: TXed  RTM_NEWLINK, pid 601, seq 1, 40 bytes
May 06 17:19:19 frr7-test networking[559]: debug: RXed  NLMSG_ERROR, pid 601, seq 1, 36 bytes code NLE_SUCCESS...this is an ACK
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running module dhcp
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running module address
May 06 17:19:19 frr7-test networking[559]: info: executing ip -force -batch - [addr add 10.66.66.10/32 dev lo
May 06 17:19:19 frr7-test networking[559]: ]
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running module addressvirtual
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running script /etc/network/if-up.d/openssh-server
May 06 17:19:19 frr7-test networking[559]: info: executing /etc/network/if-up.d/openssh-server
May 06 17:19:19 frr7-test networking[559]: debug: lo: up : running script /etc/network/if-up.d/upstart
May 06 17:19:19 frr7-test networking[559]: info: executing /etc/network/if-up.d/upstart
May 06 17:19:19 frr7-test networking[559]: debug: lo: post-up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: lo: statemanager sync state pre-up
May 06 17:19:19 frr7-test networking[559]: debug: saving state ..
May 06 17:19:19 frr7-test networking[559]: debug: args = Namespace(CLASS=None, all=False, debug=True, excludepats=None, force=False, iflist=['ens18'], interfacesfile=None, interfacesfileformat='native', noact=False, noaddons=False, nocache=False, perfmode=False, printdependency=None, quiet=False, skipupperifaces=False, syntaxcheck=False, syslog=False, type=None, verbose=True, withdepends=False)
May 06 17:19:19 frr7-test networking[559]: debug: creating ifupdown object ..
May 06 17:19:19 frr7-test networking[559]: debug: {'ifreload_down_changed': '0', 'multiple_vlan_aware_bridge_support': '0', 'ifaceobj_squash': '0', 'no_repeats': {'bridge-vlan-aware': 'yes'}, 'ifquery_check_error_str': 'fail', 'delay_admin_state_change': '0', 'addon_syntax_check': '0', 'ifquery_check_unknown_str': '', 'addr_config_squash': '0', 'adjust_logical_dev_mtu': '1', 'default_interfaces_configfile': '/etc/network/interfaces', 'template_lookuppath': '/etc/network/ifupdown2/templates', 'link_master_slave': '0', 'template_enable': '1', 'ifquery_ifacename_expand_range': '0', 'template_engine': 'mako', 'addon_scripts_support': '1', 'ifquery_check_success_str': 'pass', 'addon_python_modules_support': '1', 'disable_cli_interfacesfile': '0'}
May 06 17:19:19 frr7-test networking[559]: info: loading builtin modules from /usr/share/ifupdown2/addons
May 06 17:19:19 frr7-test networking[559]: debug: vlan: using reserved vlan range (0, 0)
May 06 17:19:19 frr7-test networking[559]: debug: bridge: using reserved vlan range (0, 0)
May 06 17:19:19 frr7-test networking[559]: info: executing /bin/pidof mstpd
May 06 17:19:19 frr7-test networking[559]: info: executing /sbin/ip rule show
May 06 17:19:19 frr7-test networking[559]: info: executing /sbin/ip -6 rule show
May 06 17:19:19 frr7-test networking[559]: info: module ethtool not loaded (module init failed: no /sbin/ethtool found)
May 06 17:19:19 frr7-test networking[559]: info: module ethtool not loaded (module init failed: no /sbin/ethtool found)
May 06 17:19:19 frr7-test networking[559]: info: looking for user scripts under /etc/network
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-pre-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-post-up.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-pre-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: loading scripts under /etc/network/if-post-down.d ...
May 06 17:19:19 frr7-test networking[559]: info: processing interfaces file /etc/network/interfaces
May 06 17:19:19 frr7-test networking[559]: debug: processing sourced line ..'source /etc/network/interfaces.d/*'
May 06 17:19:19 frr7-test networking[559]: debug: scheduling '['pre-up', 'up', 'post-up']' for ['ens18']
May 06 17:19:19 frr7-test networking[559]: debug: dependency graph {
May 06 17:19:19 frr7-test networking[559]:         lo : []
May 06 17:19:19 frr7-test networking[559]:         ens18 : []
May 06 17:19:19 frr7-test networking[559]: }
May 06 17:19:19 frr7-test networking[559]: info: ens18: running ops ...
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module link
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module tunnel
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module bond
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module batman_adv
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module vlan
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module vxlan
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module bridge
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module bridgevlan
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module mstpctl
May 06 17:19:19 frr7-test networking[559]: debug: ens18: pre-up : running module vrf
May 06 17:19:19 frr7-test networking[559]: info: executing ip -o -d link show dev ens18
May 06 17:19:19 frr7-test networking[559]: debug: _cache_get(['ens18', 'master']) : ['master']
May 06 17:19:19 frr7-test networking[559]: info: ens18: netlink: ip link set dev ens18 up
May 06 17:19:19 frr7-test networking[559]: debug: TXed  RTM_NEWLINK, pid 625, seq 1, 44 bytes
May 06 17:19:19 frr7-test networking[559]: debug: RXed  NLMSG_ERROR, pid 625, seq 1, 36 bytes code NLE_SUCCESS...this is an ACK
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running module dhcp
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running module address
May 06 17:19:19 frr7-test networking[559]: info: executing ip -o addr show dev ens18
May 06 17:19:19 frr7-test networking[559]: info: executing ip -force -batch - [addr add 10.66.20.125/29 dev ens18
May 06 17:19:19 frr7-test networking[559]: ]
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running module addressvirtual
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running script /etc/network/if-up.d/openssh-server
May 06 17:19:19 frr7-test networking[559]: info: executing /etc/network/if-up.d/openssh-server
May 06 17:19:19 frr7-test networking[559]: debug: ens18: up : running script /etc/network/if-up.d/upstart
May 06 17:19:19 frr7-test networking[559]: info: executing /etc/network/if-up.d/upstart
May 06 17:19:19 frr7-test networking[559]: debug: ens18: post-up : running module usercmds
May 06 17:19:19 frr7-test networking[559]: debug: ens18: statemanager sync state pre-up
May 06 17:19:19 frr7-test networking[559]: debug: saving state ..
May 06 17:19:19 frr7-test systemd[1]: Started ifupdown2 networking initialization.
-- 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.