I am experiencing this same issue after upgrading from jessie to stretch However these statements:
"Jul 27 20:18:21 hedwig isc-dhcp-server[17921]: Starting ISC DHCPv4 server: dhcpddhcpd service already running (pid file /var/run/dhcpd.pid currenty exists) ... failed!" Especially: "Hence, it seems the upgrade process leaves a dangling PID file around. Removing that PID file manually solved the problem for me." Is not quite true for me. It it fails to start isc-dhcpd leave a dangling file which must be removed manually before starting / restarting isc-dhcpd. it is 2019 does isc-dhcp server leave gangling /var/run/dhcpd.pid files on failure to start? The answer to this non rhetorical question... well yes... for me it does. again... and again... and again. -------------------------------- -- Unit isc-dhcp-server.service has begun starting up. Mar 22 17:31:15 dungeon isc-dhcp-server[13036]: DHCPv4 interfaces are no longer set by the INTERFACES variable in Mar 22 17:31:15 dungeon isc-dhcp-server[13036]: /etc/default/isc-dhcp-server. Please use INTERFACESv4 instead. Mar 22 17:31:15 dungeon isc-dhcp-server[13036]: Migrating automatically for now, but this will go away in the future. Mar 22 17:31:15 dungeon isc-dhcp-server[13036]: Launching IPv4 server only. Mar 22 17:31:15 dungeon isc-dhcp-server[13036]: Starting ISC DHCPv4 server: dhcpddhcpd service already running (pid file /var/run/dhcpd.pid currenty exists) ... failed! Mar 22 17:31:15 dungeon systemd[1]: isc-dhcp-server.service: Control process exited, code=exited status=1 Mar 22 17:31:15 dungeon systemd[1]: Failed to start LSB: DHCP server. -- Subject: Unit isc-dhcp-server.service has failed -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit isc-dhcp-server.service has failed. -- -- The result is failed. Mar 22 17:31:15 dungeon systemd[1]: isc-dhcp-server.service: Unit entered failed state. Mar 22 17:31:15 dungeon systemd[1]: isc-dhcp-server.service: Failed with result 'exit-code'. Mar 22 17:33:02 dungeon systemd[1]: Starting LSB: DHCP server... -- Subject: Unit isc-dhcp-server.service has begun start-up -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit isc-dhcp-server.service has begun starting up. Mar 22 17:33:02 dungeon isc-dhcp-server[13078]: Launching IPv4 server only. Mar 22 17:33:02 dungeon isc-dhcp-server[13078]: Starting ISC DHCPv4 server: dhcpddhcpd service already running (pid file /var/run/dhcpd.pid currenty exists) ... failed! Mar 22 17:33:02 dungeon systemd[1]: isc-dhcp-server.service: Control process exited, code=exited status=1 Mar 22 17:33:02 dungeon systemd[1]: Failed to start LSB: DHCP server. -- Subject: Unit isc-dhcp-server.service has failed -- Defined-By: systemd -- Support: https://www.debian.org/support -- -- Unit isc-dhcp-server.service has failed. -- -- The result is failed. Mar 22 17:33:02 dungeon systemd[1]: isc-dhcp-server.service: Unit entered failed state. Mar 22 17:33:02 dungeon systemd[1]: isc-dhcp-server.service: Failed with result 'exit-code'. root@dungeon:/home/bit# root@dungeon:/home/bit# rm /var/run/dhcpd.pid root@dungeon:/home/bit# /etc/init.d/isc-dhcp-server restart [ ok ] Restarting isc-dhcp-server (via systemctl): isc-dhcp-server.service. Above is not first time... I experienced this at least up to three (3) times while configuring.
