在我发现这个问题之前，我也在answers.launchpad.net网站上发布过这个问题，很抱歉重复了...
我刚刚将运行故障转移的两个 DHCP 服务器都升级到 Xenial，现在它们都不允许 isc-dhcp-server 启动。
我已经搜寻了一上午，甚至 30 多秒都不知道该跑到哪里去。
Mar 16 11:04:48 cooper dhcpd[18118]: failover peer dhcp: I move from startup to recover
Mar 16 11:04:49 cooper sh[18118]: ../../../../lib/isc/unix/socket.c:3295: INSIST(!sock->pending_send) failed, back trace
Mar 16 11:04:49 cooper sh[18118]: #0 0x7f9913bf1537 in ??
Mar 16 11:04:49 cooper sh[18118]: #1 0x7f9913bf148a in ??
Mar 16 11:04:49 cooper sh[18118]: #2 0x7f9913c27d62 in ??
Mar 16 11:04:49 cooper sh[18118]: #3 0x7f991360166a in ??
Mar 16 11:04:49 cooper sh[18118]: #4 0x7f991391f01d in ??
Mar 16 11:04:49 cooper systemd[1]: isc-dhcp-server.service: Main process exited, code=killed, status=6/ABRT
Mar 16 11:04:49 cooper systemd[1]: isc-dhcp-server.service: Unit entered failed state.
Mar 16 11:04:49 cooper systemd[1]: isc-dhcp-server.service: Failed with result 'signal'.
它似乎可以运行，但在崩溃前大约 30 秒内无法提供 IP。任何帮助都值得感激。
更多信息：
ii isc-dhcp-client 4.3.3-5ubuntu9 amd64 DHCP client for automatically obtaining an IP address
ii isc-dhcp-common 4.3.3-5ubuntu9 amd64 common files used by all of the isc-dhcp packages
ii isc-dhcp-server 4.3.3-5ubuntu9 amd64 ISC DHCP server for automatic IP address assignment
brad@cooper:/run$ sudo /usr/sbin/dhcpd -d -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf
Internet Systems Consortium DHCP Server 4.3.3
Copyright 2004-2015 Internet Systems Consortium.
All rights reserved.
For info, please visit https://www.isc.org/software/dhcp/
Config file: /etc/dhcp/dhcpd.conf
Database file: /var/lib/dhcp/dhcpd.leases
PID file: /run/dhcp-server/dhcpd.pid
Wrote 0 deleted host decls to leases file.
Wrote 0 new dynamic host decls to leases file.
Wrote 0 leases to leases file.
Listening on LPF/eth0/00:50:56:bb:6b:db/192.168.1.0/24
Sending on LPF/eth0/00:50:56:bb:6b:db/192.168.1.0/24
Sending on Socket/fallback/fallback-net
failover peer dhcp: I move from recover to startup
Server starting service.
../../../../lib/isc/unix/socket.c:996: epoll_ctl(DEL), 11: Bad file descriptor
../../../../lib/isc/unix/socket.c:996: epoll_ctl(DEL), 11: Bad file descriptor
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via eth0: not responding (startup)
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via 192.168.1.2: not responding (startup)
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via 192.168.1.3: not responding (startup)
DHCPDISCOVER from 64:52:99:01:74:07 via eth0: not responding (startup)
DHCPDISCOVER from 64:52:99:01:74:07 via 192.168.1.3: not responding (startup)
DHCPDISCOVER from 64:52:99:01:74:07 via 192.168.1.2: not responding (startup)
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via eth0: not responding (startup)
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via 192.168.1.3: not responding (startup)
DHCPDISCOVER from 7c:69:f6:e1:e2:b7 via 192.168.1.2: not responding (startup)
DHCPDISCOVER from 00:11:d9:61:c2:43 via eth0: not responding (startup)
DHCPDISCOVER from 00:11:d9:61:c2:43 via 192.168.1.3: not responding (startup)
DHCPDISCOVER from 00:11:d9:61:c2:43 via 192.168.1.2: not responding (startup)
../../../../lib/isc/unix/socket.c:3295: INSIST(!sock->pending_send) failed, back trace
#0 0x7fbdfcd7b537 in ??
#1 0x7fbdfcd7b48a in ??
#2 0x7fbdfcdb1d62 in ??
#3 0x7fbdfc78b66a in ??
#4 0x7fbdfcaa901d in ??