[Bug 1872118] Re: DHCP Cluster crashes after a few hours

Mon Aug 3 21:00:44 UTC 2020

Hello,

I am trying to setup a reproducer for the mentioned issue. I have 2
machines acting as peers with the following versions:

# lsb_release -a
No LSB modules are available.
Distributor ID:	Ubuntu
Description:	Ubuntu 20.04.1 LTS
Release:	20.04
Codename:	focal

# dpkg -l |grep -i isc-dh
ii  isc-dhcp-client                4.4.1-2.1ubuntu5                      amd64        DHCP client for automatically obtaining an IP address
ii  isc-dhcp-common                4.4.1-2.1ubuntu5                      amd64        common manpages relevant to all of the isc-dhcp packages
ii  isc-dhcp-server                4.4.1-2.1ubuntu5                      amd64        ISC DHCP server for automatic IP address assignment

=====

Primary configuration:  https://pastebin.ubuntu.com/p/XYj648MghK/
Secondary configuration: https://pastebin.ubuntu.com/p/PYkcshZCWK/

Started with:

# dhcpd -f -d -4 -cf /etc/dhcp/dhcpd.conf --no-pid ens4

---> Raised some DHCP requests to these servers.

balanced pool 560b8c263f40 12  total 221  free 111  backup 110  lts 0  max-misbal 33
Sending updates to failover-partner.
failover peer failover-partner: peer moves from recover-done to normal
failover peer failover-partner: Both servers normal
DHCPDISCOVER from 52:54:00:2d:53:93 via ens4
DHCPOFFER on 10.19.101.120 to 52:54:00:2d:53:93 (glistening-elephant) via ens4
DHCPREQUEST for 10.19.101.120 (10.19.101.236) from 52:54:00:2d:53:93 (glistening-elephant) via ens4
DHCPACK on 10.19.101.120 to 52:54:00:2d:53:93 (glistening-elephant) via ens4

DHCPREQUEST for 10.19.101.120 from 52:54:00:2d:53:93 (glistening-elephant) via ens4
DHCPACK on 10.19.101.120 to 52:54:00:2d:53:93 (glistening-elephant) via ens4
DHCPREQUEST for 10.19.101.121 from 52:54:00:53:a3:d8 (valiant-motmot) via ens4
DHCPACK on 10.19.101.121 to 52:54:00:53:a3:d8 (valiant-motmot) via ens4

---

failover peer failover-partner: Both servers normal
balancing pool 5606b2c95f10 12  total 221  free 221  backup 0  lts -110  max-own (+/-)22
balanced pool 5606b2c95f10 12  total 221  free 221  backup 0  lts -110  max-misbal 33
balancing pool 5606b2c95f10 12  total 221  free 111  backup 110  lts 0  max-own (+/-)22
balanced pool 5606b2c95f10 12  total 221  free 111  backup 110  lts 0  max-misbal 33
DHCPDISCOVER from 52:54:00:2d:53:93 via ens4: load balance to peer failover-partner
DHCPREQUEST for 10.19.101.120 (10.19.101.236) from 52:54:00:2d:53:93 via ens4: lease owned by peer

So far (after 1.5h) no crash has been reported in any of the servers. 

Questions:

1) Anything missed from the provided configuration?
2) Is this load or concurrency related? meaning a specific amount of leases needs to be allocated for this crash to happen? 

I will take a look to an existing crash/coredump.

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https://bugs.launchpad.net/bugs/1872118

Title:
  DHCP Cluster crashes after a few hours

Status in DHCP:
  New
Status in isc-dhcp package in Ubuntu:
  Confirmed

Bug description:

  I have a pair of DHCP serevrs running in a cluster on ubuntu 20.04, All worked perfectly until recently, when they started stopping with code=killed, status=6/ABRT.
  This is being fixed by 

  https://bugs.launchpad.net/bugs/1870729

  However now one stops after a few hours with the following errors. One
  can stay on line but not both.

  Syslog shows 
  Apr 10 17:20:15 dhcp-primary sh[6828]: ../../../../lib/isc/unix/socket.c:3361: INSIST(!sock->pending_send) failed, back trace
  Apr 10 17:20:15 dhcp-primary sh[6828]: #0 0x7fbe78702a4a in ??
  Apr 10 17:20:15 dhcp-primary sh[6828]: #1 0x7fbe78702980 in ??
  Apr 10 17:20:15 dhcp-primary sh[6828]: #2 0x7fbe7873e7e1 in ??
  Apr 10 17:20:15 dhcp-primary sh[6828]: #3 0x7fbe784e5609 in ??
  Apr 10 17:20:15 dhcp-primary sh[6828]: #4 0x7fbe78621103 in ??

  nothing in kern.log

  apport.log shows
  ERROR: apport (pid 6850) Fri Apr 10 17:20:15 2020: called for pid 6828, signal 6, core limit 0, dump mode 2
  ERROR: apport (pid 6850) Fri Apr 10 17:20:15 2020: not creating core for pid with dump mode of 2
  ERROR: apport (pid 6850) Fri Apr 10 17:20:15 2020: executable: /usr/sbin/dhcpd (command line "dhcpd -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf")
  ERROR: apport (pid 6850) Fri Apr 10 17:20:15 2020: is_closing_session(): no DBUS_SESSION_BUS_ADDRESS in environment
  ERROR: apport (pid 6850) Fri Apr 10 17:20:15 2020: wrote report /var/crash/_usr_sbin_dhcpd.0.crash

  /var/crash/_usr_sbin_dhcpd.0.crash shows

  ProblemType: Crash
  Architecture: amd64
  CrashCounter: 1
  Date: Fri Apr 10 17:20:15 2020
  DistroRelease: Ubuntu 20.04
  ExecutablePath: /usr/sbin/dhcpd
  ExecutableTimestamp: 1586210315
  ProcCmdline: dhcpd -user dhcpd -group dhcpd -f -4 -pf /run/dhcp-server/dhcpd.pid -cf /etc/dhcp/dhcpd.conf
  ProcEnviron: Error: [Errno 13] Permission denied: 'environ'
  ProcMaps: Error: [Errno 13] Permission denied: 'maps'
  ProcStatus:
   Name:  dhcpd
   Umask: 0022
   State: D (disk sleep)
   Tgid:  6828
   Ngid:  0
   Pid:   6828
   PPid:  1
   TracerPid:     0
   Uid:   113     113     113     113
   Gid:   118     118     118     118
   FDSize:        128
   Groups:
   NStgid:        6828
   NSpid: 6828
   NSpgid:        6828
   NSsid: 6828
   VmPeak:          236244 kB
   VmSize:          170764 kB
   VmLck:        0 kB
   VmPin:        0 kB
   VmHWM:    12064 kB
   VmRSS:    12064 kB
   RssAnon:           5940 kB
   RssFile:           6124 kB
   RssShmem:             0 kB
   VmData:           30792 kB
   VmStk:      132 kB
   VmExe:      592 kB
   VmLib:     5424 kB
   VmPTE:       76 kB
   VmSwap:               0 kB
   HugetlbPages:         0 kB
   CoreDumping:   1
   THP_enabled:   1
   Threads:       4
   SigQ:  0/7609
   SigPnd:        0000000000000000
   ShdPnd:        0000000000000000
   SigBlk:        0000000000000000
   SigIgn:        0000000000001000
   SigCgt:        0000000180000000
   CapInh:        0000000000000000
   CapPrm:        0000000000000000
   CapEff:        0000000000000000
   CapBnd:        0000003fffffffff
   CapAmb:        0000000000000000
   NoNewPrivs:    0
   Seccomp:       0
   Speculation_Store_Bypass:      thread vulnerable
   Cpus_allowed:  3
   Cpus_allowed_list:     0-1
   Mems_allowed:  00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,00000000,0000
  0000,00000000,00000000,00000001
   Mems_allowed_list:     0
   voluntary_ctxt_switches:       111
   nonvoluntary_ctxt_switches:    144
  Signal: 6
  Uname: Linux 5.4.0-21-generic x86_64
  UserGroups:

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