apport information

** Attachment added: "ProcCpuinfo.txt"

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  IPVS incorrectly reverse-NATs traffic to LVS host

Status in linux package in Ubuntu:

Bug description:
  We have observed the following behaviour on our LVS systems, which is
  causing issues with our monitor scripts.  The systems are running
  Ubuntu 14.04.5 LTS and I've tested both with the stock 3.13.0 kernel
  (-100 and -116) and the 4.4.0-72 xenial kernel.

  Our systems are set up in direct routing mode for the services they
  handle.  Our monitor scripts for DNS send test queries to our DNS
  servers using their real IPs.  Sporadically, we have seen these checks
  fail as the DNS answers are coming back from the wrong IP address.

  We debugged this using tcpdump, and found that the response packets
  coming into the LVS systems were using the correct IPs (i.e. the real
  IPs on the DNS servers).  However, applications see the responses as
  coming from a VIP instead.

  All of this has been established using UDP traffic.

  I have tracked this behaviour down to a specific case, which I can only 
assume is associated with how the kernel handles LVS NAT connections (i.e. 
masquerade mode):
  - If a DNS query is made on the LVS server to a DNS VIP, that creates an 
entry in the connection table, and is keyed on (srcip:sport -> dstip:dport) and 
associated with (vip:vport) - for example, (lvsip:50000 -> dnsip:53) associated 
with (dnsvip:53)
  - If a subsequent DNS query is made from the same UDP port, the response is 
correct as seen by tcpdump
  - When the response is seen by the application, the source IP address for the 
response is wrong

  I have inferred that as the response comes back from dnsip:53 and
  there is a connection table entry, IPVS seems to assume NAT is in use,
  and translates it using the entry (lvsip:50000 -> dnsip:53).  The
  application layer then sees the response from (dnsvip:53), which is

  /proc/version_signature (from both nodes):
    Ubuntu 3.13.0-100.147-generic 3.13.11-ckt39
    Ubuntu 4.4.0-72.93~14.04.1-generic 4.4.49

  IPVS Configuration:

  root@lvs5:~# ipvsadm -Sn
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -t -s rr
  -a -t -r -g -w 10
  -A -t -s rr
  -a -t -r -g -w 10
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -t -s wlc
  -a -t -r -g -w 10
  -a -t -r -g -w 10
  -A -u -s rr
  -a -u -r -g -w 10
  -A -u -s rr
  -a -u -r -g -w 10
   total 0
   crw-rw---- 1 root audio 116,  1 Apr 11 13:18 seq
   crw-rw---- 1 root audio 116, 33 Apr 11 13:18 timer
  AplayDevices: Error: [Errno 2] No such file or directory
  ApportVersion: 2.14.1-0ubuntu3.23
  Architecture: amd64
  ArecordDevices: Error: [Errno 2] No such file or directory
  AudioDevicesInUse: Error: command ['fuser', '-v', '/dev/snd/seq', 
'/dev/snd/timer'] failed with exit code 1:
  CRDA: Error: [Errno 2] No such file or directory
  DistroRelease: Ubuntu 14.04
  HibernationDevice: RESUME=/dev/mapper/lvs5--vg-swap
  IwConfig: Error: [Errno 2] No such file or directory
   Bus 002 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
   Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
   Bus 001 Device 003: ID 413c:a001 Dell Computer Corp. Hub
   Bus 001 Device 002: ID 8087:0024 Intel Corp. Integrated Rate Matching Hub
   Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub
  MachineType: Dell Inc. PowerEdge R320
  Package: linux (not installed)
  ProcFB: 0 VESA VGA
  ProcKernelCmdLine: BOOT_IMAGE=/vmlinuz-4.4.0-72-generic 
root=/dev/mapper/hostname--vg-root ro quiet splash vt.handoff=7
  ProcVersionSignature: Ubuntu 4.4.0-72.93~14.04.1-generic 4.4.49
   linux-restricted-modules-4.4.0-72-generic N/A
   linux-backports-modules-4.4.0-72-generic  N/A
   linux-firmware                            1.127.23
  RfKill: Error: [Errno 2] No such file or directory
  Tags:  trusty
  Uname: Linux 4.4.0-72-generic x86_64
  UpgradeStatus: No upgrade log present (probably fresh install)
  UserGroups: btcats daemon dba named oinstall yimsora
  _MarkForUpload: True 01/29/2015
  dmi.bios.vendor: Dell Inc.
  dmi.bios.version: 2.4.2 0KM5PX
  dmi.board.vendor: Dell Inc.
  dmi.board.version: A02
  dmi.chassis.type: 23
  dmi.chassis.vendor: Dell Inc.
dmi:bvnDellInc.:bvr2.4.2:bd01/29/2015:svnDellInc.:pnPowerEdgeR320:pvr:rvnDellInc.:rn0KM5PX:rvrA02:cvnDellInc.:ct23:cvr: PowerEdge R320
  dmi.sys.vendor: Dell Inc.

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