Created attachment 1087945 [details]
Working patch

Tested and working patch.

Setup an IPv6 address resource that collides with one on the network:
# pcs resource create IPv6 IPaddr2 ip=XXXX::10

Before:
# rpm -q resource-agents
resource-agents-3.9.5-54.el7_2.6.x86_64
# pcs resource enable IPv6
# tail -f /var/log/pacemaker.log
...
IPaddr2(IPv6)[5109]:    2016/03/01_13:02:28 WARNING: XXXX::10 still has 'tentative' status. (ignored)

After:
# rpm -q resource-agents
resource-agents-3.9.5-63.el7.x86_64
# pcs resource enable IPv6
# tail -f /var/log/pacemaker.log
...
IPaddr2(IPv6)[7572]:	2016/03/01_13:08:24 ERROR: IPv6 address collision XXXX::10 [DAD]

I have verified that DAD is used for ipv6 address collision detection in
resource-agents-3.9.5-73.el6.x86_64

-----

setup:

Have active ipv6 address and stopped cluster resource with the same address.

[root@virt-140 ~]# ping6 -c 2 2620:52:0:2246:1800:ff:fe00:8c
PING 2620:52:0:2246:1800:ff:fe00:8c(2620:52:0:2246:1800:ff:fe00:8c) 56 data bytes
64 bytes from 2620:52:0:2246:1800:ff:fe00:8c: icmp_seq=1 ttl=64 time=0.057 ms
64 bytes from 2620:52:0:2246:1800:ff:fe00:8c: icmp_seq=2 ttl=64 time=0.064 ms

--- 2620:52:0:2246:1800:ff:fe00:8c ping statistics ---
2 packets transmitted, 2 received, 0% packet loss, time 1000ms
rtt min/avg/max/mdev = 0.057/0.060/0.064/0.008 ms

[root@virt-140 ~]# pcs resource show ClusterIP
 Resource: ClusterIP (class=ocf provider=heartbeat type=IPaddr2)
  Attributes: ip=2620:52:0:2246:1800:ff:fe00:8c cidr_netmask=64 
  Meta Attrs: target-role=Stopped 
  Operations: start interval=0s timeout=20s (ClusterIP-start-interval-0s)
              stop interval=0s timeout=20s (ClusterIP-stop-interval-0s)
              monitor interval=10s timeout=20s (ClusterIP-monitor-interval-10s)

[root@virt-140 ~]# pcs status
Cluster name: STSRHTS24626
Last updated: Wed Jul 27 11:32:59 2016          Last change: Wed Jul 27 11:28:54 2016 by root via crm_resource on virt-140
Stack: corosync
Current DC: virt-149 (version 1.1.13-10.el7-44eb2dd) - partition with quorum
4 nodes and 13 resources configured

Online: [ virt-140 virt-148 virt-149 virt-150 ]

Full list of resources:

 fence-virt-140 (stonith:fence_xvm):    Started virt-140
 fence-virt-148 (stonith:fence_xvm):    Started virt-148
 fence-virt-149 (stonith:fence_xvm):    Started virt-149
 fence-virt-150 (stonith:fence_xvm):    Started virt-150
 Clone Set: dlm-clone [dlm]
     Started: [ virt-140 virt-148 virt-149 virt-150 ]
 Clone Set: clvmd-clone [clvmd]
     Started: [ virt-140 virt-148 virt-149 virt-150 ]
 ClusterIP      (ocf::heartbeat:IPaddr2):       (target-role:Stopped) Stopped

PCSD Status:
  virt-140: Online
  virt-148: Online
  virt-149: Online
  virt-150: Online

Daemon Status:
  corosync: active/disabled
  pacemaker: active/disabled
  pcsd: active/enabled

before the fix (resource-agents-3.9.5-54.el7.x86_64)
====================================================

# pcs resource enable ClusterIP
# pcs status | grep ClusterIP
 ClusterIP      (ocf::heartbeat:IPaddr2):       Stopped

# tail /var/log/messages
...
Jul 30 11:39:07 virt-140 IPaddr2(ClusterIP)[4523]: INFO: Adding inet6 address 2620:52:0:2246:1800:ff:fe00:8c/64 to device eth0
Jul 30 11:39:07 virt-140 IPaddr2(ClusterIP)[4523]: INFO: Bringing device eth0 up
>>> Jul 30 11:39:11 virt-140 IPaddr2(ClusterIP)[4523]: WARNING: 2620:52:0:2246:1800:ff:fe00:90 still has 'tentative' status. (ignored)
Jul 30 11:39:11 virt-140 IPaddr2(ClusterIP)[4523]: INFO: /usr/libexec/heartbeat/send_ua -i 200 -c 5 2620:52:0:2246:1800:ff:fe00:8c 64 eth0


after the fix (resource-agents-3.9.5-73.el7.x86_64)
===================================================

# pcs resource enable ClusterIP
# pcs status | grep ClusterIP
 ClusterIP      (ocf::heartbeat:IPaddr2):       Stopped

# tail /var/log/messages
...
Jul 27 11:36:41 virt-150 IPaddr2(ClusterIP)[18826]: INFO: Adding inet6 address 2620:52:0:2246:1800:ff:fe00:8c/64 to device eth0
Jul 27 11:36:41 virt-150 IPaddr2(ClusterIP)[18826]: INFO: Bringing device eth0 up
Jul 27 11:36:41 virt-150 kernel: IPv6: eth0: IPv6 duplicate address 2620:52:0:2246:1800:ff:fe00:8c detected!
>>> Jul 27 11:36:42 virt-150 IPaddr2(ClusterIP)[18826]: ERROR: IPv6 address collision 2620:52:0:2246:1800:ff:fe00:8c [DAD]
Jul 27 11:36:42 virt-150 IPaddr2(ClusterIP)[18826]: ERROR: run_send_ua failed.
Jul 27 11:36:42 virt-150 lrmd[24755]:  notice: ClusterIP_start_0:18826:stderr [ ocf-exit-reason:run_send_ua failed. ]
Jul 27 11:36:42 virt-150 crmd[24758]:  notice: Operation ClusterIP_start_0: unknown error (node=virt-150, call=74, rc=1, cib-update=58, confirmed=true)
Jul 27 11:36:42 virt-150 crmd[24758]:  notice: virt-150-ClusterIP_start_0:74 [ ocf-exit-reason:run_send_ua failed.\n ]
Jul 27 11:36:42 virt-150 IPaddr2(ClusterIP)[18911]: INFO: IP status = no, IP_CIP=
Jul 27 11:36:42 virt-150 crmd[24758]:  notice: Operation ClusterIP_stop_0: ok (node=virt-150, call=75, rc=0, cib-update=59, confirmed=true)

Since the problem described in this bug report should be
resolved in a recent advisory, it has been closed with a
resolution of ERRATA.

For information on the advisory, and where to find the updated
files, follow the link below.

If the solution does not work for you, open a new bug report.

https://rhn.redhat.com/errata/RHBA-2016-2174.html