HA: OpenStack cluster became non-functional when management interface of active controller has incorrect configuration

[Timur Nurlygayanov]

Steps To Reproduce:
1. Deploy OpenStack cloud in HA mode using Fuel 5.0.1 or Fuel 5.1 test ISO (CentOS, 3 controllers + mongo, 2 computes, Nova Network with DHCP, Install Ceilometer and Sahara).
2. Run OSTF tests and verify that all works fine.
3. Login to active controller and re-configure management interface IP address, for example:

eth0.101 Link encap:Ethernet HWaddr 64:C5:1E:B8:2A:0A
          inet addr:192.168.0.2 Bcast:192.168.0.255 Mask:255.255.255.0
          inet6 addr: fe80::66c5:1eff:feb8:2a0a/64 Scope:Link

eth0.101-hapr Link encap:Ethernet HWaddr CE:5E:96:0F:B7:2D
          inet addr:192.168.0.2 Bcast:0.0.0.0 Mask:255.255.255.0
          inet6 addr: fe80::cc5e:96ff:fe0f:b72d/64 Scope:Link
____________________
and run the following command to change IP address:
ifconfig eth0.101 192.168.0.100

4. Start OSTF tests again.

Observed Result:
All OSTF tests will fail, because HA cluster attempts to connect to the first controller via management interface. The failover scenario doesn't work for this case.