Comment 0 for bug 1791818

Brief Description
-----------------
Boot up VMs on a single node system, make sure VMs are pingable. After host reboot host, VMs are in Active state, but some of VMs are not pingable.

Severity
--------
Major

Steps to Reproduce
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1. boot up 5VMs, ping 5 VMs
2. reboot -f host
3. check VMs in Active state
4. ping VMs

Expected Behavior
------------------
All pings success

Actual Behavior
----------------
some VM(s) failed to ping

Reproducibility
---------------
Reproducible (about 4/10 reproducibility)

System Configuration
--------------------
One node system

Branch/Pull Time/Commit
-----------------------
master as of 2018-09-09_20-18-00

Timestamp/Logs
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[2018-09-10 06:05:46,435] 264 DEBUG MainThread ssh.send :: Send 'nova --os-username 'admin' --os-password 'Li69nux*' --os-project-name admin --os-auth-url http://127.168.204.2:5000/v3 --os-user-domain-name Default --os-project-domain-name Default --os-region-name RegionOne list --all-tenants'
[2018-09-10 06:05:50,108] 391 DEBUG MainThread ssh.expect :: Output:
+--------------------------------------+--------------------------------+----------------------------------+--------+------------+-------------+------------------------------------------------------------+
| ID | Name | Tenant ID | Status | Task State | Power State | Networks |
+--------------------------------------+--------------------------------+----------------------------------+--------+------------+-------------+------------------------------------------------------------+
| 7379e11d-a9b6-49f7-9b52-3324c8d7d28b | tenant2-image_ephemswap-6 | b4fec267b80a4375a92493443afbaa56 | ACTIVE | - | Running | tenant2-net1=172.18.1.135; tenant2-mgmt-net=192.168.251.9 |

[2018-09-10 06:05:52,424] 2628 INFO MainThread network_helper.ping_server:: All packets received by 192.168.251.9
[2018-09-10 06:05:52,424] 428 DEBUG MainThread ssh.exec_cmd:: Executing command...
[2018-09-10 06:05:52,424] 264 DEBUG MainThread ssh.send :: Send 'ping -c 3 192.168.251.11'
[2018-09-10 06:05:55,534] 391 DEBUG MainThread ssh.expect :: Output:
PING 192.168.251.11 (192.168.251.11) 56(84) bytes of data.
From 192.168.51.3 icmp_seq=1 Destination Host Unreachable
From 192.168.51.3 icmp_seq=2 Destination Host Unreachable
From 192.168.51.3 icmp_seq=3 Destination Host Unreachable

--- 192.168.251.11 ping statistics ---
3 packets transmitted, 0 received, +3 errors, 100% packet loss, time 2016ms
pipe 3