[System Tests] Need to add test on check statistics of drops when size of packets is equal to MTU

[Andrey Sledzinskiy]

Test was requested due to https://bugs.launchpad.net/fuel/+bug/1402046

Steps:
1. Create and deploy cluster - Neutron GRE, HA, 3 controllers, 2 compute, 1 cinder
2. Create instance
3. Send packets from instance with size equal to MTU n times
4. Calculate statistics of the drops on the host
5. Assert that number of drops isn't lower than some number (percents of drops should be discussed)

[Artem Panchenko (apanchenko-8)]

We can use ICMP for such test, I propose the following scenario:

1. Create and deploy cluster - Neutron GRE, HA, 3 controllers, 2 computes, 1 cinder
2. Create instance, assign floating IP to it
3. Send ICMP packets from controller to instance with 1500 bytes size (Ethernet MTU)
4. If at least 7 responses on 10 requests are received assume test is passed, otherwise - failed

Command to send packets (it returns 0 if >6 replies are received):

ping -q -s 1472 -c 7 -w 10 ${FLOATING_IP}

I tested it on Ubuntu + NeutronGre with enabled DF for tunnels:

root@node-1:~# ping -q -s 1430 -c 7 -w 10 10.108.21.129 && echo "Test Passed" || echo "Test Failed"
PING 10.108.21.129 (10.108.21.129) 1430(1458) bytes of data.
--- 10.108.21.129 ping statistics ---
7 packets transmitted, 7 received, 0% packet loss, time 6007ms
rtt min/avg/max/mdev = 1.026/1.557/2.679/0.595 ms
Test Passed

root@node-1:~# ping -q -s 1472 -c 7 -w 10 10.108.21.129 && echo "Test Passed" || echo "Test Failed"
PING 10.108.21.129 (10.108.21.129) 1500(1528) bytes of data.
--- 10.108.21.129 ping statistics ---
10 packets transmitted, 0 received, 100% packet loss, time 9080ms
Test Failed

[OpenStack Infra (hudson-openstack)]

Fix proposed to branch: master
Review: https://review.openstack.org/147132

[OpenStack Infra (hudson-openstack)]

Reviewed: https://review.openstack.org/147132
Committed: https://git.openstack.org/cgit/stackforge/fuel-main/commit/?id=96fc4e3b470dd4b2f68f71aef4c3ce5fd6628117
Submitter: Jenkins
Branch: master

commit 96fc4e3b470dd4b2f68f71aef4c3ce5fd6628117
Author: asledzinskiy <email address hidden>
Date: Wed Jan 14 14:52:22 2015 +0200

    Add test on checking of drops when packet size is equal to MTU

    - Add neutron test on checking drops statistic when packet size
    is equal to MTU. Test is considered to be passed in case of more than
    7 successful responces

    Change-Id: I504bd60f782b8f64d99fd7b599ea64514456dad7
    Closes-Bug: #1402752