Comment 1 for bug 1904711

Tested on train on a BGP setup like the one above and it all worked correctly with the following patches applied:
Tripleo-ansible -> https://review.opendev.org/763053
THT -> https://review.opendev.org/763064

TASK [tripleo_nodes_validation : Check Default IPv4 Gateway availability] ******
Wednesday 18 November 2020 08:31:21 +0000 (0:00:00.765) 0:04:47.918 ****
ok: [ctrl-1-0] => {"changed": false, "cmd": ["ping", "-w", "10", "-c", "1", "100.64.0.1"], "delta": "0:00:00.006779", "end": "2020-11-18 08:3
1:21.924376", "rc": 0, "start": "2020-11-18 08:31:21.917597", "stderr": "", "stderr_lines": [], "stdout": "PING 100.64.0.1 (100.64.0.1) 56(84
) bytes of data.\n64 bytes from 100.64.0.1: icmp_seq=1 ttl=64 time=0.250 ms\n\n--- 100.64.0.1 ping statistics ---\n1 packets transmitted, 1 r
eceived, 0% packet loss, time 0ms\nrtt min/avg/max/mdev = 0.250/0.250/0.250/0.000 ms", "stdout_lines": ["PING 100.64.0.1 (100.64.0.1) 56(84)
bytes of data.", "64 bytes from 100.64.0.1: icmp_seq=1 ttl=64 time=0.250 ms", "", "--- 100.64.0.1 ping statistics ---", "1 packets transmitte
d, 1 received, 0% packet loss, time 0ms", "rtt min/avg/max/mdev = 0.250/0.250/0.250/0.000 ms"]}

Ussuri backports:
Tripleo-ansible -> https://review.opendev.org/763052
THT -> https://review.opendev.org/763058

Train backports:
Tripleo-ansible -> https://review.opendev.org/763053
THT -> https://review.opendev.org/763064