Verified on Fuel 8.0 MU-5

root@node-1:~# neutron router-list
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| id                                   | name     | external_gateway_info                                                                                                                                                                    | distributed | ha    |
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39 | router04 | {"network_id": "e105957e-0a29-498a-9291-f94bdf5a60cb", "enable_snat": true, "external_fixed_ips": [{"subnet_id": "1df84671-cd94-4eaa-8334-c5f99ad7be19", "ip_address": "10.109.8.128"}]} | False       | False |
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
root@node-1:~# 
root@node-1:~# 
root@node-1:~# 
root@node-1:~# neutron router-gateway-set --disable-snat d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39 e105957e-0a29-498a-9291-f94bdf5a60cb
Set gateway for router d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39
root@node-1:~# 
root@node-1:~# neutron router-list
+--------------------------------------+----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| id                                   | name     | external_gateway_info                                                                                                                                                                     | distributed | ha    |
+--------------------------------------+----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39 | router04 | {"network_id": "e105957e-0a29-498a-9291-f94bdf5a60cb", "enable_snat": false, "external_fixed_ips": [{"subnet_id": "1df84671-cd94-4eaa-8334-c5f99ad7be19", "ip_address": "10.109.8.128"}]} | False       | False |
+--------------------------------------+----------+-------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
root@node-1:~# 
root@node-1:~# 
root@node-1:~# 
root@node-1:~# neutron router-gateway-set --enable-snat d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39 e105957e-0a29-498a-9291-f94bdf5a60cb                                                 
Set gateway for router d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39
root@node-1:~# 
root@node-1:~# 
root@node-1:~# neutron router-list
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| id                                   | name     | external_gateway_info                                                                                                                                                                    | distributed | ha    |
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+
| d59c36b4-c7ca-4ce4-999d-ee67c3b5bb39 | router04 | {"network_id": "e105957e-0a29-498a-9291-f94bdf5a60cb", "enable_snat": true, "external_fixed_ips": [{"subnet_id": "1df84671-cd94-4eaa-8334-c5f99ad7be19", "ip_address": "10.109.8.128"}]} | False       | False |
+--------------------------------------+----------+------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------+-------------+-------+