Comment 5 for bug 1597461

We've been able to reproduce this internally as well, without even rebooting. I'll add the info here since the multiple active routers seems to be issue, not necessarily the reboot.

$ neutron router-create --tenant-id 8beb0d59ef0a448d9e0da918931f3c22 --distributed True --ha True r1
Created a new router:
+-------------------------+--------------------------------------+
| Field | Value |
+-------------------------+--------------------------------------+
| admin_state_up | True |
| availability_zone_hints | |
| availability_zones | |
| description | |
| distributed | True |
| external_gateway_info | |
| ha | True |
| id | cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b |
| name | r1 |
| routes | |
| status | ACTIVE |
| tenant_id | 8beb0d59ef0a448d9e0da918931f3c22 |
+-------------------------+--------------------------------------+

$ neutron router-gateway-set cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b 72e69016-085b-40a5-94aa-bdacafd5a075
Set gateway for router cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b

$ neutron net-create n1
Created a new network:
+-------------------------+--------------------------------------+
| Field | Value |
+-------------------------+--------------------------------------+
| admin_state_up | True |
| availability_zone_hints | |
| availability_zones | |
| created_at | 2016-06-15T12:28:46 |
| description | |
| id | 5b644fea-50b7-49b3-b4b3-88a05509f9a0 |
| ipv4_address_scope | |
| ipv6_address_scope | |
| mtu | 1450 |
| name | n1 |
| router:external | False |
| shared | False |
| status | ACTIVE |
| subnets | |
| tags | |
| tenant_id | 8beb0d59ef0a448d9e0da918931f3c22 |
| updated_at | 2016-06-15T12:28:46 |
+-------------------------+--------------------------------------+

$ neutron subnet-create n1 99.99.99.0/24
Created a new subnet:
+-------------------+------------------------------------------------+
| Field | Value |
+-------------------+------------------------------------------------+
| allocation_pools | {"start": "99.99.99.2", "end": "99.99.99.254"} |
| cidr | 99.99.99.0/24 |
| created_at | 2016-06-15T12:29:01 |
| description | |
| dns_nameservers | |
| enable_dhcp | True |
| gateway_ip | 99.99.99.1 |
| host_routes | |
| id | b7f2e674-887d-4282-b671-6e8edb5f9524 |
| ip_version | 4 |
| ipv6_address_mode | |
| ipv6_ra_mode | |
| name | |
| network_id | 5b644fea-50b7-49b3-b4b3-88a05509f9a0 |
| subnetpool_id | |
| tenant_id | 8beb0d59ef0a448d9e0da918931f3c22 |
| updated_at | 2016-06-15T12:29:01 |
+-------------------+------------------------------------------------+

$ neutron router-interface-add cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b b7f2e674-887d-4282-b671-6e8edb5f9524
Added interface 1b410fb9-6e87-49d3-a79d-f8226dd83325 to router cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b.

$ neutron l3-agent-list-hosting-router cb484e8c-4de6-4a50-89d6-e8c53e6f6d4b
+--------------------------------------+-----------------------+----------------+-------+----------+
| id | host | admin_state_up | alive | ha_state |
+--------------------------------------+-----------------------+----------------+-------+----------+
| 3807a338-66c1-4812-afe8-30486ce7b593 | hlm004-cp1-c1-m1-mgmt | True | :-) | active |
| 7e88f881-b831-48a0-87ca-f9b967e91409 | hlm004-cp1-c1-m3-mgmt | True | :-) | active |
+--------------------------------------+-----------------------+----------------+-------+----------+