Even when you allow IPv6's ICMP to passthrough the security rules for RA, instances won't know to use DHCPv6 because radvd doesn't have the appropriate flag set:
https://github.com/openstack/neutron/commit/4f3a9135acb561172f7af45bc82739d6dc49f23c
Enables the slaac/slaac+stateful (for DNS), but does not enable stateful at all, this flag is missing:
AdvManagedFlag on;
Even when you allow IPv6's ICMP to passthrough the security rules for RA, instances won't know to use DHCPv6 because radvd doesn't have the appropriate flag set:
https:/ /github. com/openstack/ neutron/ commit/ 4f3a9135acb5611 72f7af45bc82739 d6dc49f23c
Enables the slaac/slaac+ stateful (for DNS), but does not enable stateful at all, this flag is missing:
AdvManagedFlag on;