IPv6 subnets
slaac, dhcpv6-stateful and dhcpv6-stateless modes; same validations and errors as Python
Architecture
Networking: Neutron, OVN and OVS
Neutron in Go writes the logical model into OVN; ovn-controller and Open vSwitch switch the packets of the VMs and containers.
Who does what, layer by layer
- Neutron (Go)
API, MariaDB database, IPAM, policies; writes networks, ports, routers, security groups and floating IPs into OVN; a reconciler fixes drift
- OVN Northbound
Logical model: switches, routers, ports, ACLs and Port_Groups, NAT (SNAT, floating IPs), DHCP, Octavia load balancers
- ovn-northd + Southbound
Compiles the model into logical flows; binds each port to a node (chassis); schedules the HA gateways
- ovn-controller
On each node: programs br-int with OpenFlow, Geneve tunnels, answers DHCP, ARP and RA locally
- Open vSwitch
ovsdb-server and ovs-vswitchd: br-int bridge, kernel or userspace datapath, switches the packets of VMs and containers
IPv6 in Neutron
Router advertisements
ipv6_ra_configs on the OVN router ports: addressing, MTU, metadata route
Agentless DHCPv6
DHCPv6 options written into OVN; SLAAC addresses computed with EUI-64
Security groups
ip6 and icmp6 ACLs, IPv6 remote groups, IPv6 egress rules by default
Routing
Default route ::/0 to the external gateway; SNAT and floating IPs stay IPv4
VM isolation
IPv6 forwarding off in the Pod, IPv6 disabled on the host veth
Not verified yet: tenant IPv6 subnets on the real lab data plane, Tempest's Octavia IPv6 tests. Prefix delegation, deprecated upstream, is not carried over.
OVSDB view
Full screen