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IPv6 in OpenStack

OpenStack offers comprehensive support for IPv6, enabling the operation of pure IPv6 or dual-stack networks (IPv4 and IPv6). This allows you to build modern, future-proof network architectures for your virtual machines (VMs).

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Currently, IPv6 is limited to Region 2 CH-GE1.

Address Configuration

Instances in an IPv6-enabled network can obtain their addresses in various ways. OpenStack supports the following modes for address assignment:

  • SLAAC (Stateless Address Autoconfiguration): VMs configure their own addresses based on 'Router Advertisements' (RA) sent by the router. This is a common method for stateless address assignment.
  • DHCPv6-stateless: In this mode, address assignment is complemented by SLAAC. A DHCPv6 server provides additional configuration information, such as DNS servers, without managing the addresses themselves.
  • DHCPv6-stateful: In this mode, a DHCPv6 server assigns addresses and other configuration parameters to the VMs. This allows for centralized and stateful management of IP addresses.

In our environment, a /64 network from a predefined pool is assigned to you for IPv6 usage. You can then use this for addressing your instances.

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Our Openstack currently supports only DHCPv6-stateless !

A detailed guide on how to create an IPv6 network using the Horizon dashboard can be found here: Guide: Create an IPv6 Network in Horizon

Dual-Stack Operation

One of OpenStack's strengths is the easy setup of dual-stack networks. You can create an IPv4 and an IPv6 subnet within the same network, allowing your instances to be simultaneously reachable via both protocols.

Important Notes

Although IPv6 is largely supported, there are some specifics to consider. For example, the functionality of Floating IPs, which are primarily designed for IPv4, is not available in the same way in pure IPv6 operation. Consequently, certain services like Load Balancers, which rely on Floating IPs, must be configured differently for IPv6.