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new eca7c584 IPv6 corrections (#628)
eca7c584 is described below
commit eca7c584ce346e9d32d3fe5063e010dc9638851d
Author: Jithin Raju <[email protected]>
AuthorDate: Wed Sep 2 00:07:27 2026 +0530
IPv6 corrections (#628)
* Update unsupported features list in ipv6.rst
Remove the security group from IPv6 limitations
* Update IPv6 support information in documentation
Clarified IPv6 support details for shared networks, including deployment
models and limitations.
* IPv6 page formatting
* Update IPv6 Shared Network documentation with address assignment and
routing details
* Update IPv6 support
* Clarify that IPv6 Start IP and End IP are optional parameters
* IPv6: fix heading level for IPv6 Address Assignment and Routing section
Use the subsection (#) underline instead of the page-title (=) underline so
the section nests correctly under 'Shared network' instead of rendering as a
top-level sibling that detaches the following sections.
---
source/plugins/ipv6.rst | 66 +++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 59 insertions(+), 7 deletions(-)
diff --git a/source/plugins/ipv6.rst b/source/plugins/ipv6.rst
index 79078f36..61d81df0 100644
--- a/source/plugins/ipv6.rst
+++ b/source/plugins/ipv6.rst
@@ -20,11 +20,65 @@ CloudStack has limited IPv6 support. It supports IPv6 for
shared and isolated ne
Shared network
--------------
-With IPv6 support, Instances in shared networks can obtain both IPv4 and IPv6
addresses from the DHCP
-server. You can deploy Instances either in a IPv6 or IPv4 network, or in a
-dual network environment. If IPv6 network is used, the Instance generates a
-link-local IPv6 address by itself, and receives a stateful IPv6 address
-from the DHCPv6 server.
+When IPv6 is enabled, Instances deployed in a Shared Network can obtain both
IPv4 and IPv6 addresses.
+CloudStack supports the following deployment models:
+
+- IPv4-only networks
+- Dual-stack networks (IPv4 + IPv6)
+
+In an IPv6-enabled network:
+
+- The Instance automatically generates a link-local IPv6 address.
+- A stateful IPv6 address is assigned through a DHCPv6 server when configured.
+
+.. note::
+ IPv6-only Shared Networks are not supported when using the Virtual Router
+ provider. In such environments, IPv6 must be deployed in a dual-stack
+ configuration.
+
+IPv6 Address Assignment and Routing
+###################################
+
+In Shared Networks, IPv6 address assignment and routing are provided by the
upstream network infrastructure, not by the CloudStack Virtual Router.
+
+When IPv6 is enabled on a Shared Network:
+
+- Instances automatically generate a link-local IPv6 address.
+- IPv6 global or ULA addresses are typically assigned via:
+
+ - SLAAC (Router Advertisements) from the upstream router, or
+ - An external DHCPv6 server (if present in the upstream network).
+
+- CloudStack does not provide DHCPv6 services in Shared Networks via the
Virtual Router.
+
+SLAAC-based IPv6 Address Allocation in Shared Networks
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+In shared networks with IPv6 enabled:
+
+- CloudStack allocates instance NICs with SLAAC-based IPv6 addresses
calculated from the IPv6 CIDR and the MAC address of the NIC.
+- This calculated SLAAC address matches the IPv6 address that the guest OS
automatically assigns to the instance.
+- When creating or configuring IPv6 ranges for shared networks, the **IPv6
Start IP** and **IPv6 End IP** parameters are optional in both the UI and API
(e.g., ``createVlanIpRange``) and are **not used** for SLAAC-based address
allocation in shared networks.
+- If provided, these parameters should be filled with dummy IP addresses
within the same IPv6 subnet (for example, any two valid addresses from your
IPv6 CIDR).
+- These optional parameters are reserved for potential future use.
+
+Important Notes
+~~~~~~~~~~~~~~~
+
+- In Shared Networks, the Virtual Router does not act as the IPv6 gateway.
+- IPv6 default routing is determined entirely by upstream infrastructure.
+- CloudStack does not control IPv6 Router Advertisements in Shared Networks.
+- IPv6-only Shared Networks using the Virtual Router provider are not
supported.
+
+Operational Implications
+~~~~~~~~~~~~~~~~~~~~~~~~
+
+For IPv6 to function correctly in a Shared Network:
+
+- The upstream network must advertise the IPv6 prefix using Router
Advertisements (SLAAC), or
+- An external DHCPv6 server must be present.
+- The upstream router must provide the IPv6 default gateway.
+- CloudStack will not automatically generate or manage IPv6 gateway
functionality in this mode.
IPv6 is supported only on KVM and XenServer hypervisors. The IPv6
support is only an experimental feature.
@@ -92,8 +146,6 @@ Limitations
The following are not yet supported:
-#. Security groups
-
#. User Data and metadata
#. Passwords
