[pve-devel] [PATCH pve-docs v2 1/1] fabrics: add initial documentation for sdn fabrics

[Gabriel Goller]

Add initial documentation for the openfabric and ospf options.

Signed-off-by: Gabriel Goller <g.goller at proxmox.com>
---
 pvesdn.adoc | 206 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 206 insertions(+)

diff --git a/pvesdn.adoc b/pvesdn.adoc
index 5d5d27bfbc1f..414f39c5109e 100644
--- a/pvesdn.adoc
+++ b/pvesdn.adoc
@@ -517,6 +517,212 @@ Loopback:: Use a loopback or dummy interface as the source of the EVPN network
   (for multipath).
 
 
+[[pvesdn_config_fabrics]]
+Fabrics
+-------
+
+[thumbnail="screenshot/gui-datacenter-fabrics-overview.png"]
+
+Fabrics in {pve} SDN provide automated routing between nodes in a cluster. They
+simplify the configuration of underlay networks between nodes to form the
+foundation for SDN deployments.
+
+They automatically configure routing protocols on your physical network
+interfaces to establish connectivity between nodes in the cluster. This creates
+a resilient, auto-configuring network fabric that adapts to changes in network
+topology. These fabrics can be used as a full-mesh network for Ceph
+footnote:[Full Mesh Network for Ceph{webwiki-url}Full_Mesh_Network_for_Ceph_Server]
+(Note that currently you need to add the fabrics prefix to Ceph manually, so:
+`pveceph init --network 192.0.2.0/24`) or as an underlay network for EVPN
+deployments.
+
+Installation
+~~~~~~~~~~~~
+
+The FRR implementations of OpenFabric and OSPF are used, so first the `frr` and
+`frr-pythontools` packages must be installed:
+
+----
+apt update
+apt install frr frr-pythontools
+----
+
+Configuration
+~~~~~~~~~~~~~
+
+To create a Fabric, head over to Datacenter->SDN->Fabrics and click "Add
+Fabric". After selecting the preferred protocol, the fabric is created. With
+the "+" button you can select the nodes which you want to add to the fabric,
+you also have to select the interfaces used to communicate with the other nodes.
+
+Router-ID Selection
+^^^^^^^^^^^^^^^^^^^
+
+Each node in a fabric needs a unique router-ID, which is an IPv4 address in
+dotted decimal notation (e.g., 192.0.2.1). In OpenFabric this can also be an
+IPv6 address in the typical hexadecimal representation separated by colons
+(e.g., 2001:db8::1428:57ab). A dummy interface with the router-ID as address
+will automatically be created and will act as a loopback interface for the
+fabric (it's also passive by default).
+
+Loopback Prefix
+^^^^^^^^^^^^^^^
+
+You can specify a CIDR network range (e.g., 192.0.2.0/24) as a loopback prefix for the fabric. 
+When configured, the system will automatically verify that all router-IDs are contained within 
+this prefix. This ensures consistency in your addressing scheme and helps prevent addressing 
+conflicts or errors.
+
+[[pvesdn_openfabric]]
+OpenFabric
+~~~~~~~~~~
+
+OpenFabric is a routing protocol specifically designed for data center fabrics.
+It's based on IS-IS and optimized for the spine-leaf topology common in data
+centers.
+
+[thumbnail="screenshot/gui-datacenter-create-fabric-openfabric.png"]
+
+Configuration options:
+
+[[pvesdn_openfabric_fabric]]
+On the Fabric
+^^^^^^^^^^^^^
+
+Name:: This is the name of the OpenFabric fabric and can be at most 8 characters long.
+
+Loopback Prefix:: CIDR (IPv4 or IPv6) network range (e.g., 192.0.2.0/24) used to verify that
+all router-IDs in the fabric are contained within this prefix.
+
+Hello Interval:: Controls how frequently (in seconds) hello packets are sent to
+discover and maintain connections with neighboring nodes. Lower values detect
+failures faster but increase network traffic. This option is global on the
+fabric, meaning every interface on every node in this fabric will inherit this
+hello-interval property. The default value is 3 seconds.
+
+[[pvesdn_openfabric_node]]
+On the Node
+^^^^^^^^^^^
+
+[thumbnail="screenshot/gui-datacenter-create-node-openfabric.png"]
+
+Options that are available on every node that is part of a fabric:
+
+Node:: Select the node which will be added to the fabric. Only nodes that
+currently are in the cluster will be shown.
+
+
+Router-ID:: A unique IPv4 or IPv6 address used to generate the OpenFabric
+Network Entity Title (NET). Each node in the same fabric must have a different
+Router-ID, while a single node must use the same NET address across all fabrics
+(this consistency is automatically managed by {pve}).
+
+WARNING: When using IPv6 addresses, the last 3 segments are used to generate
+the NET. Ensure these segments differ between nodes.
+
+Interfaces:: Specify the interfaces used to establish peering connections with
+other OpenFabric nodes. Preferably select interfaces without pre-assigned IP
+addresses, then configure addresses in the IPv4/IPv6 column if needed. A dummy
+"loopback" interface with the router-id is automatically created.
+Interface-specific settings override the global fabric settings.
+
+On The Interface
+^^^^^^^^^^^^^^^^
+
+The following optional parameters can be configured per interface when enabling
+the additional columns:
+
+IP::: A IPv4 that should get automatically configured on this interface. Must
+include the netmask (e.g. /31)
+
+IPv6::: A IPv6 that should get automatically configured on this interface. Must
+include the netmask (e.g. /127).
+
+Passive::: When enabled, the interface will not form OpenFabric adjacencies but
+its networks will still be advertised.
+
+Hello Interval::: Controls how frequently (in seconds) hello packets are sent
+on this specific interface. Lower values detect failures faster but increase
+network traffic. The default value is 3 seconds.
+
+CSNP Interval::: Sets how frequently (in seconds) the node synchronizes its 
+routing database with neighbors. Lower values keep the network topology information 
+more quickly in sync but increase network traffic. The default value is 10 seconds.
+
+Hello Multiplier::: Defines how many missed hello packets constitute a failed
+connection. Higher values make the connection more resilient to packet loss but
+slow down failure detection. The default value is 10.
+
+WARNING: When you remove an interface with an entry in `/etc/network/interfaces`
+that has `manual` set, then the IP will not get removed on applying the SDN
+configuration.
+
+[[pvesdn_ospf]]
+OSPF
+~~~~
+
+OSPF (Open Shortest Path First) is a widely-used link-state routing protocol
+that efficiently calculates the shortest path for routing traffic through IP
+networks.
+
+[thumbnail="screenshot/gui-datacenter-create-fabric-ospf.png"]
+
+Configuration options:
+
+[[pvesdn_ospf_fabric]]
+On the Fabric
+^^^^^^^^^^^^^
+
+Area:: This specifies the OSPF area identifier, which can be either a 32-bit
+signed integer or an IP address. Areas are a way to organize and structure OSPF
+networks hierarchically, with Area 0 (or 0.0.0.0) serving as the backbone area.
+
+Loopback Prefix:: CIDR (only IPv4) network range (e.g., 192.0.2.0/24) used to
+verify that all router-IDs in the fabric are contained within this prefix.
+
+Area:: This specifies the OSPF area identifier, which can be either an 32-bit
+signed integer or an IP address. Areas are a way to organize and structure OSPF
+networks hierarchically, with Area 0 (or 0.0.0.0) serving as the backbone area.
+
+[[pvesdn_ospf_node]]
+On the Node
+^^^^^^^^^^^
+
+[thumbnail="screenshot/gui-datacenter-create-node-ospf.png"]
+
+Options that are available on every node that is part of a fabric:
+
+Node:: Select the node which will be added to the fabric. Only nodes that
+are currently in the cluster will be shown.
+
+Router-ID:: A unique IPv4 address used to identify this router within the OSPF
+network. Each node in the same fabric must have a different Router-ID.
+
+Interfaces:: Specify the interfaces used to establish peering connections with
+other OSPF nodes. Preferably select interfaces without pre-assigned IP
+addresses, then configure addresses in the IPv4 column if needed. A dummy
+"loopback" interface with the router-id is automatically created.
+
+On The Interface
+^^^^^^^^^^^^^^^^
+The following optional parameter can be configured per interface when enabling
+the additional columns:
+
+IP::: A IPv4 that should get automatically configured on this interface. Must
+include the netmask (e.g. /31)
+
+Passive::: When enabled, the interface will not form OSPF adjacencies but
+its networks will still be advertised.
+
+Unnumbered::: When enabled, sets the OSPF network type to point-to-point,
+allowing adjacencies to form over interfaces without explicitly assigned IP
+addresses. This *must* be enabled for interfaces where there is no address
+configured in the IPv4 column.
+
+WARNING: When you remove an interface with an entry in `/etc/network/interfaces`
+that has `manual` set, then the IP will not get removed on applying the SDN
+configuration.
+
 [[pvesdn_config_ipam]]
 IPAM
 ----
-- 
2.39.5