Centralized Routing on Single Rack Small Data
Center Leaf Pair (not Border Leaf Pair)
The following items are required before you configure centralized routing on Single Rack
Small Data Center Leaf Pair.
- The device-role (leaf or border-leaf) are specified during the addition of the
devices to the fabric, prior to the “fabric configure”.
- Border-Leaf pair can exist in a Clos
or Small Data Center fabric irrespective of the VRFs instantiated in the fabric are
distributed or centralized.
- Device role border-leaf implies the leaf pair used at the edge (border) of the
fabric, and not restricted to the centralized routing.
- Tenant (PO, VRF, EPG, or BGP)
provisioning happens on a configured fabric.
- Only the Border-Leaf devices can act as Centralized Routers.
- Default routing-type for a VRF is “distributed” and you need to explicitly provide
the value “centralized” if needed.
- During creation of VRF as a CR
(Centralized Router), XCO must instantiate the VRF on a pair of Border-Leaf
devices.
- If the fabric (Clos or Small Data
Center) has only one pair of Border-Leaf devices, then the same pair will be chosen
as the designated CRs (Centralized Routers) for the VRF. Otherwise, you must
explicitly provide the Border-Leaf devices as the designated CRs (Centralized
Routers) during the creation of VRF.
- XCO is designed to expand or compress
with the addition or deletion of racks (rack = MCT-pair) as per your
requirement.
- XCO cannot determine “a given fabric
is a single rack small data center fabric and can never be expanded beyond that”.
Hence there is no specific automation for a single-rack use case.
- For CR on a single rack small data
center fabric, as a best practice, you must configure the fabric with the
device-role = border-leaf for both the MCT nodes.
- Using the Day 1 Centralized Routing
provisioning on a “Day 0 Configured Single Rack Leaf Small Data Center
Fabric” results in failure because CR can be instantiated only on the
border-leaf pair of small data center fabric.
- You cannot recreate the fabric with device-role = border-leaf.
Fabric Setting for a Single Rack
Deployment
- Use the following command to
configure a single-rack-deployment when you update a fabric
setting:
efa fabric setting update --name <non-clos-fabric-name> --single-rack-deployment <Yes|No>
- The fabric setting is applicable
only for a Small Data Center fabric.
- Default value of
single-rack-delployment is No.
- Single Rack Deployment
- When the value of
single-rack-deployment is Yes and the fabric is configured,
- You cannot modify
the value of single-rack-deployment from Yes to No.
- The state is used
as an indicator to XCO that “a given fabric is a single rack
non-Clos fabric and will never be expanded beyond that”, so that
XCO can have specific automation for the specific scenario of
allowing the non-border-leaf rack to act as CR (Centralized
Router) for single rack small data center leaf pair
deployments.
- You cannot expand
such a fabric. If you intend to expand such a fabric, then you
must delete the fabric and recreate the same with
“single-rack-deployment = No”.
- When the value of
single-rack-deployment is Yes and the fabric is not configured,
- You can modify
the single-rack-deployment value from Yes to No.
- Multi Rack Deployment
- When the value of
single-rack-deployment is No and the fabric is configured or
not-configured,
- You can modify
the value of single-rack-deployment from No to Yes, provided the
existing number of rack in the fabric is 1.
- Fabric Device Add
- Validations are done to ensure the number of racks in the given fabric
adhere to the fabric settings.
