This section describes how to scale out the Dell EMC Ready Architecture for Red Hat OpenShift Container Platform v3.11.
Container solutions can be scaled by adding multiple application and storage nodes. Your solution might contain multiple racks of servers. To create a non-blocking fabric to meet the needs of the micro-services data traffic, we used a leaf-spine network.
The following concepts apply to layer 2 and layer 3 leaf-spine topologies:
Dell Networking uses two leaf switches at the top of each rack, configured as a VLT pair. VLT allows all connections to be active while also providing fault tolerance. As administrators add racks to the data center, two leaf switches configured for VLT are added to each new rack.
The total number of leaf-spine connections is equal to the number of leaf switches multiplied by the number of spine switches. You can increase the bandwidth of the fabric by adding connections between leaves and spines as long as the spine layer has capacity for the additional connections.
In a layer 3 leaf-spine network, traffic is routed between leaves and spines. The layer 3/layer 2 boundary is at the leaf switches. Spine switches are never connected to each other in a layer 3 topology. Equal cost multipath routing (ECMP) is used to load balance traffic across the layer 3 network. Connections within racks from hosts to leaf switches are layer 2. Connections to external networks are made from a pair of edge or border leaves, as shown in the following figure.
Figure 10. Leaf-spine network configuration