The platform uses software-defined networking (SDN) to handle communications for the cluster. SDN includes container-to-container connections, pod-to-pod connections, ingress to pod connections, and pod to external services like ObjectScale, PowerScale, and ECS. These network services are provided through the Kubernetes Container Network Interface (CNI) and supported by CNI-compatible network plugins.
Each physical node in the cluster is assigned an IP address for its connection to the Cluster data network. Each connection uses a pair of physical network ports that are bonded with IEEE 802.3ad Dynamic Link Aggregation. This configuration provides both load balancing across physical links, and fault tolerance if a link fails. All networking above this layer is software-defined and uses IP addresses that are private to the cluster.
When applications running on the cluster request IP addresses, the addresses are allocated from the tenants IP pool. The IP pool specifies both the range of addresses available and the CNI driver to use. Dell Technologies recommends using the OVN-Kubernetes network plug-in for most use cases, since it provides the best support for inbound access to applications from outside the cluster.
Inbound network access to applications is handled through a Kubernetes NodePort or LoadBalancer service. The NodePort or LoadBalancer configuration is specified in the application configuration and includes the external and internal port number mapping. Outbound network access from applications is handled through IP routing that is based on the destination.
See the Red Hat OpenShift Container Platform 4.12 on Intel-powered Dell Infrastructure Design Guide for more details about OpenShift Container Platform networking.