The Cluster Network Operator (CNO) deploys and manages the cluster network components in an OKD cluster. This includes deployment of the Container Network Interface (CNI) network plugin selected for the cluster during installation. For more information, see Cluster Network Operator in OKD.
The DNS Operator deploys and manages CoreDNS to provide a name resolution service to pods. This enables DNS-based Kubernetes Service discovery in OKD. For more information, see DNS Operator in OKD.
When you create your OKD cluster, pods and services running on the cluster are each allocated IP addresses. The IP addresses are accessible to other pods and services running nearby but are not accessible to external clients. The Ingress Operator implements the Ingress Controller API and is responsible for enabling external access to OKD cluster services. For more information, see Ingress Operator in OKD.
The External DNS Operator deploys and manages ExternalDNS to provide the name resolution for services and routes from the external DNS provider to OKD. For more information, see Understanding the External DNS Operator.
The Ingress Node Firewall Operator uses an extended Berkley Packet Filter (eBPF) and eXpress Data Path (XDP) plugin to process node firewall rules, update statistics and generate events for dropped traffic. The operator manages ingress node firewall resources, verifies firewall configuration, does not allow incorrectly configured rules that can prevent cluster access, and loads ingress node firewall XDP programs to the selected interfaces in the rule’s object(s). For more information, see Understanding the Ingress Node Firewall Operator
The Network Observability Operator is an optional Operator that allows cluster administrators to observe the network traffic for OKD clusters. The Network Observability Operator uses the eBPF technology to create network flows. The network flows are then enriched with OKD information and stored in Loki. You can view and analyze the stored network flows information in the OKD console for further insight and troubleshooting. For more information, see About Network Observability Operator.