Details Direct service and summarizes key parameters, requirements, and reference information. It covers Direct Service is a ULB feature that delivers service traffic to an eligible backend.
Direct Service is a ULB feature that delivers service traffic to an eligible backend application pod while preserving the configured service IP address and port. It uses the node-ingress and pod-network resources configured through the ULB Cluster Policy and ULB Network Policy, as described in their respective sections. The backend pod template references the generated Multus NAD. When Multus creates the pod network, each configured Direct Service address is assigned to a separate ULB-managed interface inside every attached pod. This provides consistent service delivery whether the selected backend is on the entry node or another participating node.
When traffic arrives on an operational node interface, the ULB ingress eBPF program matches the destination service IP address, port, and protocol to a Direct Service LoadBalancer. It selects an eligible backend or reuses an existing valid placement, then delivers the unchanged packet to a local backend or forwards it to the participating node hosting the selected backend. Response traffic follows the ULB-managed return path toward the originating client or peer.