Red Hat OpenShift 4.18 expands cloud-native networking

UDN improves the flexibility and segmentation capability of the default layer 3 Kubernetes pod network for VM administrators by enabling custom, isolated-by-default layer 2, layer 3, and localnet network segments, Lim explained. The segment can act as either primary or secondary networks for container pods and VMs. 

Lim noted that UDN custom network segmentation will enable organizations to do a few things. For example, it can be used as an easy way to create multi-tenant environments, creating a flat layer 2 network to be used as the VM primary network for live migrating VMs across nodes in the Kubernetes cluster.

BGP support extends cloud-native networking

OpenShift 4.18 also debuts enhanced user-defined networks with Border Gateway Protocol (BGP). BGP support is being added to UDN as a routing protocol for pod/VM addressability and VPN support. 

Lim explained that BGP enables dynamically exposing cluster-scoped network entities into a provider’s network, as well as programming BGP-learned routes from the provider’s network into OVN-Kubernetes. 

“This is particularly useful for integration with third-party load balancers needing direct access to backend OpenShift pods or VMs,” she said.

UDN will also add integrated support of Ethernet VPN (EVPN) to BGP, allowing for the extension of a UDN segment into one or more external networks. Lim noted that what that can enable for example, is a VM to be directly referenced by its (static) L2 network address, rather than requiring NAT translation at the cluster edge.