A specific handler component is deployed for the OVN Kubernetes CNI plugin.
OVN is a project that builds on top of Open vSwitch providing a rich high level API for describing virtual network components like Logical Routers, Logical Switches, Load balancers, Logical Ports. OVN Kubernetes is a Cloud Management System Plugin (CMS plugin) which manages OVN resources to setup networking for Kubernetes clusters.
The OVN Kubernetes handler watches for Submariner
Endpoints and Kubernetes
Nodes and interfaces with the OVN databases (OVN NorthDB and SouthDB) to store and
create OVN resources necessary for Submariner, including:
A logical router named
submariner_router that handles the communication
to remote clusters and has a leg on the network which can talk to the
ovn-k8s-sub0 interface on the Gateway node. This router is pinned to
the active Gateway chassis.
The Ovn-Kubernetes Specific OVN Load Balancer Group (which contains all of the
cluster’s service VIPs) is added to the
submariner_routerin order to ensure
total service connectivity.
OVN Logical Router Static Routes added to the
submariner_router to ensure
local traffic destined for remote clusters and remote traffic destined for local
resources is routed correctly.
OVN Logical Router Policies added to the existing
ovn_cluster_router which redirect
traffic targeted for remote routers through the
submariner_join logical switch that connects the
Requires OVN NorthBound DB version 6.1.0+, available with OCP 4.11.0+
The following diagram illustrates the required Submariner OVN architecture transposed
on the native OVN-Kubernetes managed OVN architecture and components. The specific
networkpluginsyncer managed OVN components are boxed in green.