Contiv is an open-source networking plug-in module for container infrastructure. Contiv provides an infrastructure for application-oriented network policies and support for a range of multiple networking modes. These include:
A configurable set of overlay networking modes.
Physical networking modes.
Support for industry-leading hardware.
OKD can use Contiv for networking containers instead of the default OpenShift SDN.
Contiv configuration instructions are forthcoming.
Each node within the cluster runs a Contiv agent called netplugin while the master hosts run the Contiv controller (called netmaster), along with supporting control plane components (such as etcd).
Together the components of Contiv (netmaster and netplugin) handle key networking functions for OKD including:
Assigning IP addresses to each container pod on each cluster node.
Creating and managing multiple separate container network instances for different groups of containers.
Configuring the network forwarding layer components for layer two or layer three forwarding.
Configuring and enforcing a range of network policies.
Providing management interfaces (including both CLI and GUI) to configure and manage Contiv-specific features and configurations.
Providing an infrastructure for role-based controls that allow for multiple role-based network operations workflows.
Contiv uses the Container Network Interface (CNI) to interface with OKD and Kubernetes. A key value store based on etcd is used to store Contiv-specific state information. This is in addition to and separate from the instance of etcd used by other components in the system, including OKD itself.