Kubernetes – CNI plugin

On this presentation, I talk about on how kubernetes enable network communications between pods on different nodes using multiple Containers Network Interface (CNI) plugins

• Flat network

• All the pods should have an IP

• Traffic should flow to any direction

• no NAT : All the containers can communicate with each other directly without NAT

Pod to Pod Communications

we can enable pod 2 pod communication on L2 (Switching), L3 (Routing) or an Overlay Network. Pod 2 pod communication running on the same node is by IP L3. More commons scenarios are pod 2 pod on different nodes or networks.

• Calico one of the best performance network plugin as enable L3 network connectivity that uses BGP to route package between hosts. In addition Calico has the strongest network policy configurations

• Weave Net creates a mesh overlay network between each of the nodes in the cluster. Weave also provides strong network policy capability.

• Canal: Combination of best of Flannel and Calico, uses overlay network while still maintain a strong network policy capability.

• Flannel plugin uses an L3 overlay network. (VXLAN). It’s one of the easiest plugin to be installed and configured.

• NSX-t Plugin uses an overlay network VXLANs and runs on each Kubernetes node. It monitors container life cycle events, connects a container interface to the guest vSwitch, and programs the guest vSwitch to tag and forward container traffic between the container interfaces and the VNIC.