Configuring Flannel CNI

Flannel is one of the most mature open source CNI projects for Kubernetes, developed by CoreOS. Flannel is a simple network model that may be used to cover the most common Kubernetes network configuration and management scenarios. It functions by building an overlay network that assigns an internal IP address subnet to each Kubernetes cluster node. The leasing and maintenance of subnets are handled by the flanneld daemon agent, which is packaged as a single binary for easy installation and configuration on Kubernetes clusters and distributions.

Disabling the HA cluster to enable the Flannel add-on

To set Flannel as the CNI, the high availability (HA) cluster must be disabled to set the CNI as Flannel. The following command execution output confirms that the HA cluster is disabled and Flannel CNI is set:

Figure 6.37 – Disabling the HA cluster to set Flannel CNI

Now that Flannel CNI is set up, we can deploy a sample application...