Lab 2.1: Significance of pod networking steps

bryonbaker

Hi,
Just getting into the labs and some of the steps come out of left field as there has been no content covering the concepts.
Why is it necessary to install the pod networking? What is happening in these steps? Which one is best to use?

And in the following example to join a node to the cluster, where does the IP address 10.128.0.3 come from?
Thanks

chrispokorni

Hi, the pod networking plugin solves the pod-to-pod communication requirement of the Kubernetes cluster.
The following links provide more details on the Kubernetes cluster networking, plugins, differences:
https://kubernetes.io/docs/concepts/cluster-administration/networking/
https://kubernetes.io/docs/concepts/cluster-administration/addons/

For the purpose of these labs, the Calico plugin is used because it is one of the many plugins providing networking and network policies support. This is installed by the k8sMaster.sh script.

The IP address 10.128.0.3 is displayed towards the end of the output on the Master node once the k8sMaster.sh script has completed initializing the Master node. This is the IP address that Minions will use to join the cluster.

Regards,
-Chris

chrispokorni

You are right, calico is needed for multi node clusters. In our case, we have the master and the second node. If you noticed on lab 2.1, the section on Configuring the Master, page 5, there are a few steps which instruct us to remove a taint. That taint removal enables the cluster to schedule pods on the master node as well.

Regards,
-Chris

bryonbaker

Thanks, that makes sense. But I thought we only needed calico if we had multiple nodes/hosts. I didn't see any configuration step that enabled pods on the master. Have I missed something?