Network considerations

An OpenShift cluster uses an SDN layer to allow communication between workloads and cluster objects. The default plugin used with OpenShift at the time this book was written is OpenvSwitch (OvS), but OpenShift is also compatible (and supported) with the OVN-Kubernetes plugin. Check this link to better understand the differences between the plugins: https://docs.openshift.com/container-platform/latest/networking/openshift_sdn/about-openshift-sdn.html#nw-ovn-kubernetes-matrix_about-openshift-sdn.

Within the SDN, there are two virtual subnets—the first one has the Internet Protocol (IP) addresses that a Pod inside the cluster uses, while the second is always used when you create a service object. The default values for these subnets are listed in the following table:

Important Note

The preceding ranges are customizable during the platform installation process only! You cannot modify these after installation.

Make sure these...