Unable to change default subnets used by TCA management cluster

Products

• VMware Telco Cloud Automation
• VMware Telco Cloud Platform - 5G Edition

Issue/Introduction

Creation of the TCA management cluster fails when it is unable to access the IP assigned to the bootstrap VM.

Example: If you use DHCP subnet we are using is 100.X.X.0/26. This overlaps with the default cluster subnet that is used by Kubernetes - CLUSTER_CIDR: 100.96.0.0/11.

Environment

Telco Cloud Automation (TCA) 

Cause

By default TCA uses subnet  100.64.0.0/10 as a reserved space for cluster networks. This means any IPs on that range will be assumed to be internal to TCA.

This address space is for a special purpose of CGNAT as defined on rfc6598

Resolution

Do not use the IP range 100.64.0.0/10 addresses or modify the TCA Management Cluster IP Range. They are always meant to be internal to TCA.