Windows containers are created in a different network overlay from TAS network overlay

Products

• VMware Tanzu Application Service for VMs

Issue/Introduction

This article discuss why Windows container are created in a different network overlay from TAS network overlay. 

For this KB, We would assume that TAS configuration container overlay subnet range is set 10.242.0.0/16.

And we have pushed a sample app to windows stack:

cf push test-app -p . -b binary_buildpack -s windows

Once the container is created, ssh into the container and check for its IP:



The container's IP  is 172.30.2.237 which is outside of TAS network overlay.

Environment

Product Version: 2.13

Cause

This is an expected behaviour. TAS for Windows by default will use 172.30.0.0/22 range so containers IPs so it will be using a different overlay from TAS. 

TASW will create containers with IP Range: 172.30.0.1 ~ 172.30.3.254

You can customize network overlay for TAS for windows starting from version 3.0 .
For version TASW 2.13 and earlier its not possible to customize network overlay.