How to migrate Spring Cloud Services for VMware Tanzu service instances backend app stack from cflinuxfs3 to cflinuxfs4

Products

• VMware Tanzu Platform

Issue/Introduction

Tanzu Platform Elastic Application Runtime, formerly Tanzu Application Service, provides stacks which contain the OS layer dependencies that are available to your app. The Linux stack is called `cflinuxfsX`, where X is a number

• cflinuxfs3 corresponds to an Ubuntu Bionic 18.04 container
• cflinuxfs4 corresponds to an Ubuntu Jammy 22.04 container

Since the cflinuxfs3 is end of support, the cflinuxfs4 will be the default stack of newly created services and applications. 

For previously created SCS (Spring Cloud Services for VMware Tanzu) service instances, this article is about how to migrate the backend app stack from cflinuxfs3 to cflinuxfs4.

Environment

Spring Cloud Services for VMware Tanzu v3.2 and above

Resolution

This article walks you through the ways to migrate SCS service instance backend app stack from cflinuxfs3 to cflinuxfs4. There are a few options for migration.

As an operator

As platform operator,you have two options - with stack auditor plugin or "Upgrade All Instances" errand. 

With stack auditor, you will have to migrate apps running under the `p-spring-cloud-services` org and `instances` space. You can locate those apps with command: 

cf audit-stack | grep -e '^p-spring-cloud-services'

then follow the instructions to change app stack. 

The "Upgrade All Instances" errand redeploys service instance backend apps with the configured stack (default as cflinuxfs4). 

As a Developer

Developer can update their own SCS service instance backend app stack with 

cf update-service <service name> -c '{"upgrade": true}'

it picks up the default stack of Tanzu Platform Elastic Application Runtime(which should be cflinuxfs4 and can be confirmed with `cf -v stacks`) and restages apps.