keep-existing-bindings

Keeping existing CF app service bindings during update

Table of Contents

• Overview
• Official Documentation
• Try out
  • Initial deployment
  • Manually bind service instance
  • Re-deply to simulate update

Overview

This example shows how to preserve manually created service bindings, during an MTA deployment, that are created outside of the MTA. A real use case for that is a multi-tenant scenario where bindings are created during tenant onboarding of a multitenant application, and those bindings are not maintained by MTA deployment.

Modelled via a module level parameter keep-existing and parameter option service-bindings:

modules:
  - name:...
    parameters:
      keep-existing:
        service-bindings: true

Official Documentation

• SAP Help Portal: Modules → Table Module-Specific Parameters

Note	See mta.yaml or mtad.yaml in the current directory.

Try out

Initial deployment

In that part the MTA will be initially deployed when two applications are deployed and one service instance. There is not binding between them.

directly from an mtad.yaml

  $ cf deploy ./ -f ;

or start from an mta.yaml:

  $ mbt build -p cf -t . ;
  $ cf deploy a.cf.app_0.0.0.mtar -f ;

Manually bind service instance

  $ cf bind-service cf-app-keeping-bindings dummy-service
  $ cf bind-service cf-app-resetting-bindings dummy-service

Examine the result

  $ cf services
Getting services in org ...
name           service       ... bound apps                                         ...
dummy-service  user-provided     cf-app-keeping-bindings, cf-app-resetting-bindings

Re-deply to simulate update

  $ cf deploy -f ;
  # or
  $ cf deploy a.cf.app_0.0.0.mtar -f ;

Examine the result

Verify that app cf-app-keeping-bindings has the binding preserved and app cf-app-keeping-bindings has lost the binding.

  $ cf services
Getting services in org ...
name           service       ... bound apps                                         ...
dummy-service  user-provided     cf-app-keeping-bindings