How to change app manifest attributes with zero down time manner by using the "cf v3-zdt-push" command

Products

• VMware Tanzu Application Service for VMs

Issue/Introduction

If using the "cf push --strategy rolling" command (i.e using v7 CF CLI), you can change some of the app manifest attributes by specifying in the app manifest file or via command line parameters with zero down time manner. However, if you are using the "cf v3-zdt-push" command (i.e. using v6 CF CLI) only, you can't do so because there are no ways to specify app manifest attributes with the command itself.

This article introduces how to change app manifest attributes with zero down time manner in some degrees by using the "cf v3-zdt-push" command and one more command in the case of using v6 CF CLI.

Environment

Product Version: 2.7

Resolution

You can change some of the app manifests with zero down time manner by following the steps below.

1. Change app manifest attributes in the manifest file of the target application.

2. Execute the following command for the purpose of applying changes in the manifest file.

cf v3-apply-manifest -f /path/to/manifest_file

3. Execute Rolling App Deployment.

cf v3-zdt-push <Target app name> ...

Note: "cf v3-apply-manifest" and "cf v3-zdt-push" commands are experimental. It may be changed without any notifications and it won't work as expected in some cases.

Note: It's not fully supported to change app manifest attributes with zero down time manner as of today (November, 2020) in both v6 CF CLI case and v7 CF CLI case. For example, you can't change the  health-check-type attribute with zero down time manner because all the application instances are restarted at the same time immediately when executing the "cf v3-apply-manifest" command. Before trying to change the specific app manifest attributes, we recommend you test whether the target app instances are really recreated with zero down time manner by observing with "cf app" command or from Apps Manager in your test environment.