Changing Windows Stacks

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This topic explains how to restage apps on a new Windows stack. It also provides a description of stacks and lists the supported Windows stacks on Pivotal Application Service for Windows (PASW) v2.6.

To restage a Windows app on a new Linux stack, see Changing Stacks.

You can also use the Stack Auditor plugin for the Cloud Foundry Command Line Interface (cf CLI) when changing stacks. See Using the Stack Auditor Plugin.

Overview

A stack is a prebuilt root file system (rootfs) that supports a specific operating system. For example, Linux-based systems need /usr and /bin directories at their root and Windows needs /windows. The stack works in tandem with a buildpack to support apps running in compartments. Under Diego architecture, cell VMs can support multiple stacks.

Note: Docker apps do not use stacks.

Available Stacks

If you push your PASW v2.6 app to a Windows stack, you must use windows. The windows2016 stack is not supported on PASW.

Restaging Apps on a New Stack

For security, stacks receive regular updates to address Common Vulnerabilities and Exposures (CVEs). Apps pick up on these stack changes through new releases of PASW. However, if your app links statically to a library provided in the rootfs, you may have to manually restage it to pick up the changes.

It can be difficult to know what libraries an app statically links to, and it depends on the languages you are using. One example is an app that uses a Ruby or Python binary, and links out to part of the C standard library. If the C library requires an update, you may need to recompile the app and restage it.

To restage an app on a new stack, do the following:

  1. Use the cf stacks command to list the stacks available in a deployment.

    $ cf stacks
    Getting stacks in org MY-ORG / space development as developer@example.com...
    OK
    
    name            description
    windows2016     Windows Server 2016
    windows         Windows Server
    
  2. To change your stack and restage your app, run the following command:

    cf push MY-APP -s STACK-NAME
    

    Where:

    • MY-APP is the name of the app.
    • STACK-NAME is the name of the new stack.

    For example, to restage your app on the windows stack, run cf push MY-APP -s windows:

    $ cf push MY-APP -s windows
    Using stack windows...
    OK
    Creating app MY-APP in org MY-ORG / space development as developer@example.com...
    OK
    ...
    requested state: started
    instances: 1/1
    usage: 1G x 1 instances
    urls: MY-APP.cfapps.io
    last uploaded: Wed Apr 8 23:40:57 UTC 2015
        state    since                    cpu    memory        disk
    #0  running  2015-04-08 04:41:54 PM   0.0%   57.3M of 1G   128.8M of 1G
    

Stacks API

For API information, see the Stacks section of the Cloud Foundry API Documentation.