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This topic explains how to restage apps on a new stack. It also provides a description of stacks and lists the supported stacks on VMware Tanzu Application Service for VMs v2.9.
To restage a Windows app on a new Windows stack, see Changing Windows 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.
A stack is a prebuilt root file system (rootfs) that supports a specific operating system. For example, Linux-based systems need
/bin directories at their root. 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.
TAS for VMs v2.9 includes support for
cflinuxfs3. The Linux
cflinuxfs3 stack is derived from Ubuntu Bionic 18.04. For more information about supported libraries, see the GitHub stacks page.
For security, stacks receive regular updates to address Common Vulnerabilities and Exposures (CVEs). Apps pick up on these stack changes through new releases of TAS for VMs. 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:
cf stackscommand to list the stacks available in a deployment.
$ cf stacks Getting stacks in org MY-ORG / space development as email@example.com... OK name description cflinuxfs2 Cloud Foundry Linux-based filesystem - Ubuntu Trusty 14.04 LTS cflinuxfs3 Cloud Foundry Linux-based filesystem - Ubuntu Bionic 18.04 LTS
To change your stack and restage your app, run the following command:
cf push MY-APP -s STACK-NAME
- 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 stack
cf push MY-APP -s cflinuxfs3:
$ cf push MY-APP -s cflinuxfs3 Using stack cflinuxfs3... OK Creating app MY-APP in org MY-ORG / space development as firstname.lastname@example.org... 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
For API information, see the Stacks section of the Cloud Foundry API Documentation.