Uninstalling Decoupled Stack Tile Fails to Revert rootfs Version

Products

• VMware Tanzu Application Service
• Vmware Tanzu Platform - SM

Issue/Introduction

When uninstalling a Decoupled Stack tile from VMware Tanzu Application Service (TAS), the system may retain the updated cflinuxfs4 rootfs instead of reverting to the original version bundled with the TAS foundation. This results in the environment continuing to use the newer stack version despite the tile being uninstalled.

After upgrading a foundation with the Decoupled Stack tile and subsequently performing an uninstall, the Diego cells continue to report the updated cflinuxfs4 stack version (e.g., 1.344.0) instead of reverting to the foundation’s default version (e.g., 1.302.0).

The issue is primarily due to the rootfs remaining on the Diego cells; the uninstallation process does not automatically trigger a cleanup of these files from the cell storage.

Cause

The current architecture does not provide a native mechanism to run cleanup tasks for rootfs during the tile deletion process. Because the Diego cells do not automatically refresh the rootfs upon tile uninstallation, the cells continue to utilize the existing rootfs directory even after the runtime configuration is removed.

Resolution

To restore the foundation to its previous cflinuxfs4 stack version, perform a BOSH recreate of the Diego Cells.

1. Ensure Tile Uninstallation is Complete: Confirm the Decoupled Stack tile has been removed or unregistered from your Ops Manager configuration.
2. Recreate Diego Cells: Run the following BOSH command to recreate the Diego Cell instances:

   bash
   
   for i in `bosh -d <elastic_application_runtime_deployment> vms | grep diego_cell | awk '{print $1}' `
   do
   bosh -d <elastic_application_runtime_deployment> recreate $i --no-converge
   done
   

   Note: This operation will restart the cells and force them to re-provision the correct, default cflinuxfs4 stack version.

3.  Verify Stack Version: Once the recreation is complete, verify that the cflinuxfs4 version has been reverted to the expected default for your TAS foundation version:

   cf stacks

Additional Information

Future Considerations

Engineering (Reference: Jira TNZ-125345) is currently investigating the feasibility of adding a drain script to the runtime configuration BOSH release. This would potentially automate the cleanup of the rootfs during the uninstallation/deletion process, removing the need for manual BOSH recreates in the future.

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