Tanzu Jammy Stack on AWS Lambda - Filesystem Limitations

Products

• VMware Tanzu Spring Essentials

Issue/Introduction

Tanzu Jammy(Ubuntu 22.04) stack images have SBOM files at /cnb/sbom: 4a9eb482.syft.json and 4a9eb482.cdx.json.

 

When deploying an application image built on this stack to AWS Lambda, the deployment fails with the following error:

`MissingParentDirectory: Parent directory does not exist for file: cnb/sbom/4a9eb482.syft.json`

Cause

The stack images create the files in the /cnb/sbom directory as part of the final layer tarball, without having created the directory /cnb in the previous lower layer.

This runs successfully with other OCI runtimes (Docker, Kubernetes, etc) which create the missing parent directories. AWS Lambda seems to have stricter filesystem limitations and uses a deterministic flattening process. More details here: https://arxiv.org/pdf/2305.13162

Resolution

AWS is unlikely to make any changes since this occurs during image construction. Jammy base stack v0.1.178 has been released with the fix.