[SPARK-26704] docker-image-tool.sh should copy custom Dockerfiles into the build context for inclusion in images

• Type: Improvement
• Status: Resolved
• Priority: Major
• Resolution: Not A Problem
• Affects Version/s: 2.4.0
• Component/s: Kubernetes, Spark Core
• Assignee: Unassigned
• Reporter: Rob Vesse
• Created: 23/Jan/19 11:02
• Updated: 17/May/20 18:26
• Resolved: 23/Jan/19 19:31

Description

As surfaced in the discussion on the PR for SPARK-26687 (https://github.com/apache/spark/pull/23613) when using custom Dockerfiles these are not copied into the build context. Rather the build context includes the default Dockerfiles from Spark regardless of what Dockerfiles the end user actually used to build the images.

The suggestion in the PR was that the script should copy in the custom Dockerfiles over the stock Dockerfiles. This potentially aids in reproducing the images later because someone with an image can get the exact Dockerfile used to build that image.

A related issue is that the script allows for and even in some cases implicitly uses Docker build arguments as part of building the images. In the case where build arguments are used these should probably also be captured in the image to aid reproducibility.