As an OpenShift user, I want to know what OS/architectures an image stream tag supports, so that I can make an informed choice when choosing which tag to use.

ACCEPTANCE CRITERIA

• The image stream status tags' items (which is basically a history of updates to each tag in that image stream) should show the available OS/architecture available for the image in question
• When an image stream is updated with a new version of tag and that tag supports a different set of OS/architectures, the image stream status should reflect that
• Listing the supported architectures should be enabled by default. Due to object size constraints in etcd, customers should be able to opt-out of this feature by specifying an annotation on the image stream metadata (something like "image.openshift.io/hide-supported-platforms: true")

DOCUMENTATION

• The API change documentation is written by engineering in Go code.
• The introduced annotation to hide the platform list in the image stream status needs to be documented.

OPEN QUESTIONS

• Should each tag item in the status (`.status.tags[].items`) contain all the available platforms imported for that entry? This could blow things up a bit depending on how many platforms an image support, and how many entries we're keeping in the status.
  • See comments for discussion. The acceptance criteria for this task was updated to accommodate etcd object size constraints.