What is the purpose of an ImageStreamTag, and how does a deployment react to updates to the tag?

• A. It stores secret data for reuse.
• B. It represents a version; a deployment with an imageChange trigger will redeploy when the tag updates.
• C. It defines route hostnames for external access.
• D. It is a build artifact from a Jenkins pipeline.

Answer: (B)

ImageStreamTag is a versioned reference to an image inside an ImageStream. It acts as a pointer that tracks a specific image tag, which deployments can watch for changes. When a deployment is configured with an imageChange trigger for that tag, updating the tag (pushing a new image with the same tag) automatically starts a new rollout of the deployment using that updated image. The pod template in the deployment references the ImageStreamTag, so the deployment controller detects the tag change and replaces pods with the new image in a rolling update. If there’s no imageChange trigger, updating the tag won’t cause an automatic redeploy; you’d need to trigger the rollout by another mechanism.