Which command configures the build config phpbuild to trigger whenever the base image newapp/php:1 changes?

• A. oc set trigger bc/phpbuild --from-image=newapp/php:1
• B. oc set trigger bc/phpbuild --from-image=newapp/php:2
• C. oc set triggers bc/phpbuild --from-image=newapp/php:1
• D. oc set trigger bc/phpbuild --from-image=newapp/php:0

Answer: (A)

OpenShift builds can automatically start when the image they rely on changes. This is done by configuring an ImageChange trigger on the BuildConfig, specifying which image stream and tag to watch. The correct command targets the BuildConfig by name and attaches a trigger that watches the image newapp/php:1. When that image tag updates (a new image is pushed for that tag), a new build for phpbuild will be triggered automatically. The other options would either watch a different tag (which wouldn’t respond to changes to tag 1) or use a variant of the command that doesn’t apply the same trigger in this context.