GC kubemark image after cluster starts up

cluster/gce/util.sh

@@ -3130,3 +3130,8 @@ function ssh-to-node() {
 function prepare-e2e() {
   detect-project
 }
+
+# Delete the image given by $1.
+function delete-image() {
+  gcloud container images delete --quiet "$1"
+}

cluster/kubemark/gce/config-default.sh

@@ -39,6 +39,7 @@ MASTER_OS_DISTRIBUTION=${KUBE_MASTER_OS_DISTRIBUTION:-gci}
 NODE_OS_DISTRIBUTION=${KUBE_NODE_OS_DISTRIBUTION:-gci}
 MASTER_IMAGE=${KUBE_GCE_MASTER_IMAGE:-cos-stable-65-10323-64-0}
 MASTER_IMAGE_PROJECT=${KUBE_GCE_MASTER_PROJECT:-cos-cloud}
+CLEANUP_KUBEMARK_IMAGE=${CLEANUP_KUBEMARK_IMAGE:-true}
 
 # GPUs supported in GCE do not have compatible drivers in Debian 7.
 if [[ "${NODE_OS_DISTRIBUTION}" == "debian" ]]; then

test/kubemark/start-kubemark.sh

@@ -220,6 +220,14 @@ function create-and-upload-hollow-node-image {
     cd $CURR_DIR
   fi
   echo "Created and uploaded the kubemark hollow-node image to docker registry."
+  # Cleanup the kubemark image after the script exits.
+  if [[ "${CLEANUP_KUBEMARK_IMAGE:-}" == "true" ]]; then
+    trap delete-kubemark-image EXIT
+  fi
+}
+
+function delete-kubemark-image {
+  delete-image "${KUBEMARK_IMAGE_REGISTRY}/kubemark:${KUBEMARK_IMAGE_TAG}"
 }
 
 # Generate secret and configMap for the hollow-node pods to work, prepare