Export MINION_SIZE as MACHINE_TYPE for gke tests

hack/jenkins/e2e.sh

@@ -701,6 +701,8 @@ case ${JOB_NAME} in
     : ${PROJECT:="k8s-jkns-e2e-gke-1-1-features"}
     : ${FAIL_ON_GCP_RESOURCE_LEAK:="true"}
     : ${GINKGO_TEST_ARGS:="--ginkgo.focus=GCE\sL7\sLoadBalancer\sController|Job|Horizontal\spod\sautoscaling"}
+    # At least n1-standard-2 nodes are required for the cluster to
+    # have enough cpu/ram to run the Horizontal pod autoscaling tests.
     MINION_SIZE="n1-standard-2"
     ;;
 
@@ -1360,6 +1362,7 @@ export KUBE_GKE_NETWORK=${E2E_NETWORK}
 export E2E_SET_CLUSTER_API_VERSION=${E2E_SET_CLUSTER_API_VERSION:-}
 export DOGFOOD_GCLOUD=${DOGFOOD_GCLOUD:-}
 export CMD_GROUP=${CMD_GROUP:-}
+export MACHINE_TYPE=${MINION_SIZE:-}  # GKE scripts use MACHINE_TYPE for the node vm size
 
 if [[ ! -z "${GKE_API_ENDPOINT:-}" ]]; then
   export CLOUDSDK_API_ENDPOINT_OVERRIDES_CONTAINER=${GKE_API_ENDPOINT}