diff --git a/vertical-pod-autoscaler/hack/generate-api-docs.sh b/vertical-pod-autoscaler/hack/generate-api-docs.sh
index bb97ba661429..9168449c29ee 100755
--- a/vertical-pod-autoscaler/hack/generate-api-docs.sh
+++ b/vertical-pod-autoscaler/hack/generate-api-docs.sh
@@ -31,15 +31,15 @@ trap cleanup EXIT
 if [[ -z $(which crd-ref-docs) ]]; then
     (
         cd $WORKSPACE
-	      go install github.com/elastic/crd-ref-docs@latest
+        go install github.com/elastic/crd-ref-docs@latest
     )
-    CONTROLLER_GEN=${GOBIN:-$(go env GOPATH)/bin}/crd-ref-docs
+    export CONTROLLER_GEN=${GOBIN:-$(go env GOPATH)/bin}/crd-ref-docs
 else
-    CONTROLLER_GEN=$(which crd-ref-docs)
+    export CONTROLLER_GEN=$(which crd-ref-docs)
 fi
 
 cd "$(dirname "${BASH_SOURCE[0]}")/.."
-crd-ref-docs \
+$CONTROLLER_GEN \
     --source-path=pkg/apis/ \
     --config=./hack/api-docs/config.yaml \
     --renderer=markdown \