diff --git a/test/gke/release-cluster.sh b/test/gke/release-cluster.sh
index 067cbfdcfe09..cc76e931a55c 100755
--- a/test/gke/release-cluster.sh
+++ b/test/gke/release-cluster.sh
@@ -1,6 +1,16 @@
 #!/bin/bash
 
 export KUBECONFIG=gke-kubeconfig
+cluster=$(cat cluster-name)
+
+# Create a function to unlock the cluster. We then execute this on script exit.
+# This should occur even if the script is interrupted, by a jenkins timeout,
+# for example.
+unlock() {    
+    echo "releasing cluster lock from $cluster"
+    kubectl annotate deployment lock lock-
+}
+trap unlock EXIT
 
 # We leak istio pods for an unknown reason (these tests do cleanup). This may
 # be related to timeouts or other failures. In any case, we delete them here to
@@ -13,12 +23,8 @@ echo "deleting terminating namespaces"
 ./delete-terminating-namespaces.sh
 
 set -e
-
-cluster=$(cat cluster-name)
+    
 echo "scaling $cluster ng to 0"
 yes | gcloud container clusters resize $cluster --node-pool default-pool --num-nodes 0 --zone $GKE_ZONE
 
-echo "releasing cluster lock from $cluster"
-kubectl annotate deployment lock lock-
-
-rm cluster-name
+rm -f cluster-name