diff --git a/cluster/gce/util.sh b/cluster/gce/util.sh
index 6d75eb633b..0fc3f7cfe5 100755
--- a/cluster/gce/util.sh
+++ b/cluster/gce/util.sh
@@ -876,7 +876,7 @@ ENABLE_CACHE_MUTATION_DETECTOR: $(yaml-quote ${ENABLE_CACHE_MUTATION_DETECTOR:-f
 ENABLE_PATCH_CONVERSION_DETECTOR: $(yaml-quote ${ENABLE_PATCH_CONVERSION_DETECTOR:-false})
 ADVANCED_AUDIT_POLICY: $(yaml-quote ${ADVANCED_AUDIT_POLICY:-})
 ADVANCED_AUDIT_BACKEND: $(yaml-quote ${ADVANCED_AUDIT_BACKEND:-log})
-ADVANCED_AUDIT_TRUNCATING_BACKEND: $(yaml-quote ${ADVANCED_AUDIT_TRUNCATING_BACKEND:-})
+ADVANCED_AUDIT_TRUNCATING_BACKEND: $(yaml-quote ${ADVANCED_AUDIT_TRUNCATING_BACKEND:-true})
 ADVANCED_AUDIT_LOG_MODE: $(yaml-quote ${ADVANCED_AUDIT_LOG_MODE:-})
 ADVANCED_AUDIT_LOG_BUFFER_SIZE: $(yaml-quote ${ADVANCED_AUDIT_LOG_BUFFER_SIZE:-})
 ADVANCED_AUDIT_LOG_MAX_BATCH_SIZE: $(yaml-quote ${ADVANCED_AUDIT_LOG_MAX_BATCH_SIZE:-})