diff --git a/cluster/kubemark/gce/config-default.sh b/cluster/kubemark/gce/config-default.sh
index 8fea98fcc08..c85e1672f72 100644
--- a/cluster/kubemark/gce/config-default.sh
+++ b/cluster/kubemark/gce/config-default.sh
@@ -24,6 +24,11 @@
 source "${KUBE_ROOT}/cluster/gce/config-common.sh"
 
 CLEANUP_KUBEMARK_IMAGE=${CLEANUP_KUBEMARK_IMAGE:-true}
+TEST_CLUSTER_LOG_LEVEL="${TEST_CLUSTER_LOG_LEVEL:-"--v=4"}"
+
+# If you want to set up multiple kubemark clusters with different "names",
+# you should change this env per each start-kubemark.sh invocation.
+KUBE_GCE_INSTANCE_PREFIX="${KUBE_GCE_INSTANCE_PREFIX:-"default"}"
 
 # NUM_NODES is used by start-kubemark.sh to determine a correct number of replicas.
 NUM_NODES=${KUBEMARK_NUM_NODES:-10}