diff --git a/flink-jepsen/docker/up.sh b/flink-jepsen/docker/up.sh
index 5479b3b5948b7..d3fbf0505ed62 100755
--- a/flink-jepsen/docker/up.sh
+++ b/flink-jepsen/docker/up.sh
@@ -23,7 +23,7 @@ dockerdir=$(dirname $0)
 dockerdir=$(cd ${dockerdir}; pwd)
 
 if [ ! -f ./id_rsa ]; then
-    ssh-keygen -t rsa -N "" -f ./id_rsa
+    ssh-keygen -m PEM -t rsa -N "" -f ./id_rsa
 fi
 
 export JEPSEN_ROOT=${dockerdir}/../