diff --git a/tools/gce_setup/grpc_docker.sh b/tools/gce_setup/grpc_docker.sh
index a73d3fd0808573b47bb16b0ce71354a0d4052e7a..3a37b2f00b97c9bf54e37239f81586e573795096 100755
--- a/tools/gce_setup/grpc_docker.sh
+++ b/tools/gce_setup/grpc_docker.sh
@@ -739,7 +739,7 @@ grpc_cloud_prod_gen_ruby_cmd() {
   local test_script+=" --use_tls-true"
   local gfe_flags=" --server_port=443 --server_host=grpc-test.sandbox.google.com --server_host_override=grpc-test.sandbox.google.com"
   local env_prefix="SSL_CERT_FILE=/cacerts/roots.pem"
-  local the_cmd="$cmd_prefix 'ruby $test_script $@'"
+  local the_cmd="$cmd_prefix '$env_prefix ruby $test_script $gfe_flags $@'"
   echo $the_cmd
 }