diff --git a/tools/Dockerfile.ci b/tools/Dockerfile.ci
index fc52733bb214af918af34069e71b05b2eaa8511e..92aee9e777387374397682b3a22dafe1294ccde4 100644
--- a/tools/Dockerfile.ci
+++ b/tools/Dockerfile.ci
@@ -48,3 +48,5 @@ RUN yum -y update >/dev/null \
 RUN yum install -y java \
     && wget http://repos.fedorapeople.org/repos/dchen/apache-maven/epel-apache-maven.repo -O /etc/yum.repos.d/epel-apache-maven.repo \
     && yum install -y apache-maven
+
+RUN yum install -y lsof
diff --git a/tools/serving_build.sh b/tools/serving_build.sh
index 81099781773676e0844790e8d4ab79308faf2487..44a1d5e16b9be16d28b1274cb1a058248b062f24 100644
--- a/tools/serving_build.sh
+++ b/tools/serving_build.sh
@@ -628,7 +628,6 @@ function python_test_grpc_impl() {
             fi
             echo "grpc impl test success"
             kill_server_process
-            kill_process_by_port 9393
             ps -ef | grep "cube" | grep -v grep | awk '{print $2}' | xargs kill
 
             cd .. # pwd: /Serving/python/examples/grpc_impl_example