diff --git a/.gitlab-ci.yml b/.gitlab-ci.yml
index e2956f7851f543dfa055197accc1744b1890b762..a1ef56940d1ce50bf3e2b967a31adc883ef3e788 100644
--- a/.gitlab-ci.yml
+++ b/.gitlab-ci.yml
@@ -206,10 +206,10 @@ deploy_http_proxy_node:
       export cmd="openstack server create"
       cmd+=" -c id -f value --image $HTTP_PROXY_IMAGE_ID"
       cmd+=" --flavor $INSTANCE_FLAVOR"
-      cmd+=" --network $PROXY_NETWORK"
       cmd+=" --security-group webserver_sec_group"
       cmd+=" --security-group allow-ssh"
       cmd+=" --user-data user_data.txt"
+      if [ -n "$PROXY_NETWORK" ];then cmd+=" --network $PROXY_NETWORK" fi
       if [ -n "$HTTP_PROXY_PORT" ];then cmd+=" --port $HTTP_PROXY_PORT"; fi
       cmd+=" --wait $HTTP_PROXY_INSTANCE_NAME"
     - export HTTP_PROXY_INSTANCE_ID=$(bash -c "$cmd")
@@ -257,9 +257,9 @@ deploy_ssh_proxy_node:
       export cmd="openstack server create"
       cmd+=" -c id -f value --image $SSH_PROXY_IMAGE_ID"
       cmd+=" --flavor $INSTANCE_FLAVOR"
-      cmd+=" --network $PROXY_NETWORK"
       cmd+=" --security-group allow-ssh"
       cmd+=" --user-data user_data.txt"
+      if [ -n "$PROXY_NETWORK" ];then cmd+=" --network $PROXY_NETWORK" fi
       if [ -n "$SSH_PROXY_PORT" ];then cmd+=" --port $SSH_PROXY_PORT"; fi
       cmd+=" --wait $SSH_PROXY_INSTANCE_NAME"
     - export SSH_PROXY_INSTANCE_ID=$(bash -c "$cmd")
@@ -308,9 +308,9 @@ deploy_login_node:
       export cmd="openstack server create"
       cmd+=" -c id -f value --image $LOGIN_IMAGE_ID"
       cmd+=" --flavor $INSTANCE_FLAVOR"
-      cmd+=" --network $INSTANCE_NETWORK"
       cmd+=" --security-group allow-ssh"
       cmd+=" --user-data user_data.txt"
+      if [ -n "$INSTANCE_NETWORK" ];then cmd+=" --network $INSTANCE_NETWORK" fi
       if [ -n "$LOGIN_PORT" ];then cmd+=" --port $LOGIN_PORT"; fi
       cmd+=" --wait $LOGIN_INSTANCE_NAME"
     - export LOGIN_INSTANCE_ID=$(bash -c "$cmd")