diff --git a/build-helpers/make-linux-build-docker-inner.sh b/build-helpers/make-linux-build-docker-inner.sh
index db79c8a6f5ba2f3593394acb5e861acad727e7de..77ea14e5aecb7259d5a9df5e55c421296e854835 100755
--- a/build-helpers/make-linux-build-docker-inner.sh
+++ b/build-helpers/make-linux-build-docker-inner.sh
@@ -8,7 +8,7 @@ cd /tmp/build
 
 useradd -d /home/user -m -s /bin/bash user
 
-yum install centos-release-SCL
+yum install -y centos-release-SCL
 yum install -y git python27 python27-python-devel tar gcc gcc-c++ mercurial numpy libffi-devel
 
 PYTHON_EXE=python2.7