diff --git a/run_tests.sh b/run_tests.sh
index d0ea20a8d..5e9b18a51 100755
--- a/run_tests.sh
+++ b/run_tests.sh
@@ -256,7 +256,7 @@ if [ "${INSTALL_FROM_SOURCE}" = true ]; then
   export GEM_BIN_DIR=/tmp/packstackgems/bin/
   export PUPPETFILE_DIR=/usr/share/openstack-puppet/modules
   export GEM_HOME=/tmp/packstackgems
-  $SUDO gem install r10k --no-ri --no-rdoc
+  $SUDO gem install r10k -v 2.6.4 --no-ri --no-rdoc
   # make sure there is no puppet module pre-installed
   $SUDO rm -rf "${PUPPETFILE_DIR:?}/"*
   install_modules