diff --git a/docker/docker-puppet.py b/docker/docker-puppet.py
index 373615b359..7e1d44edf0 100755
--- a/docker/docker-puppet.py
+++ b/docker/docker-puppet.py
@@ -230,6 +230,8 @@ with open(sh_script, 'w') as script_file:
     # $::deployment_type in puppet-tripleo
     export FACTER_deployment_type=containers
     export FACTER_uuid=$(cat /sys/class/dmi/id/product_uuid | tr '[:upper:]' '[:lower:]')
+    : ${LANG=en_US.UTF-8}
+    export LANG
     FACTER_hostname=$HOSTNAME /usr/bin/puppet apply --summarize \
     --detailed-exitcodes --color=false --logdest syslog --logdest console --modulepath=/etc/puppet/modules:/usr/share/openstack-puppet/modules $TAGS /etc/config.pp
     rc=$?