diff --git a/vagrant/puppet_master/install_certs.sh b/vagrant/puppet_master/install_certs.sh
index 285560b..68be1b4 100644
--- a/vagrant/puppet_master/install_certs.sh
+++ b/vagrant/puppet_master/install_certs.sh
@@ -1,10 +1,14 @@
-#!/bin/bash
+#!/usr/bin/env bash
+
+set -eu
 
 CERT_DIR="/tmp/puppet_master"
 PUPPET_CERT_DIR=/var/lib/puppet/ssl
 
 if [ ! -d ${PUPPET_CERT_DIR} ]; then
+  apt-get update
+  apt-get install -y postgresql
   mkdir -p ${PUPPET_CERT_DIR}/
   cp -r $CERT_DIR/* ${PUPPET_CERT_DIR}
   chown -R puppet:puppet ${PUPPET_CERT_DIR}
 fi