-puppet module install puppetlabs-firewall
-puppet module install puppetlabs-stdlib
-puppet module install puppetlabs-apt
-puppet module install puppetlabs-postgresql
-puppet module install puppetlabs-mysql
+# In version 4.19 and 4.20, the "file_line" is not able to remove "search" and "domain" lines from the container's resolv.conf.
+# Since Puppet 4 does not support "union ranges" of versions (only Puppet 5 does, which is currently not included in Debian), require >=4.21.0 and ignore that <=4.18 works as well.
+# <5 is required for puppetlabs-postgresql v4: https://forge.puppet.com/puppetlabs/postgresql/4.9.0/dependencies
+# installing a newer stdlib causes postgresql-v4 fail installation.
+puppet module install puppetlabs-stdlib --version ">=4.21.0 <5.0.0"
+puppet module install puppetlabs-firewall --version 1
+puppet module install puppetlabs-apt --version 2
+puppet module install puppetlabs-postgresql --version 4
+puppet module install puppetlabs-mysql --version 3