root@bootstrap:~# wget https://apt.puppet.com/puppet5-release-xenial.deb
root@bootstrap:~# dpkg -i puppet5-release-xenial.deb
root@bootstrap:~# apt-get update
...
Get:5 http://apt.puppetlabs.com xenial InRelease
Get:6 http://apt.puppetlabs.com xenial Release [76.0 kB]
Get:7 http://apt.puppetlabs.com xenial Release.gpg [836 B]
Get:8 http://apt.puppetlabs.com xenial/puppet5 amd64 Packages [6,884 B]
Get:9 http://apt.puppetlabs.com xenial/puppet5 i386 Packages [6,068 B]
Get:10 http://apt.puppetlabs.com xenial/puppet5 all Packages [3,521 B]
Fetched 93.3 kB in 0s (108 kB/s)
Reading package lists... Done
root@bootstrap:~# apt-get install puppetserver | 