Pi-hole install script and dhcpcd.conf

[deHakkelaar]

@Roo

For whatever reason, when you issue sudo on Ubuntu, it does a name lookup. With the way that pi-hole goes and whacks the DNS when it configures a static IP for you - it breaks the ability to look up the /etc/hostname name. That's messed up

That is an issue with sudo and not Pi-hole.
If setup a Linux host properly without Pi-hole, your suppose to provide the own hostname in both the /etc/hostname & /etc/hosts files anyway like you did.
That would have probably fixed your sudo issue.
The /etc/hosts file has precedence over DNS name resolution meaning a ping, curl or netcat will first look at the hosts file before forwarding an A or AAAA query to a DNS server.

@Roo

which is why I hacked /etc/hosts to fix it for my configuration

Thats not hacking, thats the only proper way or a variant of it (I use 127.0.1.1 to the same effect):

pi@ph5b:~ $ cat /etc/hosts
127.0.0.1       localhost
::1             localhost ip6-localhost ip6-loopback
ff02::1         ip6-allnodes
ff02::2         ip6-allrouters

127.0.1.1       ph5b.home.dehakkelaar.nl  ph5b