Prerequisites

OpenJDK 8 JRE

Install openjdk8-jre from the community repository.

Edit /etc/apk/respositories and uncomment the appropriate community repository for your Alpine version:

Update the package cache.

apk update

Install the package.

apk add openjdk8-jre

Install MongoDB

apk add mongodb

Install s6

apk add s6

Create the unifi user and group.

adduser -D -H /srv/unifi -g unifi unifi

Change to the parent folder within which you wish to install the UniFi Controller.

cd /srv

Download the generic unix archive of the VERSION you wish to install.

Unpack the archive.

unzip UniFi.unix.zip

Rename the unpacked directory.

mv UniFi unifi

Change ownership.

chown unifi:unifi unifi

Lock down permissions.

chmod o-rwx unifi