IHere’s what you need to do to run the Unifi Controller on Debian Buster:
Add the following to /etc/apt/sources.list:
deb http://repo.mongodb.org/apt/debian jessie/mongodb-org/3.4 main
Do:
wget -qO - https://www.mongodb.org/static/pgp/server-3.4.asc | apt-key add -
(thx u/theinvisibleman_ for the key update info on his post here)
Grab:
http://security.debian.org/debian-security/pool/updates/main/o/openssl/libssl1.0.0_1.0.1t-1+deb8u12_amd64.deb
http://security.debian.org/debian-security/pool/updates/main/o/openjdk-8/openjdk-8-jre-headless_8u232-b09-1~deb9u1_amd64.deb
Do:
dpkg -i <package deb file>
To install both of those packages. Then:
apt-get update
And install the mongodb packages:
apt-get install mongodb-org-server mongodb-org-tools mongodb-org-shell
This should give you all you need to install the controller deb.
If I missed any depends, let me know as I threw this together after the fact and may have forgotten something.