18.04 - How to install ubuntu server for lxc on a smartphone (ARM or x86, bare metal)?

As of May 2019 what are the options (if any) to install Ubuntu server on a smartphone device?

I don't need much of the smartphone functionality, I don't need desktop and touchscreen blows and whistles at all (the phone will be accessed mostly through SSH and USB, it would be nice to have a working terminal on the phone).

I intend to use my old device (originally Android, Nexus 4 or BQ Aquaris E5 or ASUS ZenFone 2) as a mobile LAMP server and run lxc containers on it (serving the apps).

Does anybody have any experience / ideas?

I looked at Ubuntu Touch / UBports solution, but it focuses mostly on smartphone functionality (supporting all hardware, installing Android apps, nice touch desktop etc.). I need more of a server - less of a smartphone... Not only me, perhaps.

BTW the most detailed answers related to Ubuntu Touch (for those who are interested) are gathered here: What hardware does Ubuntu Touch support?

Links to related questions / discussions:

1. How to use Android SDK and smartphone vendor tools to boot another kernel?




2. Ubuntu Touch (UBports) and Android support for LXC/LXD containers (for running Ubuntu): current state