https://www.getpantheon.com/ is a hosting service which makes it easy to host your personal fluxkraft.
Running it in your sandbox is free, the only thing you have to take care of is that the cron runs regularely (more about this later).
Set up your site
To get started create your account on getpantheon and add a new site.
As Start State choose "Import manually".
For importing the code you can reference the latest fluxkraft tar file on github (see https://github.com/drunomics/fluxkraft_distro/releases) or upload it.
We don't need a database archive as we start from scratch.
But we need to upload some files: For this download the latest fluxkraft release on github, package the files folder ( /sites/default/files) as a .tar.gz file and upload it as files archive.
After importing go to your pantheon dashboard.
When everything is fine you can already click on "Visit development site" and run the installer.
Note: If you get composer manager requirements errors go sure that the files composer.json and composer.lock are present in /sites/default/files/composer. You can log in using sftp. In my case the file upload placed these files directly in the files folder.
Note: If you get a notice that your settings.php is not protected add a blank settings.php file in your /sites/default folder. More about this here.
As stated here Pantheon runs cron every hour. But if the site has not been accessed through the web by a visitor for at least two hours, the platform suspends the associated services until it's accessed again and cron will not run.
Tip: Configure pingdom in such a way that it directly calls your fluxkraft cron.php. You'll find the url for calling your fuxkraft cron.php from outside on your status report page: yourfluxkraft.org/admin/reports/status.