CiviCRM can now be installed on Drupal 8 on any hosting account with CiviHosting. All the install needs is composer and we have that installed globally on all servers. The official instructions are here:
https://docs.civicrm.org/installation/en/latest/drupal8/
Below is our original post on this subject, before there was an officially working installer, but all of the below is now outdated and irrelevant.
CiviCRM for Drupal 8 can only be installed on one of our WebApps accounts. Sometimes some of the steps below fail due to memory limits. If that happens to you, just contact our Support Team and they can raise your memory limit.
Here is how to install CiviCRM for Drupal 8:
1. Via the WebApps section of your hosting Control Panel, create an App called nodeapp in a subdomain different from the one where Drupal needs to be installed. Use “Node.js” and “LTS” for the “engine” and the rest of the settings leave as default.
2. Log in to the app via the command line running
sureapp project shell nodeapp
3. Install bower running
npm install -g bower
4. Logout of the “sureapp project shell” and create a Drupal installation in the ~/www/www/drupal8 directory running
php7.cli ~/private/composer.phar create-project roundearth/drupal-civicrm-project:8.x-dev ~/www/www/drupal8 --no-interaction
5. You will now need to complete the Drupal installation by accessing the installation wizard via your browser
6. Enable CiviCRM via the “Extend” page of Drupal
For upgrades, see Upgrading CiviCRM under Drupal 8: How can I get around this error? for one issue and how to fix it.