Create scalable onsite private cloud infrastructure

We are looking to create our own private onsite hybrid cloud infrastructure that we can scale out demand as required to independent cloud service providers as we need. Currently we have 4x physical servers (mixed installs, can be wiped) plus 2x Synology NAS boxes running web dav/CIFS (for remote users doing projects with PC file, folder and webpage access via synology active directory server and webpage authentication) with our other main goal of hosting a scalable drupal based website which also is able to allow remote developers full SSH access without compromising user projects and clients files (VM's or containers?) ## Some main goals we would like out of this, along with a few technologies we are familiar with (open to latest technologies or better alternatives): - Private cloud setup (Cockpit, MaaS, OpenStack/Cloud foundry) and administration with central control over servers. We want to be able to monitor, install and update servers centrally so we can expand and add new physical/virtual servers easily. - Drupal stack. We would like container orchestration to be automatic with overflow for demand sent to public cloud (Juju, Kubernetes, Docker, Wodby) We would like a stack with production/development options...currently we are using a container stack in docker using the Wodby setup. - MariaDB cluster/Galera, Maxscale, Clustercontrol central administration and setup for replicated, distributed and scalable database - File storage system for replicated, distributed and scalable data storage (GlusterFS?). Administration centrally for users.