I have worked with a certain php and mysql based crm application for a while as a developer and know it inside out. I have an idea to offer an on-demand saas based hosted version where the client and can purchase a plan based on the number of users. They will simply click a button and this will automatically spin up and deploy a brand knew instance of the application for them and they will then be able to log in and use the software but wont have any access to the actual web space apart the ability to download a dump of there data anytime they want. It will automatically assign a sub-domain and email them their login details when its ready. I basically want it to be as autonomous as possible.
I think I have three possible ways to go about this:
We’ll use digital ocean as an example provider
- I could have one or multiple VM’s or droplets and set up each user’s software in a different virtualhost - this way I can host multiple instances of the software on each droplet lowering costs.
- Create a new droplet for each user - this provides additional flexibility and is easier to configure but is a bit more costly.
- Use Docker and some sort of scalable cloud hosting and set up each users software in a different container.
Obviously by posting here I am looking at number 3 but realistically is this a viable option?
The way I understand it is I would use a docker container to hold the application code itself, Apache and php. I would then have a separate container to run mysql and hold all the databases. Then every time a customer signs up I would spin up another application container and create a new database in the mysql container. I also have separate container holding nginx to act as load balancer between all different containers. If my node/droplet started to struggle I could then just scale up using the cloud hosting to cope.
Does this sound right so far?
The application itself is customizationable and users could install modules and change layouts that would change the structure of the applications files. So I would need to be able to maintain this between container restarts as well as maintain their databases long term. I understand that we use volumes for this? but is putting the entire php file structure of the application into a volume on each container viable?
I would also need a way to upgrade application on mass as new version come out obviously the customers would need to be kept up to date.
Does all this sound feasible with docker?