Custom Domains for the Multi-tenant Web Application

Question

I am developing an application (RoR + Heroku) that allows users to create their own websites either using my subdomain (pagename.myapp.com) or using my own domain (pagename.com). An important point of this is that this option is the key to my business: subdomains are free plans, and user domains are paid. Therefore, I have a table where I store the user domains of each user and check if this page is active (exists and paid a quota).

To do this, I need to give users the opportunity to point their domain to my servers. All we know is that Heroku does not recommend using DNS A-Records .

I would also like to distract this feature as much as possible in order to switch my infrastructure (Heroku to AWS) in the future without asking all my users to change their DNS zone. Taking this into account, I believe that the best option would be to start something like an EC2 proxy server (using AWS Elastic IP), which gives me the right to own this IP address. This proxy, I think, should redirect to proxy.myapp.com, and I would allow the request at the application level.

Due to the fact that I did not find clear information about this, I am not sure whether this hypothesis is the best solution and how to configure a proxy server (which type of proxy uses? Nginx is possible?).

Said that I would like to ask for recommendations / best practices to address this "common" function.

thanks

Answer 1

What you want to do is pretty simple to implement. Your assumptions are correct for proxy settings. Nginx or haproxy will work just fine for this (I would personally use haproxy). Here are some of the problems you will encounter:

• Changing the host header on the proxy server may cause the target web application to generate invalid links. You can use relative paths to fix this, but this requires the web application developer to be aware of the environment in which they work.

  • user connects to www.example.com (proxy server)
  • The proxy server connects to www.realdomain.com (web application).
  • The web application has a link for the shopping cart. www.realdomain.com/shoppingcart
  • the end user clicks on the link, but the link is www.realdomain.com/shoppingcart, not www.example.com/shoppingcart.

• The cost of the host acting as a proxy server. This can get out of hand very quickly. For example, do you want redundancy, if so, how do you plan to implement this? Are you planning to break ssl? If so, you will have to increase the number of CPUs to accommodate the extra load. Do you want to have a secure connection to the hero from your proxy? If you do this, you will also need to increase the number of processors. You may need to add an extra drum, depending on the number of simultaneous connections.

• Heroku also regularly changes its balance sheets. This is important because your proxy will need to reload the configuration / update the ip addresses of heroku instances every 60 seconds. In my experience, they can change once or twice a day, but the DNS record that they use has a 60 second TTL. This means that you must ensure that you can update the configuration to 60 seconds.

For almost a year now, my company has been doing something very similar to this. We use haproxy and just reload the configuration regularly. We have never had shutdowns or interrupts for our end users. Nginx is also a very good product. He built DNS caching, so if you go this route, you need to make sure that you configured it correctly so that the DNS TTL cache is 60 seconds.

Answer 2

Many of your customers will want to use your application on their domain top? For instance. example.com, not theapp.example.cpm? If not, I would recommend them to use CNAME for proxy.myapp.com, which CNAMEs for myapp.herokuapp.com. Then you can update proxy.myapp.com without interrupting the client.

If you need apex or record support, you need to configure Nginx as a reverse proxy for your Heroku application. Keep in mind that if you need HTTPS support for client domains, you will need to do some kind of certificate management on your proxy.