Hostman allows you to scale your applications out of the box. Click on Scaling in the menu at left to scale your service. You'll see something like this.
(If you've never scaled your service before, you'll see only one node and its current load average.) If you see the load average enter the critical zone at a peak time, you can scale it by clicking "+".
Each back-end application can be easily scaled. You don't have to change the IP address or use a load balancer. We use load balancers all the time, and when you need to scale you can do so in one click.
Preparing your application for scaling
The only thing you need to prepare is your persistent data. Make sure that you store all the data in the database and nothing in local storage, because you won't be able to access this data from another instance.
If you need persistent storage with the file system, you can use something like GridFS. This is a layer that allows you to use MongoDB like a filesystem.