Hey @gerbreown -
The number of applications that it is physically possible to run on a single Droplet is a function of:
- Droplet Size i.e. how much CPU, Memory, Storage and Network capacity does you Droplet have
- Resource demands of the applications. i.e. how much Memory (RAM), Storage, CPU and Network do the applications demand
There are some users who run hundreds or even thousands of applications or websites on a single Droplet, because either:
- They have a very large Droplet, or…
- Their application(s) take up a very low amount of resources, or in some cases one process on the Droplet is handling many applications.
But there are also some availability and reliability considerations that should go into the decision of how many applications should run on a single droplet.
- What if one application requires you to reboot the Droplet? If all your applications are on the same Droplet, they will go down as well.
- What if one application on the Droplet has a bug that starts using all available CPU or Memory? That could cause your other applications to go down.
For those reasons, devops developers who are focused on reliability often move towards using immutable infrastructure where different applications generally run on their own Droplet, or even multiple Droplets.
To go even further, sometimes different parts of an application are run on different Droplets. For example there are benefits to moving the database to a different Droplet, or just using Managed Databases.
But at the end of the day, if you are interested in starting small it is perfectly fine to run multiple applications on a single Droplet, you can just keep an eye on how much CPU, Memory and Storage you are using by watching the Monitoring dashboard.
This tutorial will demonstrate how to plan and set up a sample production application from start to finish. Hopefully, this will help you plan and implement your own production server environment, even if you are running a different application on a completely different technology stack. Because this tutorial covers many different system administration topics, it will often defer the detailed explanation to external supporting articles that provide supplemental information.