This lesson's interactive features are locked, please to keep using them
Minikube vs. Prod
Minikube is a great tool for learning Kubernetes, but it's not a production-scale Kubernetes cluster. The primary difference is that Minikube runs a single-node cluster (by default), whereas production clusters are multi-node distributed systems.
Distributed Systems Are Complex
Whenever you're dealing with a system that involves multiple machines talking to each other over a network, you're dealing with a distributed system. Distributed systems are inherently complex, and Kubernetes is no exception, but that complexity is generally abstracted away from you as a K8s user. That's what makes Kubernetes so cool! It does a lot of the hard work for you.
Resources and Nodes
To zoom way out, Kubernetes' job is to run software applications, and applications require resources. Resources are things like:
- CPU
- Memory
- Disk space
Kubernetes' job is to manage those resources and allocate them to the applications that are running on it. Let's look at an oversimplified example:
3 Nodes (Machines)
| Node | RAM |
|---|---|
| Node 1 | 16GB |
| Node 2 | 8GB |
| Node 3 | 8GB |
5 Pods (Applications)
| App | Required RAM |
|---|---|
| App 1 | 12GB |
| App 2 | 2GB |
| App 3 | 5GB |
| App 4 | 4GB |
| App 5 | 4GB |
Kubernetes looks at the resources required by each application and decides which node to run it on. In this case, it might do something like this:
| Node | Apps | RAM Left Over |
|---|---|---|
| Node 1 | App 1 (12GB), App 2 (2GB) | 2GB |
| Node 2 | App 4 (4GB), App 5 (4GB) | 0GB |
| Node 3 | App 3 (5GB) | 3GB |
What happens if we get a new application that requires 10GB of RAM? The cluster doesn't have enough resources to run it! The solution? Easy. Just add another node to the cluster and let Kubernetes figure out where to run it.
This Won't Work With Minikube
With Minikube, you only get one node! So once your machine runs out of resources, you're out of luck. That's why Minikube is great for learning, but not for production.
There are Kubernetes clusters running in production that have thousands of nodes. That's a lot of resources to manage! But that's the beauty of Kubernetes.
If you're interested, you can find some case studies here. I liked this one from Bloomberg that shows they run hundreds of clusters with thousands of nodes each.