I use analogy whenever I need to explain something in the clearest and fastest possible way. Gaining knowledge in an abstract manner is hard and costly. Using existing knowledge as a foundation speeds up the learning process and prevents misunderstandings. When a C# developer, for instance, asks me what’s
flatMap in Scala, I’ll ask if they know what’s
SelectMany? If they do, explaining how
flatMap works on non-list types would be far faster and easier.
Now let’s do this with Kubernetes and AWS. Let’s see what are the Kubernetes components closest equivalents in AWS.
The point is that an analogy doesn’t provide a deep understanding of a new concept, but it provides the foundation to speed up the learning process. So don’t expect a conclusive 1:1 mapping from Kubernetes elements to AWS.
AWS equivalent: EC2
Nodes in K8s are basically machines, either virtual or physical.
A Pod is simply the smallest compute unit in Kubernetes. Think of a Docker container.
A Deployment object describes the desired state for Pods and ReplicaSets. As an example, you can specify a docker image and the number of replicas you want to be run within your cluster in a Deployment object and apply it. Kubernetes will take care of the rest.
A Serivce sits in front of the Pods and route the traffic to them. Service in k8s is far more abstract and capable than anything available in AWS at the moment. It can also utilize AWS (or other clouds) load balancers to expose the applications.
AWS equivalent: ELB
Volume in k8s is very similar to Docker volumes in terms of interface but it’s more abstract. For example, you can use AWS EBS as a volume back-end in k8s.
AWS equivalent: VPC
K8s allows defining multiple virtual clusters backed by the same physical cluster using Namespaces.
There are two paths we can map the Kubernetes components to AWS ones through:
- EC2: Each VM runs an instance of the application
- ECS: Runs the applications as Docker containers and distribute the load among EC2 instances in the cluster
|K8s component||AWS (EC2 Path)||AWS (ECS Path)|
|Deployment||Auto scaling group||Task Definition|
|Service||Load balancer||Load balancer|