Module Review: Kubernetes Foundations

Congratulations! You have completed the first module of the Kubernetes Course. Let’s review the core concepts.

1. Key Takeaways

Kubernetes is a Distributed System: It has a Control Plane (Brain) and Worker Nodes (Muscle).
API Server is the Hub: All components talk only to the API Server. It is the gatekeeper.
Etcd is the State: It is a consistent key-value store. If Etcd dies, the cluster dies.
Scheduler & Controllers: The Scheduler assigns Pods to Nodes. Controllers ensure the Desired State matches the Actual State.
Declarative Model: You tell Kubernetes what you want (Manifest), not how to do it.

Test your knowledge! Click on a card to flip it.

What is the only component that talks to Etcd?

The API Server (kube-apiserver).

Which component runs on every worker node and manages containers?

The Kubelet.

What consensus algorithm does Etcd use?

Raft.

Imperative vs Declarative: Which one does Kubernetes use?

Declarative (You define the Desired State).

What is the role of Kube-proxy?

It maintains network rules on nodes to implement Services (routing traffic to Pods).

What happens if the Scheduler goes down?

New Pods will be created in Etcd (Pending state) but will never be assigned to a Node.

Component	Type	Role	Key Trait
API Server	Control Plane	The Hub / Front Desk	Only component to talk to Etcd.
Etcd	Control Plane	The Brain / Memory	Distributed Key-Value Store. Raft Consensus.
Scheduler	Control Plane	The Matchmaker	Assigns Pods to Nodes based on resources/constraints.
Controller Mgr	Control Plane	The Fixer	Runs loops to reconcile state (Node, ReplicaSet).
Kubelet	Worker Node	The Captain / Agent	Registers node, starts pods, reports status.
Kube-proxy	Worker Node	The Network Switch	Manages iptables/IPVS for Services.
Container Runtime	Worker Node	The Engine	Runs the actual containers (containerd/CRI-O).

You have a solid foundation. Now it’s time to build something.

Or verify your definitions in the Kubernetes Glossary.