What you will learn
- A cluster is a group of machines and control components used to run workloads.
- A node provides compute capacity; a Pod is the smallest deployable workload unit.
- kubectl reads a kubeconfig context to find the target cluster.
Understand clusters control plane and nodes
Kubernetes schedules and manages containerized applications across a cluster. The cluster includes control-plane components that track what you want and worker nodes that run workloads. You normally describe the desired state in YAML and let the controllers work toward it. For your first exercise, use a local training cluster, not a production environment. Begin by checking which cluster your command-line tool is targeting. Then inspect the namespaces and create a Deployment manifest without applying it. That dry-run step is a safe introduction to Kubernetes declarations because it shows exactly what would be submitted.
- A cluster is a group of machines and control components used to run workloads.
- A node provides compute capacity; a Pod is the smallest deployable workload unit.
- kubectl reads a kubeconfig context to find the target cluster.
- A Deployment manages the desired number of matching Pods.
- --dry-run=client produces a resource description without creating the object.
Words you need
A
A cluster is a group of machines and control components used to run workloads.
A
A node provides compute capacity; a Pod is the smallest deployable workload unit.
kubectl
kubectl reads a kubeconfig context to find the target cluster.
A
A Deployment manages the desired number of matching Pods.
Examples
Confirm your selected cluster
kubectl config current-contextkind-etg-lab
Explanation: The output is the current context name. Use your actual lab context and never assume the selection is safe.
Inspect namespace boundaries
kubectl get namespacesNAME STATUS default Active kube-system Active
Explanation: The list varies by cluster. Namespace boundaries organize objects but do not replace RBAC or network policy.
Draft a Deployment without creating it
kubectl create deployment etg-web --image=nginx:alpine --dry-run=client -o yamlapiVersion: apps/v1 kind: Deployment metadata: ... spec: ...
Explanation: The command prints a Deployment specification. Review the YAML before applying it to a practice cluster.
Practical chapter project
Build and verify
Run a local cluster, record the current context, inspect namespaces, and save a dry-run Deployment YAML for review.
How to check the result
Record your actual starting state and the visible final result. If a service account is needed, confirm permission and cost protection first. Your project meets the target when someone else can repeat it safely and see the intended outcome.
Check your understanding
01 What is a Pod?
A group of one or more containers with shared Kubernetes scheduling and networking.
02 What does a Deployment manage?
Desired replica count and rolling updates for its Pods.
03 Why inspect the current context?
To avoid issuing commands against the wrong cluster.
04 What does client dry-run do?
Builds and displays a resource definition without sending a creation request to the cluster.
Summary
A cluster is a group of machines and control components used to run workloads. A node provides compute capacity; a Pod is the smallest deployable workload unit. Complete the chapter project before opening Chapter 2.