Kubernetes Quick Cheat Sheet

Here’s a comprehensive Kubernetes cheat sheet, covering essential commands, objects, and concepts:

Basic Kubernetes Concepts

Cluster: A set of machines (nodes) that run containerized applications.
Node: A single machine in the cluster (physical/virtual).
Pod: The smallest deployable unit in Kubernetes (one or more containers).
Service: Exposes a set of Pods as a network service.
Deployment: Manages replica sets and ensures desired state.
Namespace: Provides scope for resources in a cluster.

Kubernetes Command Basics

Command	Description
`kubectl version`	Show kubectl and cluster version
`kubectl cluster-info`	Display information about the cluster
`kubectl get nodes`	List nodes in the cluster
`kubectl get pods`	List pods in the default namespace
`kubectl get services`	List all services
`kubectl get deployments`	List all deployments
`kubectl get namespaces`	List all namespaces
`kubectl get events`	List events in the cluster
`kubectl config view`	Show kubectl config
`kubectl config current-context`	Show the current context

Viewing Resources

Command	Description
`kubectl get [resource]`	List specific resource type (e.g., pods, services, deployments)
`kubectl describe [resource] [name]`	Detailed description of a resource
`kubectl logs [pod-name]`	Get logs for a specific pod
`kubectl logs [pod-name] -c [container-name]`	Get logs for a specific container in a pod
`kubectl exec [pod-name] -- [command]`	Execute a command in a pod (like `docker exec`)

Creating and Managing Pods

Command	Description
`kubectl run [pod-name] --image=[image]`	Create a pod from an image
`kubectl delete pod [pod-name]`	Delete a pod
`kubectl scale deployment [name] --replicas=[n]`	Scale a deployment to `n` replicas
`kubectl expose pod [pod-name] --port=[port]`	Expose a pod as a service

Working with Deployments

Command	Description
`kubectl create deployment [name] --image=[image]`	Create a deployment
`kubectl rollout status deployment [name]`	Check the status of a deployment rollout
`kubectl rollout undo deployment [name]`	Undo a deployment rollout
`kubectl delete deployment [name]`	Delete a deployment

Services and Networking

Command	Description
`kubectl expose deployment [name] --type=[type] --port=[port]`	Expose a deployment as a service (types: ClusterIP, NodePort, LoadBalancer)
`kubectl get svc`	List all services
`kubectl describe svc [service-name]`	Get details of a service
`kubectl delete svc [service-name]`	Delete a service

Namespaces

Command	Description
`kubectl create namespace [name]`	Create a new namespace
`kubectl get namespaces`	List all namespaces
`kubectl config set-context --current --namespace=[name]`	Set current namespace
`kubectl delete namespace [name]`	Delete a namespace

ConfigMaps and Secrets

Command	Description
`kubectl create configmap [name] --from-literal=[key=value]`	Create a ConfigMap from literal values
`kubectl create configmap [name] --from-file=[file-path]`	Create a ConfigMap from a file
`kubectl get configmaps`	List ConfigMaps
`kubectl describe configmap [name]`	Show ConfigMap details
`kubectl delete configmap [name]`	Delete a ConfigMap

Command	Description
`kubectl create secret generic [name] --from-literal=[key=value]`	Create a Secret from literal values
`kubectl get secrets`	List Secrets
`kubectl describe secret [name]`	Show Secret details
`kubectl delete secret [name]`	Delete a Secret

Volumes and Storage

Command	Description
`kubectl create -f [persistent-volume-file].yaml`	Create a PersistentVolume from a YAML file
`kubectl get pv`	List all PersistentVolumes
`kubectl describe pv [pv-name]`	Show details of a PersistentVolume
`kubectl create -f [persistent-volume-claim].yaml`	Create a PersistentVolumeClaim
`kubectl get pvc`	List all PersistentVolumeClaims
`kubectl describe pvc [pvc-name]`	Show details of a PersistentVolumeClaim

Rolling Updates and Rollbacks

Command	Description
`kubectl rollout status deployment/[deployment-name]`	View status of a rolling update
`kubectl set image deployment/[name] [container-name]=[new-image]`	Update container image
`kubectl rollout history deployment/[deployment-name]`	View rollout history
`kubectl rollout undo deployment/[deployment-name]`	Rollback to the previous deployment

Scaling Applications

Command	Description
`kubectl scale deployment [name] --replicas=[n]`	Scale the number of replicas
`kubectl autoscale deployment [name] --min=[n] --max=[m] --cpu-percent=[percent]`	Autoscale a deployment based on CPU usage

Resource Quotas and Limits

Command	Description
`kubectl create -f [resource-quota].yaml`	Create a ResourceQuota
`kubectl get resourcequotas`	List ResourceQuotas
`kubectl describe resourcequota [name]`	Show details of a ResourceQuota
`kubectl delete resourcequota [name]`	Delete a ResourceQuota

Port Forwarding

Command	Description
`kubectl port-forward [pod-name] [local-port]:[remote-port]`	Forward local port to a pod’s port
`kubectl port-forward service/[service-name] [local-port]:[remote-port]`	Forward local port to a service port

Debugging

Command	Description
`kubectl describe pod [pod-name]`	Get details of a specific pod (useful for troubleshooting)
`kubectl logs [pod-name]`	View pod logs
`kubectl exec -it [pod-name] -- /bin/sh`	Execute a shell inside the pod
`kubectl get events`	Get a list of events in the cluster

YAML Essentials

Pod Definition Example

apiVersion: v1
kind: Pod
metadata:
  name: my-pod
  namespace: default
spec:
  containers:
  - name: my-container
    image: nginx
    ports:
    - containerPort: 80

Deployment Example

apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-deployment
spec:
  replicas: 3
  selector:
    matchLabels:
      app: my-app
  template:
    metadata:
      labels:
        app: my-app
    spec:
      containers:
      - name: my-container
        image: nginx
        ports:
        - containerPort: 80

Kubernetes Components

Component	Description
Kubelet	Agent that runs on nodes and ensures containers are running
Kube-Proxy	Manages network communication inside the cluster
etcd	Key-value store for cluster data
API Server	Frontend for the Kubernetes control plane
Controller Manager	Manages cluster controllers like deployments and replicas
Scheduler	Schedules pods to run on available nodes

Other Useful Commands

Command	Description
`kubectl apply -f [file].yaml`	Create/update resources using a YAML file
`kubectl delete -f [file].yaml`	Delete resources defined in a YAML file
`kubectl edit [resource] [name]`	Edit a resource in place
`kubectl get all`	List all resources in the current namespace
`kubectl top nodes`	Show resource usage by nodes
`kubectl top pods`	Show resource usage by pods

This cheat sheet should give you a solid starting point for working with Kubernetes. Let me know if you'd like further details on any specific area!

Kubernetes Cheat Sheet

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