Kubernetes has quickly become the backbone of modern cloud-native applications, and mastering its command-line tool, kubectl, is essential for every developer working in this ecosystem. In this cheat sheet, we've gathered some of the most commonly used commands to help you manage clusters, deploy applications, and troubleshoot issues efficiently.

Introduction to Kubernetes and Its Importance for Developers

Kubernetes has completely changed how we deploy, scale, and manage containerized applications.  As the de facto standard for container orchestration, it handles the complex tasks of container scheduling, load balancing, and service discovery. For developers, understanding Kubernetes commands is beneficial in the following ways:

Productivity

  • Focus on writing code instead of managing infrastructure

  • Automated deployment and scaling

  • Built-in best practices for container management

Reliability

  • Self-healing capabilities

  • Automated rollbacks

  • High availability configurations

Flexibility

  • Cloud provider agnostic

  • Support for multiple programming languages

  • Various deployment strategies

Cost Efficiency

  • Better resource utilization

  • Automated scaling based on demand

  • Reduced operational overhead

Basic Kubernetes Commands

These commands help you view, inspect, and manage your Kubernetes resources. Think of them as your basic toolkit for interacting with your cluster. The 'get' command shows you what's running, 'describe' gives you detailed information, and 'delete' helps you clean up resources. To get started, here are some foundational kubectl commands:

# Get information about resources

  • kubectl get pods                 # List all pods
  • kubectl get services            # List all services
  • kubectl get deployments        # List all deployments
  • kubectl get nodes              # List all nodes

# Describe resources in detail

  • kubectl describe pod <pod-name>
  • kubectl describe service <service-name>

# Delete resources

  • kubectl delete pod <pod-name>
  • kubectl delete service <service-name>

These basic commands allow developers to inspect and manage resources, facilitating day-to-day interactions with the cluster.

Pod Management Commands

Pods are where your applications live. These commands help you manage your application containers - from creating new pods to viewing their logs and even executing commands inside them. They're essential for debugging and maintaining your applications.

Here are key commands for managing them:

# Create and run pods

  • kubectl create -f pod.yaml
  • kubectl apply -f pod.yaml

# Execute commands in pods

  • kubectl exec -it <pod-name> -- /bin/bash

# View pod logs

  • kubectl logs <pod-name>
  • kubectl logs -f <pod-name>     # Follow log output

  • # Copy files to/from pods

  • kubectl cp <pod-name>:/path /local/path

These commands are indispensable for managing pods, investigating issues, and debugging applications in real-time.

Service and Networking Commands

Services enable network access to your applications. These commands help you set up networking between pods and expose your applications to the outside world. They're crucial for making your applications accessible and managing traffic flow. These commands help manage networking aspects:

# Expose deployments as services

kubectl expose deployment <name> --port=8080

# Forward ports for local access

kubectl port-forward <pod-name> 8080:80

# Get service endpoints

kubectl get endpoints

# View service details

kubectl describe service <service-name>

Networking commands are vital for enabling communication between services and allowing external access when needed.

Scaling and Updating Resources

These commands help you manage application scale and handle updates smoothly. Whether you need to scale up during high traffic or roll out a new version of your application, these commands make it possible while maintaining availability. 

# Scale deployments

kubectl scale deployment <name> --replicas=3

# Update deployments

kubectl rollout status deployment/<name>

kubectl rollout history deployment/<name>

kubectl rollout undo deployment/<name>

# Autoscale deployments

kubectl autoscale deployment <name> --min=2 --max=5

These commands help maintain high availability, ensuring applications remain responsive during scaling and updates.

Troubleshooting Kubernetes Clusters

When issues arise, these commands become your best friends. They help you understand what's happening in your cluster, identify problems, and gather information needed for solving them. From checking logs to monitoring resource usage, these commands are essential for maintaining healthy clusters.

# Debug pods

kubectl describe pod <pod-name>

kubectl logs <pod-name> --previous

# Check cluster health

kubectl get events

kubectl top pods

kubectl top nodes

# View resource usage

kubectl cluster-info

kubectl get componentstatuses

Effective troubleshooting is essential for maintaining cluster health and resolving issues promptly.

Conclusion

This cheat sheet covers the essential Kubernetes commands that developers need in their daily work. By mastering these commands, you'll be better equipped to manage Kubernetes clusters efficiently. Remember that while these commands are powerful, they should be used with proper understanding and caution in production environments.

Keep this reference handy, and you'll find yourself more confident in managing Kubernetes resources. As you grow more comfortable with these basic commands, you can explore more advanced Kubernetes features and operations.

Pro Tips:

  • Always use --dry-run flag when trying new commands

  • Set up command aliases for frequently used commands

  • Use kubectl explain to learn more about resource types

  • Practice these commands in a test environment first