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Services: ClusterIp, NodePort, LoadBalancer, ExternalName

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Objective

Learn and get practice with the different types of kubernetes services.

Story time

Once upon a time, three intrepid souls roamed the land: Brave Ben, Resourceful Rina, and Fearless Fred. One fateful day, they set their sights on the legendary Cluster Castle, a fabled dungeon rumored to conceal secrets of immense power and knowledge.

Approaching the castle's entrance, they resolved to compete in their quest for the coveted treasures within. Each determined to claim the prized bounty first.

As they ventured forth, they diverged onto separate paths, destined for an unexpected encounter with the mystical guardians: ClusterIP, NodePort, LoadBalancer, and ExternalName.

ClusterIP

Brave Ben, opting for a solitary journey into the depths, utilized his teleportation magic to navigate the labyrinthine tunnels. Amidst the maze, he encountered ClusterIP, a spectral guide. This entity ensured seamless communication within the dungeon's confines, shielding him from external interference. The aid of ClusterIP was akin to possessing an exclusive map of the tunnels, accessible only to those within its bounds.

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NodePort

Meanwhile, Resourceful Rina circled the castle walls until she stumbled upon a concealed door. Upon entering, she was greeted by NodePort, the stalwart guardian. NodePort facilitated external access to specific chambers within the dungeon, acting as a direct bridge between the interior and the outside world. It served as a key to unlock designated areas, granting entry to predetermined zones.

guard

LoadBalancer

Finally Fearless Fred decided to boldly march through the main entrance, confronting a massive gate guarded by the imposing LoadBalancer. This formidable gatekeeper permitted numerous adventurers to access the dungeon's chambers. The LoadBalancer represented the necessity for a broader entry point, providing an accessible map to guide all who sought exploration within.

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ExternalName

In the shadows, a lesser-known sorcerer, ExternalName, watched over a hidden passage leading to a realm beyond the dungeon's confines. This sorcerer acted as a conduit to an external service, allowing adventurers to access resources located outside the dungeon's domain. ExternalName served as a gateway to distant lands, offering a glimpse into worlds beyond imagination.

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Conclusion

Though taking different routes, ClusterIP, NodePort, LoadBalancer, and ExternalName guided the adventurers through the Cluster Castle, each ensuring access to its treasures while safeguarding its secrets with their protective measures. The four adventurers all emerged victorious, and returned laden with newfound knowledge and riches.

Exercise: Managing Kubernetes Services - ClusterIP, NodePort, LoadBalancer, and ExternalName

Objective: The objective of this exercise is to gain hands-on experience in managing different types of Kubernetes services: ClusterIP, NodePort, LoadBalancer, and ExternalName.

Requirements: - Access to a Kubernetes cluster (locally installed or cloud-based) - kubectl command-line tool installed and configured to communicate with the Kubernetes cluster

Instructions: 1. Create a ClusterIP Service: - Use either a YAML configuration file or the command line to create a ClusterIP service to connect an app to a port.

  1. Create a NodePort Service:

    • Define a NodePort service to connect an app to a port, allowing external access by specifying a node port.

  2. Create a Basic LoadBalancer Service:

    • Establish a basic LoadBalancer service to connect an app to a port.

  3. Create an ExternalName Service:

    • Set up an ExternalName service to map a service to a DNS name.

  4. Confirm Service Creation:

    • Verify that the services have been created correctly.

  5. Edit a Service:

    • Modify or add a port, or link to a different element in at least one of the services.

  6. Clean Up Resources:

    • Remove resources once the exercise is completed to prevent unnecessary costs or cluttering of the Kubernetes cluster.

Example Solution Steps:

Assuming you have a Kubernetes cluster set up and a sample application deployed named "my-app":

  1. Create ClusterIP Service: 

    kubectl create service clusterip my-app-clusterip --tcp=80:8080

  2. Create NodePort Service: 

    kubectl create service nodeport my-app-nodeport --tcp=80:8080 --node-port=30000

  3. Create LoadBalancer Service: 

    kubectl create service loadbalancer my-app-loadbalancer --tcp=80:8080

  4. Create ExternalName Service: 

    kubectl create service externalname my-app-external --external-name=example.com

  5. Verify Service Creation: 

    kubectl get services

  6. Edit a Service: 

    kubectl edit svc my-app-clusterip

  7. Clean Up Resources: 

    kubectl delete service my-app-clusterip my-app-nodeport my-app-loadbalancer my-app-external

These steps should provide a hands-on experience in managing various types of Kubernetes services and familiarize you with their configurations and functionalities.

To get a full insight of the services, their characteristics and yaml files configuration, you can find here the full official documentation.