Services, Load Balancing, and Network Policies

In the previous chapter, we kicked off our Kubernetes Bootcamp to give you a quick but thorough introduction to Kubernetes basics and objects. We started by breaking down the main parts of a Kubernetes cluster, focusing on the control plane and worker nodes. The control plane is the brain of the cluster, managing everything including scheduling tasks, creating deployments, and keeping track of Kubernetes objects. The worker nodes are used to run the applications, including components like the kubelet service, keeping the containers healthy, and kube-proxy to handle the network connections.

We looked at how you interact with a cluster using the kubectl tool, which lets you run commands directly or use YAML or JSON manifests to declare what you want Kubernetes to do. We also explored most Kubernetes resources. Some of the more common resources we discussed included DaemonSets, which ensure a pod runs on all or specific nodes, StatefulSets to manage stateful applications with stable network identities and persistent storage, and ReplicaSets to keep a set number of pod replicas running.

The Bootcamp chapter should have helped to provide a solid understanding of Kubernetes architecture, its key components and resources, and basic resource management. Having this base knowledge sets you up for the more advanced topics in the next chapters.

In this chapter, you’ll learn how to manage and route network traffic to your Kubernetes services. We’ll begin by explaining the fundamentals of load balancers and how to set them up to handle incoming requests to access your applications. You’ll understand the importance of using service objects to ensure reliable connections to your pods, despite their ephemeral IP addresses.

Additionally, we’ll cover how to expose your web-based services to external traffic using an Ingress controller, and how to use LoadBalancer services for more complex, non-HTTP/S workloads. You’ll get hands-on experience by deploying a web server to see these concepts in action.

Since many readers are unlikely to have a DNS infrastructure to facilitate name resolution, which is required for Ingress to work, we will manage DNS names using a free internet service, nip.io.

Finally, we’ll explore how to secure your Kubernetes services using network policies, ensuring both internal and external communications are protected.

The following topics will be covered in this chapter:

• Introduction to load balancers and their role in routing traffic.
• Understanding service objects in Kubernetes and their importance.
• Exposing web-based services using an Ingress controller.
• Using LoadBalancer services for complex workloads.
• Deploying an NGINX Ingress controller and setting up a web server.
• Utilizing the nip.io service for managing DNS names.
• Securing services with network policies to protect communications.

As this chapter ends, you will understand deeply the various methods to expose and secure your workloads in a Kubernetes cluster.