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K8s Services - Photo Upload Service

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Kubernetes is a powerful container orchestration tool that simplifies the deployment and management of containerized applications at scale. In a Kubernetes cluster, a service is an abstraction layer that exposes a set of pods to the network. In this post, we'll dive deeper into Kubernetes services and their various types, features, and use cases.

What is a Kubernetes Service?

A Kubernetes service is a logical abstraction layer that groups a set of pods and exposes them to the network. Services provide a stable IP address and DNS name for the pods they target, regardless of their location or health status. This enables other applications inside or outside the cluster to access the pods via the service without knowing their specific IP addresses.

Services are defined using Kubernetes manifest files in YAML or JSON format. Each service has a unique name, a set of labels that match the labels on the targeted pods, and a service type that determines how the service is exposed to the network. Services can also have optional annotations, which provide additional metadata for the service.

Types of Kubernetes Services

Kubernetes supports four types of services, each with different networking characteristics and use cases:

  1. ClusterIP: The default type of service, which exposes the service on a cluster-internal IP address. This type is suitable for accessing the service within the cluster but not from outside the cluster.
  2. NodePort: Exposes the service on a static port on each worker node's IP address, which makes it accessible from outside the cluster. This type is useful for testing and development purposes but is not recommended for production environments due to security and scalability concerns.
  3. LoadBalancer: Creates an external load balancer that routes traffic to the service. This type is suitable for exposing the service to external clients and provides load balancing, high availability, and scalability.
  4. ExternalName: Maps the service to an external DNS name without creating a selector-based service. This type is useful for accessing external services from inside the cluster.