Kubernetes services are a way to manage network communication within a cluster of containers managed by Kubernetes. Services provide a stable IP address and DNS name and can load balance incoming requests to a set of replicas of a deployed application. These abstracts allow users to access it consistently regardless of the current state of the underlying resources.
Types of Kubernetes services
1. Cluster IP:
A Cluster IP service is a type of Kubernetes service that exposes an application running within a cluster to the network. It provides stable IP addresses for accessing pods within the cluster and can load-balance incoming traffic to the pods. The Cluster IP service is only accessible from within the cluster and does not expose the application to the internet.
2. Node Port:
A Node Port service shows an application running within a cluster to the network by assigning a static port on each node in the cluster. This allows external traffic to access the application through the node IP addresses and the assigned Node Port. The Node Port service provides load-balancing for incoming traffic across the pods running the application. The Node Port service is accessible from outside the cluster and is useful for applications.
3. Load Balancer:
A Load Balancer tracks an application running within a cluster to the network by creating a load balancer in the underlying cloud infrastructure. The load balancer automatically distributes incoming traffic across the pods running the application, providing load balancing and high availability. Load Balancer services are accessible from outside the cluster and are useful for applications that need to be accessed from the internet. The underlying cloud infrastructure provisions the load balancer and manages its configuration, while Kubernetes manages the mapping between the service and the underlying pods.
4. External Name:
An External Name service in Kubernetes is a special type of service that maps a service to a DNS name instead of a selector. This type of service is useful when you want to access an external resource by a DNS name and do not need to load balance traffic across multiple replicas of that resource. When you create an External Name service, you specify the external DNS name, and the service’s ’.spec.externalname’ field is set to that name. When a client tries to access the service, it is redirected to the external DNS name.
Each type of service provides different levels of network accessibility and is suited for different use cases, depending on the needs of the application being deployed.
In conclusion, Kubernetes services are a fundamental component in the Kubernetes ecosystem, providing communication and networking capabilities to the containers within a cluster. Services enable the containers to communicate with each other and also allow external traffic to access the application. With its flexible and scalable nature, Kubernetes services play a crucial role in delivering robust and reliable applications in cloud-native environments.
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