Kubernetes Services & Load Balancing: Keep Your Microservices Happy and Reachable
Discover how Services and basic load balancing work in Kubernetes, How they load balance traffic and what is under the hood, so you can ensure that your workloads are easily and reliably reachable from whichever network endpoints they need to connect with and learn to manage your Kubernetes Services efficiently.
Services are a fundamental building block in most production-grade Kubernetes environments. By simplifying the process of configuring network connectivity for each workload inside Kubernetes, Services play a key role in scaling Kubernetes applications.
By the same token, understanding the best practices when configuring Kubernetes Services is essential for managing Kubernetes environments effectively. It’s a bit complicated, because there are multiple ways to set up Services, each with different pros and cons. Plus, to ensure that your Services actually behave the way you need, you must monitor them, which adds another layer of complexity to Services configuration and management.
To provide guidance on managing Kubernetes Services, this article explains how Services work in Kubernetes, How they load balance traffic and what is under the hood, so you can ensure that your workloads are easily and reliably reachable from whichever network endpoints they need to connect with.
What is a Kubernetes Service?
A Kubernetes Service is a type of object whose main purpose is to provide network access to a group of Pods. (Note that the term Service, like the names of other Kubernetes objects, is usually capitalized, and we're sticking with that style in this article.) You can use Services to make a group of pods accessible under a single, constant name.
In addition to providing a simple means of exposing Pods to other pods in the cluster, Services provide basic network load balancing functionality (as we explain in more detail below) out of the box.
Load balancing distributes requests to a group of Pods in an efficient way, and some further customizations are possible through the LoadBalancer Service type - depending on the cloud vendor.
How do Kubernetes Services work?
Kubernetes Services work by binding to a group of Pods based on the Pods' labels.
For example, if you want to create a Service for Pods that match the label my-app, you'd include this selector configuration in the YAML that you use to define the service: