What are Kubernetes Services?
Kubernetes services are defined as a logical abstraction that represents a particular set of pods where an application is running. It also defines an access policy used for that group of pods. Pods are the smallest execution units that you can create and manage in Kubernetes. One pod represents a group of one or more containers (lightweight packages that represent a full runtime environment of an application and its dependencies) that share network resources and storage. Since the lifespan of Kubernetes pods is short, a service is used to assign a name and unique IP address (clusterIP) to a group of pods that provide specific functions (f.ex. web services). That IP address will remain intact as long as the service exists. In the end, the service’s role is to be a reliable endpoint for communication between applications (or components).
What are the best practices for Kubernetes?
Following the best practices when implementing Kubernetes is crucial to ensure reliability, security and scalability.
- When defining containers, specify resource requests and limits to improve Kubernetes' scheduling and ensure efficient resource usage.
- Remember to keep Kubernetes, nodes and applications up to date with security patches and the latest features for stability and security.
- Use labels for classification and annotations for non-identifying supplementary details to keep resources well-organized and provide additional information about objects.
- Maintaining comprehensive documentation about your cluster architecture, configurations and operational procedures is required.
Following these practices ensures a robust and scalable Kubernetes environment.
How to autoscale an application in Kubernetes?
Scaling an application in Kubernetes requires a different approach than with other services. Kubernetes autoscaling offers a mechanism to automatically scale up or down the number of pods of an application based on resource utilization or other user-defined triggers. As you monitor your application, there are two key things you need to keep an eye on. First, track how many users are interacting with your application. Second, examine your nodes' CPU and memory usage. Various cloud providers offer autoscaling functionality that uses metrics to determine when to start and stop new instances. Resource limits are a way to set a maximum value on a metric, like CPU or memory. If an application uses too much of a specific resource, autoscaling can respond by adding more instances of the application.
What are common problems when using Kubernetes?
There are several issues that can happen while using a Kubernetes service, most of which are dependent on the circumstances and the purpose for which the service has been deployed. For instance, let’s assume that it is impossible for a client to access a pod. In this case, you could be dealing with a number of things that would indicate that there is something very wrong with the service. Your service might not exist, or it is not defined correctly; your service's DNS name is not working in the cluster or the service itself doesn't have a proper DNS name or pods are not working as expected and are unstable. This is to say that, first, it is of utmost importance that you make sure you know what you’re doing when creating a new Kubernetes service, and second, that you (or somebody in your IT department) know how to fix the issues when they occur.
