Storage Beyond Regular Pod LifecycleĪpart from database applications, several other types of applications require long-term storage. Therefore, to host database applications in a Kubernetes cluster, you need to configure its pod to use PV so that the data is still available, even when the pod is no longer active. It becomes a huge problem if the data no longer exists when you restart or close the database application. A database application can collect and store millions of data from different sources while running. Providing Storage for Database Applicationsĭatabase applications require persistent storage that can last beyond their lifecycle. The common use cases for persistent volumes are providing storage for database applications and storage beyond the regular lifecycle of a pod.

It is important to note that Kubernetes does not restrict PVs to a namespace, which means that a pod in any namespace can claim a PV for storage. We will go into more detail about StorageClass later in this article. If there is no PV to match the PVC, the StorageClass dynamically creates a PV and binds it to the PVC. It is up to the developer to provide a PVC for storage, and then Kubernetes matches a suitable PV with the PVC. An administrator can create multiple PVs with different capacities and configurations. Once that is done, the pod claims any volume that matches its requirements (such as size, access mode, and so on). When a developer needs persistent storage for an application in the cluster, they request that storage by creating a persistent volume claim (PVC) and then mounting the volume to a path in the pod. Persistent volume (PV) is a piece of storage provided by an administrator in a Kubernetes cluster. In this article, you will learn about Kubernetes persistent volumes, including some relevant use cases and how they can be effectively set up and used. Some use cases for persistent volumes include providing storage for database applications, storage beyond the regular pod lifecycle, persistent storage for storing application logs, providing storage for storing user-generated files in content management applications, and so on. One of the most important functionalities of persistent volume is providing storage beyond the lifecycle of a pod. Kubernetes persistent volumes provide persistent storage for your containerized applications: even after restarting, the application pod will still have access to the previously stored data.

This is where Kubernetes’ persistent volumes come in. However, there are scenarios where you need to deploy applications that collect and store data that must be always available, even when you terminate the pod. Applications deployed on Kubernetes are often stateless, meaning that the applications do not rely on any previously saved data in the cluster to function properly. You should be able to see the index.html file from your local directory.Kubernetes is a useful tool for deploying and managing containerized applications. Pod//pod-pvc.yamlĤ - Port forward your Pod and access it with your browser. PersistentVolumeClaim/pvc.yamlģ - Spin up a Pod with nginx poiting where its default root directory points to your host’s directory (this example was tested on a docker-desktop kubernetes cluster)ġ - Create a PersistentVolume on your host monted on a local directory (add an index.html file in that directory with a hello world message) You can test a local PersistentVolume and a PersistentVolumeClaim with the following files.

Pvc.yaml - apiVersion : v1 kind : PersistentVolumeClaim metadata : name : persistent-volume-claim spec : accessModes : - ReadWriteOnce resources : requests : storage : 5Gi selector : matchLabels : pv : local storageClassName : hostpath

What is kubernetes pvc