The trend of containerizing applications and managing them with an orchestrator like Kubernetes is still new. As with all budding technologies, there is a lot of curiosity and even some ambiguity around it. In this article, let us decode all about one aspect of Kubernetes – storage. You’ll get an understanding of the key concepts related to Kubernetes storage and be able to assess how your organization can better manage Kubernetes storage.
Why does Kubernetes storage matter?
Kubernetes is the leading container orchestration solution today. It enables Devops teams to proficiently deploy, operate, and scale containers in a cloud or on-prem environment. When you manage containerized applications, Kubernetes storage could prove immensely beneficial. The reason is that Kubernetes handles persistent and non-persistent data in a cluster in different ways. This helps in the creation of dynamic storage resources that can further cater to multiple types of applications.
If Kubernetes storage options are managed well you can greatly eliminate or minimize administrative overhead and can improve the performance of applications that perform data-intensive tasks.
Web services are getting modernized and the availability of applications 24/7 is what users expect. Also, developers are looking to increase deployment velocity to where they can ship code multiple times a day. In this scenario, containerization supports packaged software delivery to cater to these needs, allowing applications to be released more frequently without experiencing any downtime.
Key concepts of Kubernetes storage
There are different types of storage in Kubernetes. The most basic one is non-persistent or also called ephemeral storage. Every container comes with ephemeral storage by default. Ephemeral storage utilizes a temporary directory on the device that is hosting the Kubernetes pod. This is handy, convenient, and manageable but not sturdy. Non-persistent data is stored in a temporary storage volume and once the container or pod is shut down, the data is deleted.
Kubernetes also has several kinds of persistent storage such as file, block, or object storage options. These storage options can be setup in-house or purchased separately from cloud providers or data service providers.
As the fundamental storage component, Volumes play a significant role in the world of Kubernetes, helping provide storage to containers. A volume can aid in all kinds of storage such as network file systems (NFS), local storage devices, and cloud-based storage services.
PVs and PVCs
In order to enable persistent storage (storage that is not deleted on a container/pod removal), Kubernetes has a couple of key concepts. The first is a PersistentVolume (PV). This is a storage element defined by an administrator. It comes with its own data lifecycle which is separate from the lifecycle of Kubernetes pods. There are various implementation types for PVs such as iSCSI, and NFS.
Along with PVs another vital Kubernetes storage concept is a PersistentVolumeClaim (PVC). This is a request for storage from an application that needs to use a PV. The request would include details about the size of storage it needs or the way the storage needs to be used.
StorageClass plays a significant role in managing Kubernetes storage. It is a Kubernetes API and helps in the creation of new volumes as per requirement.
StorageClass enables Kubernetes to have different types of storage for different workloads.For instance, you can have fast SSD storage for one workload, while another uses remote storage volume that takes time but sends data over a network.
Container Storage Interface
This is a Kubernetes extension that makes storage more flexible. In essence, storage providers can create storage plugin once and run it on any container orchestrator, not just Kubernetes. This ties into Kubernetes’ original goal of enabling systems that can run anywhere, and aren’t dependent on any single vendor or single platform.
Best Practices for Kubernetes Storage
When managing storage for Kubernetes, the following are the recommendations to be followed:
- Have Persistent Volume Claims (PVCs) in the container configuration
- Do not have Persistent Volume (PVs) in container configuration
- Have a default StorageClass since PVCs do not have the capability of specifying which specific class will fail or succeed
- Have meaningful names for StorageClasses
Kubernetes Storage with Portworx
Portworx is a Kubernetes storage platform trusted in production by the world’s leading enterprises. It is an end-to-end storage and data management solution for all Kubernetes projects such as container-based CaaS, DBaaS, SaaS, and Disaster Recovery initiatives. It is known for providing a fully-integrated solution, complete with a whole range of services for modern persistent storage, data protection, data recovery, and data security. By being aware of the key storage components of Kubernetes, following best practices, and using a capable storage provider like Portworx, you can rest assured that your most valuable business asset, your data, is safe and highly available in Kubernetes.
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