Book Image

The DevOps 2.3 Toolkit

By : Viktor Farcic
Book Image

The DevOps 2.3 Toolkit

By: Viktor Farcic

Overview of this book

Building on The DevOps 2.0 Toolkit, The DevOps 2.1 Toolkit: Docker Swarm, and The DevOps 2.2 Toolkit: Self-Sufficient Docker Clusters, Viktor Farcic brings his latest exploration of the DevOps Toolkit as he takes you on a journey to explore the features of Kubernetes. The DevOps 2.3 Toolkit: Kubernetes is a book in the series that helps you build a full DevOps Toolkit. This book in the series looks at Kubernetes, the tool designed to, among other roles, make it easier in the creation and deployment of highly available and fault-tolerant applications at scale, with zero downtime. Within this book, Viktor will cover a wide range of emerging topics, including what exactly Kubernetes is, how to use both first and third-party add-ons for projects, and how to get the skills to be able to call yourself a “Kubernetes ninja.” Work with Viktor and dive into the creation and exploration of Kubernetes with a series of hands-on guides.
Table of Contents (18 chapters)
The End
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Claiming persistent volumes

Kubernetes persistent volumes are useless if no one uses them. They exist only as objects with relation to, in our case, specific EBS volumes. They are waiting for someone to claim them through the PersistentVolumeClaim resource.

Just like Pods which can request specific resources like memory and CPU, PersistentVolumeClaims can request particular sizes and access modes. Both are, in a way, consuming resources, even though of different types. Just as Pods should not specify on which node they should run, PersistentVolumeClaims cannot define which volume they should mount. Instead, Kubernetes scheduler will assign them a volume depending on the claimed resources.

We'll use pv/pvc.yml to explore how we could claim a persistent volume:

cat pv/pvc.yml 

The output is as follows:

kind: PersistentVolumeClaim
apiVersion: v1
  name: jenkins