EBS CSI Driver

Before we dive into this section, make sure to familiarized yourself with the Kubernetes storage objects (volumes, persistent volumes (PV), persistent volume claim (PVC), dynamic provisioning and ephemeral storage) that were introduced on the Storage main section.

emptyDir is an example of ephemeral volumes, and we're currently utilizing it on the MySQL StatefulSet, but we'll work on updating it on this chapter to a Persistent Volume (PV) using Dynamic Volume Provisioning.

The Kubernetes Container Storage Interface (CSI) helps you run stateful containerized applications. CSI drivers provide a CSI interface that allows Kubernetes clusters to manage the lifecycle of persistent volumes. Amazon EKS makes it easier for you to run stateful workloads by offering CSI drivers for Amazon EBS.

In order to utilize Amazon EBS volumes with dynamic provisioning on our EKS cluster, we need to confirm that we have the EBS CSI Driver installed. The Amazon Elastic Block Store (Amazon EBS) Container Storage Interface (CSI) driver allows Amazon Elastic Kubernetes Service (Amazon EKS) clusters to manage the lifecycle of Amazon EBS volumes for persistent volumes.

To improve security and reduce the amount of work, you can manage the Amazon EBS CSI driver as an Amazon EKS add-on. The IAM role needed by the addon was created for us so we can go ahead and install the addon:

~$aws eks create-addon --cluster-name $EKS_CLUSTER_NAME --addon-name aws-ebs-csi-driver \

--service-account-role-arn $EBS_CSI_ADDON_ROLE

~$aws eks wait addon-active --cluster-name $EKS_CLUSTER_NAME --addon-name aws-ebs-csi-driver

Now we can take a look at what has been created in our EKS cluster by the addon. For example, a DaemonSet will be running a pod on each node in our cluster:

~$kubectl get daemonset ebs-csi-node -n kube-system

NAME           DESIRED   CURRENT   READY   UP-TO-DATE   AVAILABLE   NODE SELECTOR            AGE

ebs-csi-node   3         3         3       3            3           kubernetes.io/os=linux   3d21h

We also already have our StorageClass object configured using Amazon EBS GP2 volume type. Run the following command to confirm:

~$kubectl get storageclass

NAME            PROVISIONER             RECLAIMPOLICY   VOLUMEBINDINGMODE      ALLOWVOLUMEEXPANSION   AGE

gp2 (default)   kubernetes.io/aws-ebs   Delete          WaitForFirstConsumer   false                  3d22h

Now that we have a better understanding of EKS Storage and Kubernetes objects. On the next page, we'll focus on modifying the MySQL DB StatefulSet of the catalog microservice to utilize a EBS block store volume as the persistent storage for the database files using Kubernetes dynamic volume provisioning.