Amazon EKS | Data Volumes Overview.

 

Here's twtech overview of Amazon EKS – Data Volumes:

 Amazon EKS – Data Volumes Overview

In Amazon Elastic Kubernetes Service (EKS), data volumes refer to storage volumes used by pods to persist and share data.

Volumes in Kubernetes, including those on EKS, allow containers to store and retrieve data across restarts, re-creations, or multiple container instances.

 Types of Volumes in EKS

EKS supports multiple volume types through Kubernetes:

1. Amazon EBS (Elastic Block Store)

• Usage: Most common for persistent data storage.
• Characteristics:
• Block-level storage.
• Attached to a single EC2 node (i.e., a pod cannot move across nodes unless EBS is reattached).
• Supports ReadWriteOnce (RWO) access mode.
• Use Cases: Databases, stateful apps (e.g., MongoDB, PostgreSQL).

2. Amazon EFS (Elastic File System)

• Usage: Shared file storage across multiple pods and nodes.
• Characteristics:
• POSIX-compliant NFS file system.
• Multiple pods across AZs can read/write to the same volume.
• Supports ReadWriteMany (RWX).
• Use Cases: Shared config files, web content, media libraries.

3. Ephemeral Volumes (emptyDir, hostPath, etc.)

• Usage: Temporary storage tied to pod lifecycle.
• Characteristics:
• Data lost when pod is deleted.
• Useful for caches, scratch data.
• Examples:
• emptyDir: Created when pod starts.
• hostPath: Maps a host node directory into the pod.

4. FSx for Lustre

• Usage: High-performance shared storage.
• Use Case: HPC, ML workloads requiring fast, parallel I/O.

 Persistent Volume (PV) and Persistent Volume Claim (PVC)

To use volumes in Kubernetes:

1. PersistentVolume (PV): Abstraction of actual storage.
2. PersistentVolumeClaim (PVC): Request for storage by a pod.

Kubernetes schedules PVCs to match available PVs or triggers dynamic provisioning (e.g., automatically creating an EBS volume).

 Dynamic Volume Provisioning in EKS

EKS supports dynamic provisioning using StorageClasses, which define:

• The type of storage (EBS, EFS).
• Parameters (volume type, size, IOPS, etc.).
• Provisioner (e.g., ebs.csi.aws.com for EBS CSI driver).

Example of a StorageClass for EBS:

# yaml

apiVersion: storage.k8s.io/v1

kind: StorageClass

metadata:

  name: twtech-ebs-sc

provisioner: ebs.csi.aws.com

parameters:

  type: gp3

  fsType: ext4

 twtech-Best Practices

• Use EBS for stateful single-node workloads, like databases.
• Use EFS for shared, read/write access across pods.
• Use StorageClasses for dynamic provisioning.
• Use CSI drivers (EBS CSI, EFS CSI) for better management and flexibility.
• Monitor usage and automate volume resizing when needed.

 CSI (Container Storage Interface) Drivers in EKS

EKS supports CSI (Container Storage Interface) drivers:

• Amazon EBS CSI driver: For managing EBS volumes.
• Amazon EFS CSI driver: For EFS with Fargate integration.
• Amazon FXs CSI driver: For Luster & NetApp ONTAP
• Installed via EKS Add-ons or Helm charts.