Data Management in Kubernetes

by Tola Ore-Aruwaji

Kubernetes has become the go-to solution for container orchestration, simplifying the deployment, scaling, and operations of application containers. However, managing data in Kubernetes can be a bit challenging due to its ephemeral nature. This post will delve into various strategies and tools that can be employed to handle data effectively within a Kubernetes environment.

Understanding Data Management in Kubernetes:

  • Persistent Volumes (PVs) and Persistent Volume Claims (PVCs): These are the foundational building blocks for managing storage in Kubernetes. PVs are resources that represent storage capacity, while PVCs are requests for storage capacity.  A Persistent Volume (PV) in Kubernetes is a piece of storage that has been provisioned by an administrator. It is a resource in the cluster that represents a storage volume, be it part of a local storage on a node, or an externally managed volume such as AWS EBS, Azure Disk, or a NFS share.

Example:

apiVersion: v1
kind: PersistentVolume
metadata:
  name: pv-name
spec:
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteOnce
  awsElasticBlockStore:
    volumeID: "<volume-id>"
    fsType: ext4
  • The Persistent Volume Claim is a request for storage by a user. It specifies the amount and characteristics of storage that a user needs, such as the access mode and size.
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: pvc-name
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 5Gi
  • Storage Classes: Storage Classes allow administrators to describe different classes of storage available within the cluster, which can be provisioned dynamically. With Storage Classes, administrators provide a way to describe the classes of storage they offer. They allow administrators to define different classes of storage with different performances. Dynamic provisioning is enabled through the use of Storage Classes. When a PVC specifies a Storage Class, a PV is dynamically provisioned based on the class’s configuration.
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata:
  name: gold
provisioner: kubernetes.io/aws-ebs
parameters:
  type: io1
  iopsPerGB: "10"

The cloud-native nature of Kubernetes allows it to integrate seamlessly with cloud-based storage solutions. For example:

  • A PV can be backed by a cloud storage resource such as an AWS Elastic Block Store (EBS) volume, Azure Disk, or Google Cloud Persistent Disk.
  • PVCs allow users to consume cloud storage resources transparently without needing to understand or manage the underlying infrastructure.
  • Storage Classes can be configured to use cloud-provisioned storage, enabling dynamic provisioning of cloud storage resources when needed.

Provision Storage in your Cloud (AWS, DigitalOcean, GCP)

For provisioned AWS Storage, you can use the Amazon EBS, which is suitable for databases and other transactional data needs, or you can use the Amazon Elastic File System (EFS) for shared file storage, perfect for content management systems and other shared data applications. Dynamic provisioning is a feature in Kubernetes that allows on-the-fly creation and deletion of storage resources. Utilize StorageClasses to define how storage volumes are provisioned. This automation not only reduces manual intervention but also ensures that applications have the storage they need when they need it.

Disaster Recovery

  • Disaster Recovery Planning: Establish a well-defined disaster recovery plan. This plan should detail the processes to follow in case of data loss or service disruptions, ensuring a swift recovery.
  • Multi-Region Deployments: Consider deploying your Kubernetes clusters across multiple regions to ensure data durability and availability. Multi-region deployments provide a geographical redundancy that can be crucial during regional outages. With our opensource workflows in the Cloud, disaster recovery can be automatically provisioned for you without worrying about your underlying infrastructure.

Integrating Kubernetes with CTO.ai

The integration of Kubernetes and CTO.ai facilitates a developed CI/CD pipeline where changes can be rapidly and safely deployed to a Kubernetes cluster. This involves:

  • Setting Up Environment: Ensuring Kubernetes and CTO.ai are configured and communicating successfully.
version: "1"
pipelines:
  - name: sample-expressjs-pipeline-do-k8s-cdktf:0.2.5
    description: Build and Publish an image in a DigitalOcean Container Registry
    env:
      static:
        - DEBIAN_FRONTEND=noninteractive
        - STACK_TYPE=do-k8s-cdktf
        - ORG=cto-ai
        - GH_ORG=workflows-sh
        - REPO=sample-expressjs-do-k8s-cdktf
        - BIN_LOCATION=/tmp/tools
      secrets:
        - GITHUB_TOKEN
        - DO_TOKEN
  • Automated Pipeline: Configuring CTO.ai to automatically build and test the application on code changes.
version: "1"
pipelines:
  - name: sample-expressjs-pipeline-do-k8s-cdktf:0.2.5
    description: Build and Publish an image in a DigitalOcean Container Registry
    env:
      static:
        - DEBIAN_FRONTEND=noninteractive
        - STACK_TYPE=do-k8s-cdktf
        - ORG=cto-ai
        - GH_ORG=workflows-sh
        - REPO=sample-expressjs-do-k8s-cdktf
        - BIN_LOCATION=/tmp/tools
      secrets:
        - GITHUB_TOKEN
        - DO_TOKEN
    events:
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.opened"
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.synchronize"
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.merged"
    jobs:
      - name: sample-expressjs-build-do-k8s-cdktf
        description: Build step for sample-expressjs-do-k8s-cdktf
        packages:
          - git
          - unzip
          - wget
          - tar
        steps:
          - mkdir -p $BIN_LOCATION
          - git version
          - git clone https://oauth2:$GITHUB_TOKEN@github.com/$GH_ORG/$REPO
          - docker build -f Dockerfile -t one-img-to-rule-them-all:latest .
          - docker tag one-img-to-rule-them-all:latest registry.digitalocean.com/$ORG/$REPO:$CLEAN_REF
          - docker push registry.digitalocean.com/$ORG/$REPO:$CLEAN_REF
services:
  - name: sample-expressjs-service-do-k8s-cdktf:0.1.6
    description: Preview of image built by the pipeline
    run: node /ops/index.js
    port: [ '8080:8080' ]
    sdk: off
    domain: ""
    env:
      static:
        - PORT=8080
    events:
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.opened"
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.synchronize"
      - "github:workflows-sh/sample-expressjs-do-k8s-cdktf:pull_request.merged"
    trigger:
      - build
      - publish
      - start

Strategic Data Management in the CI/CD Pipeline

Implementing a coherent data management strategy within the CI/CD pipeline involves:

  • Persistent Storage: Configuring PVs and PVCs in Kubernetes to manage and maintain essential data across deployments and updates.
  • Database Migrations: Ensuring database schema changes are smoothly transitioned within the CI/CD pipeline.
  • Data Backup and Recovery: Implementing backup and recovery strategies to protect data integrity during unforeseen issues or failures.
  • Security: Ensuring sensitive data is encrypted and secure throughout the CI/CD process.

Conclusion

Managing data in Kubernetes requires a strategic approach encompassing storage provisioning, data protection, and monitoring. With CTO.ai practices, organizations can ensure that their data remains secure, available, and optimized for performance in a Kubernetes environment.