EKS Storage - Storage Classes, Persistent Volume Claims¶

Step-01: Introduction¶

We are going to create a MySQL Database with persistence storage using AWS EBS Volumes

Kubernetes Object	YAML File
Storage Class	01-storage-class.yml
Persistent Volume Claim	02-persistent-volume-claim.yml
Config Map	03-UserManagement-ConfigMap.yml
Deployment, Environment Variables, Volumes, VolumeMounts	04-mysql-deployment.yml
ClusterIP Service	05-mysql-clusterip-service.yml

Kubernetes Manifests¶

0102030405

#01-storage-class.yml
apiVersion: storage.k8s.io/v1
kind: StorageClass
metadata: 
  name: ebs-sc
provisioner: ebs.csi.aws.com
volumeBindingMode: WaitForFirstConsumer

#02-persistent-volume-claim.yml
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: ebs-mysql-pv-claim
spec: 
  accessModes:
    - ReadWriteOnce
  storageClassName: ebs-sc
  resources: 
    requests:
      storage: 4Gi

#03-UserManagement-ConfigMap.yml
apiVersion: v1
kind: ConfigMap
metadata:
  name: usermanagement-dbcreation-script
data: 
  mysql_usermgmt.sql: |-
    DROP DATABASE IF EXISTS usermgmt;
    CREATE DATABASE usermgmt;

#04-mysql-deployment.yml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql
spec: 
  replicas: 1
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate 
  template: 
    metadata: 
      labels: 
        app: mysql
    spec: 
      containers:
        - name: mysql
          image: mysql:5.6
          env:
            - name: MYSQL_ROOT_PASSWORD
              value: dbpassword11
          ports:
            - containerPort: 3306
              name: mysql    
          volumeMounts:
            - name: mysql-persistent-storage
              mountPath: /var/lib/mysql    
            - name: usermanagement-dbcreation-script
              mountPath: /docker-entrypoint-initdb.d #https://hub.docker.com/_/mysql Refer Initializing a fresh instance                                            
      volumes: 
        - name: mysql-persistent-storage
          persistentVolumeClaim:
            claimName: ebs-mysql-pv-claim
        - name: usermanagement-dbcreation-script
          configMap:
            name: usermanagement-dbcreation-script

#05-mysql-clusterip-service.yml
apiVersion: v1
kind: Service
metadata: 
  name: mysql
spec:
  selector:
    app: mysql 
  ports: 
    - port: 3306  
  clusterIP: None # This means we are going to use Pod IP

Step-02: Create following Kubernetes manifests¶

Create Storage Class manifest¶

https://kubernetes.io/docs/concepts/storage/storage-classes/#volume-binding-mode
Important Note: WaitForFirstConsumer mode will delay the volume binding and provisioning of a PersistentVolume until a Pod using the PersistentVolumeClaim is created.

Create Persistent Volume Claims manifest¶

# Create Storage Class & PVC
kubectl apply -f kube-manifests/

# List Storage Classes
kubectl get sc

# List PVC
kubectl get pvc 

# List PV
kubectl get pv

Create ConfigMap manifest¶

We are going to create a usermgmt database schema during the mysql pod creation time which we will leverage when we deploy User Management Microservice.

Create MySQL Deployment manifest¶

Environment Variables
Volumes
Volume Mounts

Create MySQL ClusterIP Service manifest¶

At any point of time we are going to have only one mysql pod in this design so ClusterIP: None will use the Pod IP Address instead of creating or allocating a separate IP for MySQL Cluster IP service.

Step-03: Create MySQL Database with all above manifests¶

# Create MySQL Database
kubectl apply -f kube-manifests/

# List Storage Classes
kubectl get sc

# List PVC
kubectl get pvc 

# List PV
kubectl get pv

# List pods
kubectl get pods 

# List pods based on  label name
kubectl get pods -l app=mysql

Step-04: Connect to MySQL Database¶

# Connect to MYSQL Database
kubectl run -it --rm --image=mysql:5.6 --restart=Never mysql-client -- mysql -h mysql -pdbpassword11

# Verify usermgmt schema got created which we provided in ConfigMap
mysql> show schemas;

AWS EKS - Elastic Kubernetes Service - Masterclass¶

Step-05: References¶

We need to discuss references exclusively here.
These will help you in writing effective templates based on need in your environments.
Few features are still in alpha stage as on today (Example:Resizing), but once they reach beta you can start leveraging those templates and make your trials.
EBS CSI Driver: https://github.com/kubernetes-sigs/aws-ebs-csi-driver
EBS CSI Driver Dynamic Provisioning: https://github.com/kubernetes-sigs/aws-ebs-csi-driver/tree/master/examples/kubernetes/dynamic-provisioning
EBS CSI Driver - Other Examples like Resizing, Snapshot etc: https://github.com/kubernetes-sigs/aws-ebs-csi-driver/tree/master/examples/kubernetes
k8s API Reference Doc: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#storageclass-v1-storage-k8s-io