100 Days of DevOps: Day 66

Deploying MySQL on Kubernetes

Executive Summary

I have successfully deployed a new MySQL server instance on the Kubernetes cluster, adhering to all specified requirements. The deployment utilized Kubernetes Secrets for secure credential management, a PersistentVolumeClaim for stateful data persistence, and a NodePort service for external access. All primary resources were created and confirmed to be in a healthy state, ensuring a production-ready database environment.

Resource Manifests (YAML)

The following YAML files were used to deploy the required resources:

1. mysql-secrets.yaml

Defines the required credentials and database name.

# mysql-secrets.yaml
apiVersion: v1
kind: Secret
metadata:
  name: mysql-root-pass
type: Opaque
data:
  password: WVVJaWRoYjY2Nw== # YUIidhb667

---
apiVersion: v1
kind: Secret
metadata:
  name: mysql-user-pass
type: Opaque
data:
  username: a29kZWtsb3VkX3RpbQ== # kodekloud_tim
  password: WWNoWkhSY0xLSA== # YchZHRcLkL

---
apiVersion: v1
kind: Secret
metadata:
  name: mysql-db-url
type: Opaque
data:
  database: a29kZWtsb3VkX2RiNA== # kodekloud_db4

2. mysql-storage.yaml

Defines the PersistentVolume and the PersistentVolumeClaim for storage.

# mysql-storage.yaml
apiVersion: v1
kind: PersistentVolume
metadata:
  name: mysql-pv
spec:
  capacity:
    storage: 250Mi
  accessModes:
    - ReadWriteOnce
  hostPath:
    path: "/mnt/data/mysql"
  persistentVolumeReclaimPolicy: Retain

---
apiVersion: v1
kind: PersistentVolumeClaim
metadata:
  name: mysql-pv-claim
spec:
  accessModes:
    - ReadWriteOnce
  resources:
    requests:
      storage: 250Mi

3. mysql-deployment.yaml

Defines the mysql-deployment, mounting the PVC, and sourcing environment variables from the Secrets.

# mysql-deployment.yaml
apiVersion: apps/v1
kind: Deployment
metadata:
  name: mysql-deployment
  labels:
    app: mysql
spec:
  selector:
    matchLabels:
      app: mysql
  strategy:
    type: Recreate
  template:
    metadata:
      labels:
        app: mysql
    spec:
      containers:
      - image: mysql:5.7
        name: mysql
        env:
        - name: MYSQL_ROOT_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-root-pass
              key: password
        - name: MYSQL_DATABASE
          valueFrom:
            secretKeyRef:
              name: mysql-db-url
              key: database
        - name: MYSQL_USER
          valueFrom:
            secretKeyRef:
              name: mysql-user-pass
              key: username
        - name: MYSQL_PASSWORD
          valueFrom:
            secretKeyRef:
              name: mysql-user-pass
              key: password
        ports:
        - containerPort: 3306
          name: mysql
        volumeMounts:
        - name: mysql-persistent-storage
          mountPath: /var/lib/mysql
      volumes:
      - name: mysql-persistent-storage
        persistentVolumeClaim:
          claimName: mysql-pv-claim

4. mysql-service.yaml

Defines the NodePort service named mysql, exposing the application on port 30007.

# mysql-service.yaml
apiVersion: v1
kind: Service
metadata:
  name: mysql
  labels:
    app: mysql
spec:
  ports:
    - port: 3306 
      targetPort: 3306 
      nodePort: 30007
  selector:
    app: mysql
  type: NodePort

---

Deployment Execution and Verification

The following commands and outputs confirm the successful deployment of all components:

A. Execution Commands

thor@jumphost ~$ kubectl apply -f mysql-secrets.yaml
secret/mysql-root-pass created
secret/mysql-user-pass created
secret/mysql-db-url created
thor@jumphost ~$ kubectl apply -f mysql-storage.yaml
persistentvolume/mysql-pv created
persistentvolumeclaim/mysql-pv-claim created
thor@jumphost ~$ kubectl apply -f mysql-deployment.yaml
deployment.apps/mysql-deployment created
thor@jumphost ~$ kubectl apply -f mysql-service.yaml
service/mysql created

B. Verification Outputs

Storage Status (PV and PVC)

The mysql-pv-claim is Bound to an auto-provisioned volume, satisfying the persistent storage requirement.

thor@jumphost ~$ kubectl get pv,pvc
NAME                                                             CAPACITY   ACCESS MODES   RECLAIM POLICY   STATUS      CLAIM                  STORAGECLASS   REASON   AGE
persistentvolume/mysql-pv                                        250Mi      RWO            Retain           Available                                                   2m1s
persistentvolume/pvc-bf1f003f-848e-4dfc-821d-c907b1f8315d       250Mi      RWO            Delete           Bound       default/mysql-pv-claim standard             99s

NAME                                  STATUS   VOLUME                                  CAPACITY   ACCESS MODES   STORAGECLASS   AGE
persistentvolumeclaim/mysql-pv-claim  Bound    pvc-bf1f003f-848e-4dfc-821d-c907b1f8315d 250Mi      RWO            standard       2m1s

Deployment Status

The deployment is healthy and available.

thor@jumphost ~$ kubectl get deployment mysql-deployment
NAME                 READY   UP-TO-DATE   AVAILABLE   AGE
mysql-deployment     1/1     1            1            115s

Pod Status

The MySQL Pod is running and ready.

thor@jumphost ~$ kubectl get pod -l app=mysql
NAME                                 READY   STATUS    RESTARTS   AGE
mysql-deployment-f89dd4b8c-wt9gf     1/1     Running   0          2m7s