Deploy Postgres on Kubernestes Cluster with Persistent Volume

Introduction

PostgreSQL, often called Postgres, is an open-source, object-relational database management system (DBMS). It is known for its robustness, scalability, and ability to handle complex queries and transactions.

Kubernetes is a free and open source container management tool, we can deploy and manage containerized applications across a cluster of nodes. It provides features such as automated rollouts and rollbacks, self-healing, load balancing, and scaling, all of which make it easier to manage and scale containerized applications.

In this post, We will show you how to deploy postgres database on Kubernetes cluster.

Step 1: Creating Configmap

We need to create a configmap for postgres database that container varibale’s value like postgres username, password and database.

To create configmap.

nano postgres-configmap.yaml

Paste the following configuration.

apiVersion: v1
kind: ConfigMap
metadata:
  name: postgres-config
  labels:
    app: postgres
data:
  POSTGRES_DB: postgres
  POSTGRES_USER: admin
  POSTGRES_PASSWORD: admin

We need to update relace the postgres’ username, password and database in real env and save and exit from the nano editor.

Step 2: Deploy Configmap

We need to deplot the configmap by using following command that will create a configmap.

To deploy the postgres’s configmap.

kubectl create -f postgres-configmap.yaml

To check configmap.

kubectl get configmap

Step 3: Creating Persistent Storage Volume and Persistent Volume Claim

To create storage configuration using YAML file

nano postgres-storage.yaml

Paste the following storage configuration.

kind: PersistentVolume
apiVersion: v1
metadata:
  name: postgres-pv-volume
  labels:
    type: local
    app: postgres
spec:
  storageClassName: manual
  capacity:
    storage: 10Gi
  accessModes:
    - ReadWriteMany
  hostPath:
    path: "/mnt/postgres_data"
---
kind: PersistentVolumeClaim
apiVersion: v1
metadata:
  name: postgres-pv-claim
  labels:
    app: postgres
spec:
  storageClassName: manual
  accessModes:
    - ReadWriteMany
  resources:
    requests:
      storage: 10Gi

We can change the host machine mount path and storage capity in real env and save and edit from nano editor.

To deploy the volume.

kubectl create -f postgres-storage.yaml

To verify volume and we need to also verify the PVC is connected to the PV.

kubectl get pvc

Step 4: Creating Postgres Deployment

We are good to create postgres deployment and we can configure configmap and volume configuration.

To create postgres deployment yaml file.

nano postgres-deployment.yaml

Paste the following configuration.

apiVersion: apps/v1
kind: Deployment
metadata:
  name: postgres
spec:
  replicas: 1
  selector:
    matchLabels:
      app: postgres
  template:
    metadata:
      labels:
        app: postgres
    spec:
      containers:
        - name: postgres
          image: postgres:12
          imagePullPolicy: "IfNotPresent"
          ports:
            - containerPort: 5432
          envFrom:
            - configMapRef:
                name: postgres-config
          volumeMounts:
            - mountPath: /var/lib/postgresql/data
              name: postgredb
      volumes:
        - name: postgredb
          persistentVolumeClaim:
            claimName: postgres-pv-claim

We can replace the postgres relica number, postgres version and others things save and edit from the nano editor.

To deploy the postgres.

kubectl create -f postgres-deployment.yaml

To verify the deployment.

kubectl get deployment

To validate postgres pod.

kubectl get pods

Step 5: Creating Postgres Service

Right now postgres pod is deploy and it should be running state but can not access the postgres from the network so that’s why we need to create service to make accessable in the network.

to create postgres service yaml configuration.

nano postgres-service.yaml

Paste the following configuration.

apiVersion: v1
kind: Service
metadata:
  name: postgres-service
  labels:
    app: postgres
spec:
  type: NodePort
  ports:
   - port: 5432
  selector:
   app: postgres

We need to replace the network type NodePort to LoadBalancer or ClusterIP as per your need, Leave on NodePort that will work with k8s node’s IP address, Save and edit from the nano editor.

To deploy postgres service.

kubectl create -f postgres-service.yaml

To validate postgres service.

kubectl get svc

To get Postgress Shell terminal.

kubectl exec -it [pod-name] --  psql -h localhost -U admin --password -p [port] postgres

Conclusion

We have successfully deployed the PostgreSQL database on the K8S cluster. If you are still facing problems, feel free to leave a commit.