Automating PostgreSQL Backups on Kubernetes with CronJobs & Persistent Storage

Automate PostgreSQL Database Backups in Kubernetes with CronJobs and Azure File Share

Tired of manually backing up your PostgreSQL database? Automate the process using Kubernetes CronJobs, ConfigMaps, Persistent Volumes, and a lightweight PostgreSQL client Docker image.

In this step-by-step guide, you’ll learn how to:

✅ Create a Docker image with postgresql-client to perform backups.

✅ Use Kubernetes ConfigMaps to manage your backup script.

✅ Set up Persistent Volumes (PV & PVC) for storage.

✅ Automate backups using CronJobs with retention policies.

🛠 Prerequisites

Before getting started, ensure you have:

✔ A Kubernetes cluster on Azure Kubernetes Service (AKS) or another Kubernetes environment.

✔ kubectl installed and configured.

✔ A running PostgreSQL database in Kubernetes.

✔ Azure CLI installed for managing Azure resources.

✔ Docker installed to build and push images.

✔ A DockerHub or private container registry to store the backup image.

✔ Azure File Share created for storing backups persistently.

💡 Azure File Share will be used as persistent storage for backups.

Let’s get started! 🚀

💡 Why Automate PostgreSQL Backups?

Manual backups are risky — you might forget, or worse, data loss could occur before you act. With this Kubernetes-native solution, backups run automatically on a schedule, ensuring:

✔ Reliability — No missed backups!

✔ Security — Stored in Persistent Volumes (PVC).

✔ Efficiency — Old backups are deleted after 7 days.

🔧 Step 1: Build & Push the PostgreSQL Backup Docker Image

We’ll create a lightweight Docker image that only installs postgresql-client. This avoids unnecessary overhead from a full PostgreSQL installation.

📌 Dockerfile

# Use the official Ubuntu base image FROM ubuntu:latest  # Install PostgreSQL client RUN apt-get update && \  apt-get install -y postgresql-client && \  apt-get clean && \  rm -rf /var/lib/apt/lists/* # Set default command  CMD ["psql", "--version"] 

🛠 Build & Push the Image

docker build -t your-dockerhub-username/postgres-backup:latest . docker push your-dockerhub-username/postgres-backup:latest 

🔹 Replace your-dockerhub-username with your actual DockerHub username.

Step 2: Create Persistent Storage for Backups (PV & PVC)

We’ll store backups in an Azure File Share-backed Persistent Volume (PV & PVC).

📌 PersistentVolume (PV)

apiVersion: v1 kind: PersistentVolume metadata: name: postgresql-backup-pv spec: capacity: storage: 10Gi accessModes: - ReadWriteMany azureFile: secretName: "" # Add your secret here secretNamespace: "" shareName: "" # Add your Azure File Share name here readOnly: false 

📌 PersistentVolumeClaim (PVC)

apiVersion: v1 kind: PersistentVolumeClaim metadata: name: postgresql-backup-pvc spec: accessModes: - ReadWriteMany resources: requests: storage: 10Gi volumeName: postgresql-backup-pv 

🔹 Modify shareName and secretName based on your Azure setup.

Apply these:

kubectl apply -f pv.yaml kubectl apply -f pvc.yaml 

📜 Step 3: Create ConfigMap for Backup Script

We need to mount the backup.sh script inside the CronJob container. Instead of hardcoding it, let’s use a ConfigMap.

📌 backup.sh (Backup Script)

#!/bin/bash NAMESPACE=${NAMESPACE:-"default"} POSTGRES_SVC=${POSTGRES_SVC} POSTGRES_USER=${POSTGRES_USER} POSTGRES_DB=${POSTGRES_DB} BACKUP_DIR="/backup" DATE=$(date +"%Y-%m-%d") BACKUP_FILE="${BACKUP_DIR}/${POSTGRES_DB}_${DATE}.sql" TAR_FILE="${BACKUP_DIR}/${POSTGRES_DB}_${DATE}.tar.gz" POSTGRES_PASS=${POSTGRES_PASS} # Perform the backup PGPASSWORD="$POSTGRES_PASS" pg_dump -h "$POSTGRES_SVC" -U "$POSTGRES_USER" -d "$POSTGRES_DB" -F c -f "$BACKUP_FILE" # Compress the backup if [ $? -eq 0 ]; then tar -czf "$TAR_FILE" -C "$BACKUP_DIR" "$(basename "$BACKUP_FILE")" rm -f "$BACKUP_FILE" echo "Backup completed: $TAR_FILE" else echo "Backup failed!" exit 1 fi # Delete backups older than 7 days find "$BACKUP_DIR" -type f -name "${POSTGRES_DB}_*.tar.gz" -mtime +7 -exec rm -f {} \; 

📌 Create ConfigMap

kubectl create configmap backup-script --from-file=backup.sh
🔹 This mounts backup.sh in the CronJob without modifying the container.

⏳ Step 4: Automate Backups with a Kubernetes CronJob

The CronJob runs the backup script every night at 12:30 AM(UTC).

📌 CronJob YAML

apiVersion: batch/v1 kind: CronJob metadata: name: postgresql-backup spec: schedule: "30 0 * * *" # Runs daily at 12:30 AM UTC successfulJobsHistoryLimit: 1 failedJobsHistoryLimit: 1 jobTemplate: spec: template: spec: containers: - name: postgresql-backup image: your-dockerhub-username/postgres-backup:latest #update the values imagePullPolicy: IfNotPresent command: ["/bin/sh", "-c"] args: - | cp /scripts/backup.sh /tmp/backup.sh chmod +x /tmp/backup.sh until pg_isready -h "$POSTGRES_SVC" -U "$POSTGRES_USER"; do echo "Waiting for PostgreSQL to be ready..." sleep 5 done echo "Running backup script..." /tmp/backup.sh env: - name: POSTGRES_SVC value: "your-postgres-service" #update the values - name: POSTGRES_USER valueFrom: secretKeyRef: name: your-secret #update the values key: POSTGRES_USER - name: POSTGRES_PASS valueFrom: secretKeyRef: name: your-secret #update the values key: POSTGRES_PASSWORD - name: POSTGRES_DB value: "your-database" #update the values volumeMounts: - name: backup mountPath: /backup - name: script-volume mountPath: /scripts restartPolicy: OnFailure volumes: - name: backup persistentVolumeClaim: claimName: postgresql-backup-pvc - name: script-volume configMap: name: backup-script 

🔹 Replace your-dockerhub-username and your-postgres-service with actual values.

🛠 Apply CronJob

kubectl apply -f cronjob.yaml

🚀 Wrapping Up

Congratulations! 🎉 You have successfully automated PostgreSQL backups on Kubernetes using:

✔ Dockerized PostgreSQL client for backup execution.

✔ ConfigMaps to manage scripts.

✔ Persistent Storage (PV & PVC) to retain backups.

✔ CronJobs to schedule automated backups.

💬 What’s Next?

Want to take your PostgreSQL backup automation to the next level?

Hire me on Fiverr for customized solutions tailored to your needs!

Have any questions or improvements? Drop a comment below!
🔥 Have you automated PostgreSQL backups yet? Let me know in the comments! 🚀