In the world of containerized applications, Kubernetes has emerged as the standard for container orchestration, empowering developers to deploy and manage applications at scale. Docker images serve as the building blocks for these containers, and a reliable container registry like Nexus is essential for storing and distributing these images securely.
In this blog, we will explore how to migrate Docker images from one Kubernetes cluster to another using two separate Nexus registries. One for development and another for production. This process ensures a smooth and controlled transition of applications from dev to prod environments.
Prerequisites
Before we proceed, ensure that Docker is installed and properly configured on your machine with access to both the dev and prod Kubernetes clusters. Set up Docker credentials to authenticate with the Nexus registries.
1. Pull Image from Dev Registry
- Login to the dev Nexus registry and pull the desired image:
docker login <dev-nexus-registry-url>
docker pull <dev-nexus-registry-url>/<image-name>:<tag>
Replace <dev-nexus-registry-url>with the URL of your dev Nexus registry, <image-name> with the image’s name, and <tag> with the specific version or tag of the image.
2. Tag the Image for Prod Registry
- Retag the image with the prod registry’s address:
docker tag <dev-nexus-registry-url>/<image-name>:<tag> <prod-nexus-registry-url>/<image-name>:<tag>
3. Push the Image to Prod Registry
- Log in to the prod Nexus registry and push the retagged image:
docker login <prod-nexus-registry-url>
docker push <prod-nexus-registry-url>/<image-name>:<tag>
4. Verify the Pushed Image
- Confirm that the image has been successfully pushed to the prod Nexus registry by logging on to the nexus-prod console.
Conclusion:
Migrating Docker images between Kubernetes clusters using Nexus registries is a crucial process for safely moving applications from dev to production environments. By following the steps outlined in this blog, you can ensure a controlled transition, reducing the risk of discrepancies and unexpected behavior in your production environment.
Junior DevOps Engineer
Matt Mendez is a dedicated and passionate IT professional with a strong desire to help people as a consultant. With expertise in AWS, Linux, Terraform, and Google Cloud. He has acquired valuable certifications in these areas. Having hands-on experience in working with leading cloud platforms such as AWS, Azure, and Google Cloud, as well as proficient in managing infrastructure using Terraform and Kubernetes.
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