Legacy applications are the silent killers of business efficiency. They’re monolithic, slow, and nearly impossible to scale. Every code update feels like a risk, with downtime looming like a dark cloud over your operations.  

The result?

Lost revenue, frustrated teams, and a system that’s becoming more of a liability than an asset.  

Imagine transforming your legacy application into a modern, agile system that scales effortlessly, reduces downtime to zero, and gives your business the competitive edge it desperately needs.  

With Docker on Google Cloud Platform (GCP), this transformation isn’t just possible - it’s within your reach. Dockerization allows you to containerize your legacy application, bringing it into the modern age with minimal disruption.  

The benefits?

Faster deployments, seamless scalability, and a system that’s finally aligned with your business goals.  

Here’s how you can achieve this transformation:  

Pre-Requisites:

• A Google Cloud account with billing enabled.  

• Artifact Registry and Google Kubernetes Engine APIs enabled.  

• A service account with permissions to push and pull images from Artifact Registry.  

• Access to the complete codebase of your legacy application (both Front End & Back End).  

• Docker pre-installed in the legacy application.  

Steps to Dockerize your Legacy Application:

1. Install Docker

Ensure docker is installed on your local machine, you can install it manually by the following steps,

Ubuntu/Debian

• sudo apt update

• sudo apt install docker-ce

       CentOS

• sudo yum check-update

• curl -fsSL https://get.docker.com/ | sh

• sudo systemctl start docker

       Redhat

• sudo dnf install https://download.docker.com/linux/centos/7/x86_64/stable/Packages/containerd.io-1.2.6-3.3.el7.x86_64.rpm

• sudo dnf install docker-ce

      Windows

• Open PowerShell and type the following commands

• Install-Module DockerMsftProvider -Force

• autosize-grow-threshold-percent <percent>

• Invoke-WebRequest -UseBasicParsing "https://raw.githubusercontent.com/microsoft/Windows-Containers/Main/helpful_tools/Install-DockerCE/install-docker-ce.ps1" -o install-docker-ce.ps1

• ./install-docker-ce.ps1

2. Create a Dockerfile

A Dockerfile is a script containing instructions on how to build a Docker image for your application, including application dependency files, add-ons, packages, code, and more. Here’s a basic example of a Dockerfile for a simple Node.js application:

3. Build the Docker Image

Once the Dockerfile is created, navigate to the directory where the Dockerfile is located and run the following command:

docker build -t **Dockerfile name**

After a period the docker file will be created.

4. Run the Docker Container Locally

Once the Docker build is complete, run it locally to ensure that the application is functioning without any issues. Use the following command:

docker run -p 9002:9002 **Dockerfile name**

or visit ‘http://localhost:9002’ to see your application in action.

5. Prepare your artifact registry in GCP

• Artifact registry in GCP is used to store, push and pull the docker images in GCP

• Go to Console - Artifact Registry - Enable Artifact registry API

• Create a new repository in artifact registry

Give your repository a friendly name (1), choose Docker in the format selector (2), and select your nearest region (3). Once the repository is created, note down the path.

Once the Artifact registry is configured, you need to configure the docker to authorize local clients to push and pull images in artifact registry, use the following command,

gcloud auth configure-docker asia-south1-docker.pkg.dev

6. Push Images from local to artifact registry

Once the authorization is completed, you can start pushing the Dockerfile to Artifact registry from your local client machine.

Use the following commands,

• Tag – Docker tags are a label assigned to a docker image to help identify it.

docker tag *Dockerfile name*:latest  asia-south1-docker.pkg.dev/**path**/node-js:latest

• Once the image is tagged , use the following command to push the docker images to Artifact registry

docker push asia-south1-docker.pkg.dev/**path**/node-js:latest

Once the image is pushed you can view the Dockerfile in Artifact registry.

You can then use the docker image to host your application in Google Kubernetes Engine or Cloud Run (Serverless) or Google Compute Engine.

Overcoming Challenges:

Complexity Management:

• Problem: Legacy applications are often monolithic, making them cumbersome to manage and update.

• Solution: By using Docker, you can break down these applications into microservices, making them easier to manage and update without affecting the entire system.

Frequent Downtime:

• Problem: Downtime is often required for updates and maintenance in legacy systems.

• Solution: Docker allows for seamless updates and rollbacks, significantly reducing or eliminating system downtime.

Scalability Issues:

• Problem: Scaling legacy applications can be resource-intensive and complicated.

• Solution: Dockerized applications can be managed and scaled more efficiently using orchestration tools like Kubernetes, which allows for automatic scaling based on demand.

Portability:

• Problem: Legacy systems are often tied to specific environments, making them less flexible.

• Solution: Docker containers are environment-agnostic, making it easy to move applications between different environments (e.g., development, staging, production) with minimal configuration.

Resource Efficiency:

• Problem: Legacy applications can be resource-heavy and inefficient.

• Solution: Docker containers use system resources more efficiently, allowing for better utilization and performance.

Conclusion:

Dockerizing your legacy application and deploying it on GCP provides numerous benefits, including improved scalability, portability, and resource efficiency. By following the steps outlined in this blog post, you can transform your legacy application into a modern, cloud-native solution. Embrace the power of Docker and GCP to modernize, simplify, and scale your applications, ensuring they are ready for the future. #TalkToQuadra

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