Containers, a pivotal DevOps technology, facilitate the definition of infrastructure as code, allowing for isolated environments crucial for testing and deploying applications. This tutorial explores the process of containerizing a Node.js application and automating its deployment to Azure Web Apps through Azure Container Registry, with the aid of CI/CD pipelines managed by CircleCI. Prerequisites include having Node.js, Azure, CircleCI, GitHub accounts, and necessary CLI tools installed. The tutorial guides users through creating a container registry on Azure, building a Docker image of a Node.js application, and deploying it to Azure Web Apps. It also details setting up continuous deployment via the Azure portal and automating the deployment process using CircleCI, which involves creating a configuration file to manage the workflow, including building, testing, and deploying the application. The tutorial concludes by highlighting the flexibility containers provide for developers to ensure seamless transitions between development and production environments, ultimately enhancing application reliability and performance.