In software development, containerisation is the process of bundling an application’s code, runtime, configuration files, libraries, and other dependencies into a single package. This package, which includes all the files a specific program needs to run, forms a lightweight executable known as a container. This container operates consistently across any infrastructure.
The concept of containerisation has been around since the 1970s. However, its adoption skyrocketed in the early 2010s with the advent of Docker (Aqua, 2020). Many leading tech companies, including Google, Intel, Amazon, and Digital Ocean, utilise containerisation in the development of their various products due to its numerous advantages. These benefits have contributed to the application container market’s expected growth to $29.7 Billion by 2030 (Verified Market Research, 2023). Some of these benefits include:
- Consistency: Containers ensure that applications run consistently across different environments, eliminating the “it works on my machine” problem.
- Isolation: Each container provides an isolated environment for the application, preventing conflicts with other applications or dependencies.
- Portability: Containers can be easily moved between different infrastructure environments, such as on-premises servers, public clouds, or hybrid clouds, ensuring seamless deployment.
- Scalability: Containers can quickly scale up or down based on demand, making them ideal for dynamic workloads and microservices architectures.
- Resource Efficiency: Containers are lightweight and consume fewer resources compared to traditional virtual machines, allowing for better resource utilisation and cost savings.
- Fast Deployment: Containers can be deployed rapidly, reducing time-to-market for new applications or updates.
- Version Control: Container images can be versioned, making it easy to roll back to previous versions if needed, ensuring a stable development and production environment.
How Does Containerisation Work?
Containerisation involves packaging an application along with its dependencies into a self-contained unit known as a container. The process begins with developers creating a container image, which includes the application code, runtime, libraries, and any other dependencies necessary for execution. These images are stored in a registry, allowing for easy distribution and sharing across teams and environments.
When a container is launched, the container engine pulls the corresponding image from the registry and creates an isolated instance on the host system. Containers share the underlying operating system kernel but have their own filesystem, process space, and network interfaces. This is similar to multiple tenants living in the same building, sharing the building’s infrastructure but maintaining their own separate living spaces. The container engine manages resource allocation, scheduling, and networking, enabling multiple containers to run simultaneously on the same host without interference.
Key Use Cases of Containerisation in Modern Software Development
Microservices Architecture: Containerisation is often used in microservices architectures where applications are broken down into smaller, independently deployable services. This enables easier scalability, maintenance, and updates of individual components.
Continuous Integration/Continuous Deployment (CI/CD): Containerisation facilitates CI/CD pipelines by providing consistent environments for testing, building, and deploying applications. It streamlines the development process, allowing for faster delivery of software updates.
Hybrid and Multi-Cloud Deployments: Containerisation enables seamless deployment of applications across hybrid and multi-cloud environments. It ensures portability and flexibility, allowing organisations to run workloads wherever it’s most cost-effective or strategically advantageous.
Big Data and Analytics: Containerisation simplifies the deployment and management of big data processing frameworks such as Apache Hadoop, Spark, and Kafka. It provides scalability and agility for processing large volumes of data efficiently.
High-Performance Computing (HPC): Containerisation is increasingly used in HPC environments to streamline the deployment of scientific computing applications and workflows. It ensures reproducibility, portability, and efficient resource utilisation in complex computational tasks.
Essential Tools
- Docker: Docker is the most popular containerisation platform, providing tools for building, distributing, and running containers. It simplifies the process of creating and managing containerised applications.
- Kubernetes: Kubernetes is an open-source container orchestration platform that automates the deployment, scaling, and management of containerised applications. It provides advanced features for service discovery, load balancing, and rolling updates.
- Jenkins: Jenkins is a widely used CI/CD tool that integrates seamlessly with containerisation platforms like Docker and Kubernetes. It automates the software delivery pipeline, from code integration and testing to deployment and monitoring.
- Terraform: Terraform is an infrastructure as a code tool that enables the provisioning and management of infrastructure resources using declarative configuration files. It can be used to define and deploy containerised environments across various cloud providers.
- Singularity: Singularity is a containerisation tool specifically designed for high-performance computing environments. It provides secure and efficient execution of containerised workloads in HPC clusters, with features tailored to scientific computing applications.
The Future of Software Deployment with Containerisation
Containerisation represents a paradigm shift in software deployment, offering unparalleled consistency, portability, and efficiency. By encapsulating an application and its dependencies into isolated units, containerisation ensures that software runs reliably across different environments, from local development to production, and even across different cloud platforms. As technology continues to evolve, containerisation will remain a critical tool in the software development landscape, driving innovation and enabling more agile and scalable solutions.