• Level Up Coding
  • Posts
  • LUC #34: Unpacking Containerization: Transforming Software Development and Deployment

LUC #34: Unpacking Containerization: Transforming Software Development and Deployment

Plus, stateful vs stateless design — what's the difference, HTTP status codes explained, and how DNS lookup works

This week’s issue brings you:


A big thank you to our partner Postman who keeps this newsletter free to the reader.

You can now build API-driven applications visually. Postman Flows can chain requests, handle data, and integrate with other applications via webhooks. And it's available on Postman's free plan. Check it out.

Unpacking Containerization: Transforming Software Development and Deployment

Building and deploying applications comes with quite a lot of complexities. One of the most significant challenges is ensuring consistency across various environments, a disparity that often leads to deployment failures, increased development and testing complexity, among other issues.

Containerization addresses these challenges head-on. 

It's a solution that encapsulates applications and their dependencies into isolated, scalable containers, ensuring consistent performance across all environments, and streamlining modern software development and deployment. Containerization has set new benchmarks for efficiency and reliability in the field.

From Virtualization's Challenges to Containerization's Solutions

Before containerization came into the picture, virtualization was the solution of choice. It involved creating distinct virtual machines (VMs) on a single physical server but despite its innovation, virtualization had its flaws. This directly impacted server capacity and limited scalability and performance. This inefficiency was a key pain point that led to the need for a more streamlined and resource-efficient approach, paving the way for the development of containerization.

Software containers encapsulate an application along with its necessary libraries, dependencies, and configurations. In contrast to virtual machines, containers share the host system's kernel but maintain isolation for application processes. This setup allows each container to operate independently. An important outcome of this approach is that it facilitates consistent software operation across diverse computing environments. This means that an application will run the same way on a developer's laptop as it would on a cloud server, streamlining the transition from development to deployment without the added bulk of a full operating system, as in VMs.

Containerization involves three key components:

  • Container Engine: This is the runtime environment for containers. Examples include Docker, which allows the execution and management of containers.

  • Container Image: A lightweight, standalone executable package that includes everything needed to run the software. It ensures streamlined and efficient deployment.

  • Container Registry: Acts as a repository for storing container images. It aids in organizing and providing easy access to various software versions and configurations.

Benefits of Containerization

The use of containerization in software engineering provides quite a lot of advantages:

  • Efficiency and Consistency Across Environments: It resolves the "it works on my machine" dilemma by ensuring that software operates consistently from development to production, reducing environment-related discrepancies.

  • Scalability and Resource Utilization: Containers, being lightweight, enable more efficient use of resources compared to virtual machines, supporting better scalability with less hardware.

  • Simplified Deployment and Version Control: Deployment becomes smoother with containers due to their portability. This ease is crucial for continuous integration and deployment pipelines, and container images aid in effective version control.

  • Isolation and Enhanced Security: Containers provide isolation between applications, which minimizes the risk of system-wide issues and strengthens security. This isolation means vulnerabilities in one container don't easily affect others.

Key Tools and Technologies


Docker has become an indispensable tool in containerization. It has made a significant impact on how developers build, share, and run applications by simplifying the creation and management of containers thanks to its intuitive platform and comprehensive ecosystem of tools and services.


For container orchestration, Kubernetes has taken the lead. It automates the deployment, scaling, and management of containerized applications, particularly in complex and dynamic environments. Kubernetes is fantastic for managing large-scale container deployments, offering high availability and optimal resource usage. Its robust features and extensive scalability have made it the preferred choice for enterprises and developers.

While Docker and Kubernetes are central to containerization, tools like Docker Swarm and OpenShift also play significant roles. Docker Swarm provides streamlined clustering for Docker containers, while OpenShift offers enhanced features such as automated installation and comprehensive lifecycle management. Despite the presence of these tools, Kubernetes remains the dominant choice for container orchestration, thanks to its unmatched scalability and strong community support.

Integration with Cloud Providers

Containerization integrates seamlessly with cloud platforms. Its lightweight nature suits cloud environments very well, enabling rapid scaling and service orchestration. This synergy optimizes performance and cost-effectiveness across various cloud environments.

Containerization in the cloud is supported by several key cloud service provides:

  • AWS: Elastic Container Service (ECS) and Elastic Kubernetes Service (EKS) optimize containerized applications with AWS infrastructure.

  • Azure: Azure Container Instances (ACI) and Azure Kubernetes Service (AKS) offer enhanced container deployment and management.

  • Google Cloud: Google Kubernetes Engine (GKE) specializes in Kubernetes-based container management.

These services simplify container deployment and orchestration, allowing developers to focus on application development.

In cloud-based CI/CD pipelines, containers play a pivotal role in ensuring consistent, reliable, and fast deployment cycles. They facilitate the creation of standardized environments for development, testing, and production, enhancing the efficiency of CI/CD practices. 

Simultaneously, the focus on security in containerized environments is paramount. Cloud providers offer specialized security tools and services for container monitoring.

Challenges and Considerations

While containerization offers significant benefits, it's important to acknowledge and address its challenges:

  • Container Complexity and Orchestration: Managing numerous containers, especially in large deployments, requires efficient orchestration tools to handle complexity.

  • Security in Containerized Environments: Containers improve security but also introduce specific challenges. Continuous vigilance and strong security practices are necessary to safeguard against vulnerabilities.

  • Performance Overhead and Resource Allocation: Containers are efficient yet can incur overheads. Proper resource allocation and management are key to optimizing performance.

It's important to note that these challenges are relatively minor compared to the advantages containerization brings. With the right tools and practices, these issues can be effectively managed. In doing so, organizations can fully leverage the power of containerization in their software development and deployment processes.

Final Thoughts

Containerization has significantly influenced software engineering, offering solutions for consistency, scalability, and efficiency challenges. Its evolution continues to shape software development and deployment, promising a more interconnected and efficient technological landscape.

Stateful vs Stateless Design (Recap)

“State” refers to stored information that systems use to process requests.

Stateful applications store data like user IDs, session information, configurations, and preferences to help process requests for a given user.

As applications grew in complexity and received increasing amounts of traffic, the limitations of stateful design became apparent. The rapid need for scalability and efficiency drove the popularity of stateless design.

With stateless design requests contain all the information needed to process it.

Stateless design has been pivotal in several areas including Microservices and Serverless Computing.

It does have it’s challenges though including larger requests sizes, and transmission inefficiencies.

Most applications pick a hybrid approach between stateful and stateless design depending on the needs and constraints of each component of the system.

HTTP Status Codes (Recap)

When a server receives a request from a client, it provides a response that includes a 3-digit status code that communicates the request’s outcome or status. HTTP status codes are divided into five categories, each identified by the first digit of the code:

🟣 Informational (1xx): The request was received, and the process is continuing.
🟢 Success (2xx): The request was successfully received, understood, and accepted.
🔵 Redirection (3xx): The request needs further action to be completed.
🔴 Client Error (4xx): The request contains incorrect syntax or cannot be fulfilled by the server.
🟠 Server Error (5xx): The server failed to fulfill a valid request.

How DNS Lookup Works (Recap)

  • DNS lookup converts human-readable domain names into IP addresses.

  • The process involves several components and back-and-forth communication to locate an IP address.

  • Caching is used at multiple levels to speed up the process.

  • If the initial checks of browser and OS caches don’t provide the required information, then the recursive resolver (usually ISP-managed) begins the search for the IP address on behalf of the user.

  • The recursive resolver communicates with several DNS servers to locate the nameserver that knows the IP address. 

  • Once the recursive resolver has retrieved the IP address, it then sends it back to the OS, the OS then sends it to the browser. The browser then fetches the website by making a request to the web server associated with the IP address.

That wraps up this week’s issue of Level Up Coding’s newsletter!

Join us again next week where we’ll explore big O notation, how the TCP handshake works, and how data processing systems work.