📖 Introduction
Hi everyone, in today's episode we'll dive into Kubernetes, one of the most impactful tools in modern software development. We'll learn why Kubernetes is a game-changer for developers and why almost every big company relies on it. Our journey will be supported by several examples taken from some success stories in the modern world of software engineering such as AirBnb, Spotify and the European Organization for Nuclear Research.
Originally designed by Google in 2014 as an upgrade of their internal cluster manager "Borg" to handle Google’s massive scale of operations, Kubernetes started gaining traction among developers in 2015. Over the years, the Kubernetes community has grown exponentially, numbering thousands of contributors all over the world. This growth has consolidated Kubernetes' position as one of the largest and most influential open-source projects globally, second only to Linux in terms of its impact on modern IT infrastructure.
Why Developers Love Kubernetes 💓
🖥️ Simplifies Work for Developers
Kubernetes helps manage applications by automating tasks like deploying, scaling, and updating. This means less manual work for developers and IT teams, allowing them to focus on building and improving apps. Kubernetes helps companies deliver reliable, scalable, and cost-effective applications.
📈 Scalability Made Simple
As companies grow, so do their applications. But there's a catch: as applications scale up, managing all the containers manually becomes a real nightmare. Nowadays, companies can easily reach dozens or hundreds of microservices, leading to highly complex infrastructures to orchestrate.
What if a node fails? How do you manage traffic and handle request peaks? For a simple website, this might not be a problem, but for a big company, this is an everyday challenge.
Kubernetes makes it easy to scale up or down based on how many people are using an app. This ensures everything runs smoothly, even during busy times. Think of Kubernetes as a conductor for your applications!
Kubernetes also supports horizontal and vertical scaling, allowing applications to handle increased traffic and workload demands efficiently. By adjusting the number of running instances or the resources allocated to each instance, Kubernetes ensures that applications can scale up or down seamlessly, thereby enhancing performance and reliability.
| Horizontal scaling | Vertical scaling | |
|---|---|---|
| Aim | Increasing/decreasing the number of machines | Adjusting the CPU memory on existing machine |
| Best Use In | stateless applications | stateful applications |
| Scalability | High | Limited to maximum resources |
| Fault tolerance | Higher, one fault doesn't effect other | lower, one fault can effect other |
| cost | Can be cost-effective | Can lead to higher costs |
Table 1: Examples of horizontal and vertical scaling
🤸♀️ Adapts to Changing Needs (Flexibility)
Kubernetes let companies quickly deploy new features or make updates. It also works with multiple cloud services, so businesses can use the best tools for their needs without being locked into one provider.
The Kubernetes community has developed several strategies and best practices to tackle challenges related to scalability and high availability. These include using multi-replica deployments, configuring readiness and liveness probes, implementing Pod Disruption Budgets, and utilizing node affinity and anti-affinity rules. These strategies help ensure that services remain operational and accessible even during node maintenance or failures. For example, Spotify and Airbnb benefit from these HA strategies by maintaining continuous service availability despite underlying infrastructure changes or failures.
💵 Cost Efficiency Through Automation
Imagine this: You and your team have successfully proposed and worked on a new feature and the Head of Software Engineering has approved it.
What could go wrong? A hidden bug resulting in downtime! Downtime can be costly for your application leading to a bad user experience, a damaged reputation, and a loss of profit.
Kubernetes helps an application remain accessible with minimal interruptions. By efficiently managing resources, Kubernetes helps reduce costs. Companies only use what they need, avoiding wasted computing power.
🥳 Ensuring High Availability with Kubernetes
Kubernetes plays a critical role in enhancing the high availability and reliability of microservices. It offers a powerful framework for building highly available applications by running multiple replicas of containers and managing them through controllers like ReplicaSets and Deployments. These controllers ensure that the desired number of replicas is always running while maintaining service availability even during failures. The Kubernetes community has developed several strategies and best practices to tackle challenges related to scalability and high availability. These include using multi-replica deployments, configuring readiness and liveness probes, implementing Pod Disruption Budgets, and utilizing node affinity and anti-affinity rules. These strategies help ensure that services remain operational and accessible even during node maintenance or failures.
Open-Source 🧑💻
With over 120k+ commits, 112k stars, and a community of over 7k developers, Kubernetes is the second-largest project on GitHub. Its vast and active community ensures continuous development, with regular updates and continuous monitoring from contributors worldwide. This collaborative effort not only accelerates innovation but also ensures the platform remains secure, scalable, and adaptable to evolving industry needs. The growing ecosystem around Kubernetes, which includes many plugins, tools, and integrations, showcases its importance in today's technology landscape.
🧑💻 Success Stories: How Top Companies Use Kubernetes
Big names like Airbnb and Spotify use Kubernetes to keep their services running smoothly and to handle millions of users. They’ve seen better performance and faster updates, helping them stay ahead of competitors.
🏩 Airbnb: From Monolith to Microservices
Initially, Airbnb operated on a Ruby on Rails monolith known as Monorail. However, as the company grew, this monolithic architecture became a bottleneck, leading to dependency issues and operational inefficiencies. To address these challenges, Airbnb began migrating to a service-oriented architecture SOA in 2018, which helped in managing dependencies more effectively and enhancing scalability
Airbnb leverages Kubernetes to efficiently manage its cloud infrastructure and handle the daily fluctuations in traffic.
Airbnb has transitioned almost all of its online services from manually orchestrated AWS EC2 instances to Kubernetes, significantly enhancing its operational efficiency.
Airbnb's infrastructure comprises thousands of nodes spread across nearly a hundred Kubernetes clusters 😲. The Kubernetes Cluster Autoscaler plays a crucial role in dynamically adjusting the size of these clusters based on current demand. This dynamic scaling ensures that Airbnb can handle peak travel seasons without unnecessary overspending during off-peak times.
🎵 Spotify: Scaling Music Streaming with Kubernetes:
Spotify was an early adopter of microservices and Docker, deploying containerized microservices across its fleet of virtual machines (VMs) with a homegrown container orchestration system called Helios. However, by late 2017, it became apparent that a small team managing Helios was less efficient compared to adopting a solution supported by a larger community. Recognizing the potential benefits of Kubernetes, Spotify decided to migrate to this open-source container orchestration platform. Jai Chakrabarti, Director of Engineering, Infrastructure and Operations at Spotify, noted that Kubernetes not only complemented Helios but eventually replaced it due to its feature richness and robust community support. This migration allowed Spotify to handle its rapidly growing infrastructure more effectively, automate deployments, and ensure high availability across different regions.
One of the significant challenges Spotify faced before adopting Kubernetes was managing the scalability strain during major music events, album releases, or viral song trends. Manually scaling resources to handle traffic surges was slow and often led to service disruptions. Kubernetes provided a solution by enabling Spotify to automate resource scaling and improve resource utilization, ensuring a seamless user experience even during peak demand periods.
⚛️ CERN: Managing Big Data with Kubernetes:
The European Organization for Nuclear Research is a great example of big data and high-demanding infrastructure. Currently, CERN stores over 500 petabytes (1PB = 1000 TB) of data and the number is expected to increase to 5,000 PB with future upgrades to its accelerators. To put it into perspective, nowadays, common computers use a typical 1TB hard disk to store data, if we stacked 5,000,000 1TB hard drives on top of each other, the stack would be 130 kilometers high 😮. This is an extreme example but is useful to help us visualize the magnitude of the problem.
To address the challenges of data storage, processing, and scalability, CERN has increasingly turned to Kubernetes. It has enabled CERN to handle its extreme data workload peaks, particularly during periods leading up to major conferences. The organization is looking towards a more hybrid infrastructure, leveraging both on-premises resources and public cloud services to meet these demands efficiently.
The transition to Kubernetes was also driven by the need for scalable infrastructure to support Continuous Integration and Continuous Delivery (CI/CD) workflows. The traditional Docker-based solution became obsolete, prompting CERN to adopt Kubernetes Runners, which provide a more flexible and scalable environment for GitLab CI/CD pipelines.
Furthermore, the application of Kubernetes extends to the efficient utilization of GPU resources for machine learning tasks. CERN's Large Hadron Collider (LHC) generates billions of particle collisions per second, resulting in hundreds of petabytes of data that need to be reconstructed and analyzed.
🚀 Conclusions
Kubernetes has transformed modern IT by simplifying app management, enabling scalability, and optimizing resources. Its adoption by companies like Airbnb, Spotify, and CERN highlights its value in handling complex infrastructures and ensuring high availability.
In the next episode, I'll dive into how Kubernetes infrastructure works.
Thank you for reading! 🙏
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