Hey there! Hearing a lot about Kubernetes but not sure what it is? As a fellow technology geek, let me walk you through a comprehensive introduction to Kubernetes. I‘ve been working with containers and Kubernetes for years, so I‘m excited to share my insider knowledge to help you wrap your head around this transformative technology.
What is Kubernetes?
Kubernetes (also known as K8s) is an open-source system that automates the deployment, scaling, and management of containerized applications. Originally designed by Google based on their internal Borg system, Kubernetes builds upon 15 years of Google‘s experience running containers in production.
In a Kubernetes environment, you describe your desired state for your application containers, and Kubernetes works to keep your actual state matched to what you specified. This automation provides huge benefits like:
- Maximizing hardware utilization
- Ensuring your application is always available
- Easy scaling to meet demand
- Avoiding vendor lock-in
So in summary, Kubernetes handles the heavy lifting involved with operating container infrastructure at scale, allowing you to focus on building great applications.
Kubernetes Hits its Stride
While initially released in 2014, Kubernetes adoption has skyrocketed in the last few years as companies embrace containers and microservices. According to the Cloud Native Computing Foundation, Kubernetes has now become the industry standard with:
- 78% of companies using containers now using Kubernetes
- 90% of global organizations expected to use containers by 2022
- $50 billion market size projected by 2025
As you can see, Kubernetes is dominating as the orchestration engine for containerized workloads in the cloud native era. Its ability to simplify container operations for developers while providing production-grade reliability has been a game changer.
My Perspective as a Kubernetes Practitioner
As someone who has worked directly with Kubernetes in production for many years now, I‘ve seen firsthand the benefits it can provide compared to cobbling together container orchestration yourself. The abstractions make it simple yet powerful.
My teams are able to ship updates much faster and scale up rapidly thanks to the automation Kubernetes provides. It handles so many difficult tasks around managing containers that plagued us before. Although Kubernetes itself has a learning curve, it ultimately makes our lives as developers much easier.
So from the trenches, I can say Kubernetes delivers immense value. It has become the cornerstone for building scalable, resilient applications in the cloud native world.
Why Kubernetes is Important
Kubernetes provides a consistent method to deploy and manage containerized applications in an automated fashion. As applications grow larger and teams scale up, orchestrating all the interconnected container pieces manually becomes extremely difficult.
Some key reasons Kubernetes has become so popular:
Reliability – Automatically restarts failed containers and reschedules them onto healthy nodes. Critical for always-on applications.
Scalability – Trivially scale applications up and down to meet demand by changing the replica count. Supports both horizontal and vertical scaling.
Declarative Deployments – Declare the desired state in a manifest file and Kubernetes makes it happen. No complex container management scripts needed.
Portability – Write applications once then deploy anywhere – on-prem or any cloud. Kubernetes handles differences between environments.
Community – As an open source CNCF project, Kubernetes benefits from a huge community building integrations and contributing improvements.
Ecosystem – Many related open-source tools like Helm and Prometheus provide extensions for Kubernetes in areas like package management, service mesh, monitoring, log aggregation and more.
According to a CNCF survey, the top reasons organizations use Kubernetes are:
- Accelerate application development – 49%
- Improve infrastructure efficiency – 46%
- Standardize development practices – 41%
- Improve developer productivity – 40%
- Improve application reliability – 34%
As you can see, Kubernetes delivers important benefits around velocity, efficiency, and reliability when building modern applications. For any company adopting microservices architectures and DevOps practices, Kubernetes is the way forward over managing containers manually.
How Kubernetes Works
A Kubernetes deployment consists of a cluster containing a control plane that manages nodes that run containerized applications.
Control Plane Components
The control plane is the brains of Kubernetes, controlling and scheduling containers on nodes:
Kubernetes Master – The main controlling component with various processes like the API server, scheduler, controller manager, and more.
etcd – A highly available key-value store that persists the cluster desired state and configuration.
The nodes are the worker machines that run applications inside containers:
Kubelet – The agent on each node responsible for communicating with the master and starting/stopping containers.
Kube-proxy – A network proxy and load balancer that distributes connections across nodes and pods.
Container Runtime – The software that runs containers like Docker, containerd, CRI-O, etc.
This separation of concerns between the control plane and nodes provides modularity and resiliency. The master oversees the cluster while nodes focus on running applications.
Now let‘s look at some of the main abstractions Kubernetes uses for managing containerized applications.
Kubernetes Building Blocks
Kubernetes provides various primitives for deploying and connecting containerized applications:
The smallest deployable units that encapsulate one or more containers running together on a node. Pods represent a single instance of an application.
An abstraction that defines a logical set of pods and enables discovery and load balancing for them. Services get their own IP address and DNS name.
Ingress resources route external traffic from outside the cluster to Kubernetes services inside the cluster. They provide load balancing, SSL/TLS termination, and name-based virtual hosting.
ConfigMaps & Secrets
Configure applications by decoupling configuration from container images. ConfigMaps store non-confidential data while Secrets store sensitive data.
Volumes provide data persistence by attaching structured storage resources into containers. Used for stateful apps like databases.
Partitions cluster resources between multiple applications and teams by virtually separating Kubernetes namespaces. Avoid naming collisions.
Declaratively defines the desired state for pods and replicasets. Handles orchestrating rollouts and rollbacks of application changes.
These are some of the main resources you‘ll interact with when deploying applications on Kubernetes.
Managing Applications on Kubernetes
There are several main approaches for managing Kubernetes applications:
Imperative Commands – kubectl CLI gives you direct control over the cluster and resources.
Declarative Manifests – Declare the desired state for apps, pods, deployments as YAML files applied to the cluster.
Kubernetes API – The Kubernetes API serves as the source of truth for the cluster. You can integrate and automate using API client libraries.
Dashboards – Visualize and manage cluster resources through web dashboards like the Kubernetes Dashboard.
In practice, you‘ll likely use a combination of these approaches – kubectl and YAML for app deployment, the API for automation, and dashboards for visibility. This provides flexibility in managing infrastructure and applications.
The core Kubernetes project focuses on the base orchestration system. But to simplify running Kubernetes in production, many managed platforms and distributions have emerged:
|Kubernetes Engine||Managed Kubernetes on Google Cloud Platform (GCP)|
|Elastic Kubernetes Service (EKS)||Managed Kubernetes on Amazon Web Services (AWS)|
|Azure Kubernetes Service (AKS)||Managed Kubernetes on Microsoft Azure|
|OpenShift||Enterprise Kubernetes from RedHat with enhancements for developers|
|Rancher||Turnkey Kubernetes platform that runs anywhere|
|DigitalOcean Kubernetes||Simplified managed Kubernetes on DigitalOcean|
These hosted platforms handle provisioning, upgrades, scaling, networking, monitoring, security, and more operational aspects so you don‘t have to run Kubernetes yourself. They integrate Kubernetes with their public cloud or infrastructure.
So for getting started and testing apps, I recommend using a managed Kubernetes offering first before trying to self-manage Kubernetes clusters.
Learning and Getting Started with Kubernetes
Based on my experience helping teams adopt Kubernetes, here is my recommended path for getting started:
Learn Kubernetes basics through an online course. Visual explanations will make concepts clearer. I suggest Kubernetes Course on Pluralsight.
Practice locally using Minikube or MicroK8s single-node clusters. Apply what you learned by deploying sample apps.
Use a managed Kubernetes offering like Google GKE or Amazon EKS to deploy apps to production-grade clusters.
Consider getting Kubernetes certifications to validate and share your skills.
The most crucial thing is gaining experience using Kubernetes hands-on. Containerization and Kubernetes represent a major shift left for developers. Invest time upfront in learning Kubernetes properly rather than trying to wing it. This will pay off greatly in your ability to build and deploy applications moving forward.
Kubernetes is the Standard for Container Orchestration
Kubernetes has clearly emerged as the open source cloud native standard for deploying and running containerized applications in production. Its design and ecosystem of tools provide a robust platform for building the next generation of modern, portable, resilient applications.
This introduction covers the key concepts and components to give you a solid starting point. Let me know if you have any other questions! I‘m happy to provide advice based on my real-world experience with Kubernetes.
The effort to learn Kubernetes is absolutely worth it. Mastering these skills will enable you to thrive in the world of containers, microservices and cloud native development. Welcome to the future!