DevOpsCube Posted December 13, 2022 Share Posted December 13, 2022 Learning Kubernetes can seem overwhelming. It’s a complex container orchestration system, that has a steep learning curve. But with the right roadmap and understanding of the foundational concepts, it’s something that any developer or ops person can learn. In this Kubernetes learning roadmap, I have added prerequisites and a complete Kubernetes learning path covering basic to advanced Kubernetes concepts. Prerequisites To Learn Kubernetes Before jumping into learning kubernetes, you need to have a fair amount of knowledge of some of the underlying technologies and concepts. Distributed system: Learn about distributed system basics & their use cases in modern IT infrastructure. Authentication & Authorization: A very basic concept in IT. However, engineers starting their careers tend to get confused. So please get a good understanding of learning from analogies. Key Value Store: It is a type of NoSQL Database. Understand just enough basics and their use cases. API: Kubernetes is an API-driven system. So you need to have an understanding of RESTFUL APIs. Also, try to understand gRPC API. It’s good to have knowledge. YAML: YAML stands for YAML Ain’t Markup Language. It is a data serialization language that can be used for data storage and configuration files. It’s very easy to learn and from a Kubernetes standpoint, we will use it for configuration files. So understanding YAML syntax is very important. Container: Container is the basic building block of kubernetes.The primary work of Kubernetes is to orchestrate containers. You need to learn all the container basics and have hands-on experience working on container tools like Docker or Podman. I would also suggest reading about Open container initiative and Container Runtime Interface (CRI) Service Discovery: It is one of the key areas of Kubernetes. You need to have basic knowledge of client-side and server-side service discovery. To put it simply, in client-side service discovery, the request goes to a service registry to get the endpoints available for backend services. In server-side service discovery, the request goes to a load balancer and the load balancer uses the service registry to get the ending of backend services. Networking Basis L4 & L7 Layers (OSI Layers) SSL/TLS: One way & Mutual TLS Proxy DNS IPTables IPVS Software Defined Networking (SDN) Virtual Interfaces overlay networking Learn Kubernetes Architecture Understanding Kubernetes architecture is not an easy task. The system has many moving parts that need to be understood in order for you to get a grip on what’s happening beneath the surface. While learning architecture, you will come across the concepts we discuss in the prerequisites. As Kubernetes is a complex system, trying to understand the core architecture could be a little overwhelming for DevOps Engineers. As you get more hands-on experience, you would be able to understand the core architecture better. Here is my suggestion. Learn the high-level architecture and key components involved in Kubernetes. If you are not able to grasp the concept, either you can spend time and do more research on a specific topic or you can learn the concept while doing hands-on. It’s your choice. Check out the Kubernetes Architecture guide to learn about all the Kubernetes components in detail. Overall you need to learn the following. Control plane components: Understand the role of each component like API server, etcd, Scheduler, and Controller manager. Worker node components: Learn about Kube Proxy, Kubelet, Container Runtime Addon Components: CoreDNS, Network plugins (Calico, weave, etc), Metric Server Cluster high availability: Most organizations use managed Kubernetes services (GKE, EKS, AKS, etc). So the cloud provider takes care of the cluster’s control plane’s high availability. However, it is very important to learn the high availability concepts in scaling the cluster in multi zones and regions. It will help you in real-time projects and devops interviews. Network Design: While it is easy to set up a cluster in an open network without restrictions, it is not that easy in a corporate network. As a DevOps engineer, you should understand the Kubernetes network design and requirements so that you can collaborate with the network team better. For example, When I was working with kubernetes setup on Google cloud, we used a CIDR pod range that was not routable in the corporate network. As a workaround, we had to deploy IP masquerading for the pod network. Kubernetes Cluster Setup There are many options to set up a Kubernetes cluster. Choose a cluster setup that you are comfortable with. Following are my cluster setup suggestions. Kubernetes the Hard Way: I would suggest you start with Kubernetes the hard way set up. It helps you understand all the configurations involved in bootstrapping a kubernetes cluster. The setup is based on google cloud. You can use the $300 free credits to complete the lab. Kubeadm Cluster Setup: Learning kubeadm cluster setup helps you in Kubernetes certification preparation. Also, it helps you automate Kubernetes cluster setup with best practices. Minikube: If you want to have a minimal development cluster setup, minikube is the best option. Kind: Kind is another local development Kubernetes cluster setup. Vagrant Automated Kubernetes: If you prefer to have a multi-VM-based local Kubernetes cluster setup, you can try the automated vagrant setup that uses Kubeadm to bootstrap the cluster. Also, you can use the free cloud credits and set up managed Kubernetes clusters. GKE (Google Cloud – $300 free credits) EKS (AWS – $300 free POC credits) DO Kubernetes (Digital Ocean – $200 free credits) Linode Kubernetes Engine (Linode Cloud – $100 Free credits) Understand Kubeconfig File Kubeconfig file is a YAML file that contains all the cluster information and credentials to connect to the cluster. As a Devops Engineer, You should learn to connect to kubernetes clusters in different ways using the Kubeconfig file. Because you will be responsible for setting up cluster authentication for CI/CD systems, providing cluster access to developers, etc. So spend some time, understanding the Kubeconfig file structure and associated parameters. Check out the complete Kubeconfig file guide to learn everything about the Kubeconfig file. Understand Kubernetes Objects And Resources You will quite often come across the names “Kubernetes Object” and “Kubernetes Resource” First, you need to Understand the difference between an object and a resource in kubernetes. To put it simply, anything a user creates and persists in Kubernetes is an object. For example, a namespace, pod, Deployment configmap, Secret, etc. Before creating an object, you represent it in a YAML or JSON format. It is called an Object Specification (Spec). You declare the desired state of the object on the Object Spec. Once the object is created, you can retrieve its details from the Kubernetes API using Kubectl or client libraries. As we discussed earlier in the prerequisite section, everything in Kubernetes is an API. To create different object types, there are API endpoints provided by the Kubernetes API server. Those object-specific api-endpoints are called resources. For example, an endpoint to create a pod is called a pod resource. So when you try to create a Kubernetes Object using Kubectl, it converts the YAML spec to JSON format and sends it to the Pod resource (Pod API endpoint). Learn About Pod & Associated Resources Once you have an understanding of Kubernetes Objects and resources, you can start with a native Kubernetes object called Pod. A pod is a basic building block of Kubernetes. You should learn all the Pod concepts and their associated objects like Service, Ingress, Persistent Volume, Configmap, and Secret. Once you know everything about a pod, it is very easy to learn other pod-dependent objects like deployments, Daemonset, etc. First, learn about the Pod Object specification (YAML). A typical Pod YAML contains the following high-level constructs. Kind Metadata Annotations Labels Selectors Once you have a basic understanding of the above, move on to hands-on learning. These concepts will make more sense when you do hands-on. Following are the hands-on tasks to learn about Pod and its associated objects. Deploy a pod Deploy pod on the specific worker node Add service to pod Expose the pod Service using Nodeport Expose the Pod Service using Ingress Setup Pod resources & limits Setup Pod with startup, liveness, and readiness probes. Add Persistent Volume to the pod. Attach configmap to pod Add Secret to pod multi-container pods (sidecar container pattern) Init containers Ephemeral containers Static Pods Learn to troubleshoot Pods Few advanced pod scheduling concepts. Pod Preemption & Priority Pod Disruption Budget Pod Placement Using a Node Selector Pod Affinity and Anti-affinity Learn Pod Dependent Objects Now that you have a better understanding of Pod and independent kubernetes resources, you can start learning about objects that are dependent on the pod object. While learning this, you will come across concepts like HPA (Horizontal Pod Autoscaling) and VPA (Verification Pod Autoscaling) Replicaset Deployment Daemonsets Statefulset Jobs & Cronjobs Learn Ingress & Ingress Controllers To expose applications to the outside world or end users, kubernetes has a native object called ingress. Many engineers get confused with Ingress due to less knowledge of Ingress controllers. Ensure you go through the concept of Ingress and Ingress controllers and understand it correctly. Because it is the base of exposing applications to the outside world. You can start with the following comprehensive guides. Kubernetes Ingress Explained Setting up Nginx Ingress Controller Also, learn about the Kubernetes Gateway API. it provides advanced features over Ingress. Learn End to End Microservices Application Deployment on Kubernetes Once you understand the basics of these objects, you can try deploying an end-to-end microservices application on Kubernetes. I would suggest you get a domain name and try setting up a microservice application from scratch and host it on your domain. You don’t need to develop an application for this. Choose any open-source microservice-based application and deploy it. My suggestion is to choose the open-source pet clinic microservice application based on spring boot. Following are the high-level tasks. Build Docker images for all the services. Ensure you optimize the Dockerfile to reduce the Docker Image size. Create manifests for all the services. (Deployment, Statefulset, Services, Configmaps, Secrets, etc) Expose the front end with service type ClusterIp Deploy Nginx Ingress controller and expose it with service type Loadbalancer Map the Loadbalancer IP to the domain name. Create an ingress object with a DNS name with the backend as a front-end service name. Validate the application. Learn About Securing Kubernetes Cluster Security is a key aspect of Kubernetes. There are many ways to implement security best practices in Kubernetes starting from building a secure container image. Following the native ways of implementing security in kubernetes. Service account Pod Security Context Seccomp & AppArmor Role Based Access Control (RBAC) Attribute-based access control (ABAC) Network Policies The following are the open-source tools you need to look at. Open Policy Agent Kyverno Kube-bench Kube-hunter Falco Learn About Kubernetes Configuration Management Tools Now that you have a good understanding of all Kubernetes objects and deploying applications on Kubernetes, you can start learning about Kubernetes configuration management tools. When you start working on a real-time project in an organization, you will see the usage of configuration management tools to deploy applications on Kubernetes. Because in organizations, there are different environments like dev, stage, pre-prod, and production. You cannot create individual YAML files for each environment and manage them manually. So you need a system to manage Kubernetes YAML configurations effectively. Following are the popular and widely adopted Kubernetes tools to manage YAML. Helm (Templating Engine) Kuztomize (Overlay Engine) Learn About Kubernetes Operator Pattern Kubernetes Operators is an advanced concept. To understand operators, first, you need to learn the following Kubernetes concepts. Custom resource definitions Admission controllers Validating & Mutating Webhooks To get started with operators, you can try setting the following operators on Kubernetes. Prometheus Operator MySQL Operator If you are a Go developer or you want to learn to extend/customize kubernetes, I would suggest you create your own operator using Golang. Learn Important Kubernetes Configurations While learning kubernetes, you might use a cluster in open network connectivity. So most of the tasks get executed without any issues. However, it is not the case with clusters set up on corporate networks. So following are the some of the custom cluster configurations you should be aware of. Custom DNS server Custom image registry Shipping logs to external logging systems Kubernetes OpenID Connect Segregating & securing Nodes for PCI & PII Workloads Learn Kubernetes Best Practices Following are the resources that might help and add value to the Kubernetes learning process in terms of best practices. 12 Factor Apps: It is a methodology that talks about how to code, deploy and maintain modern microservices-based applications. Since Kubernetes is a cloud-native microservices platform, it is a must-know concept for DevOps engineers. So when you work on a real-time kubernetes project, you can implement these 12-factor principles. Kubernetes Failure Stories: Kubernetes failure stories is a website that has a list of articles that talk about failures in Kubernetes implementation. If you read those stories, you can avoid those mistakes in your kubernetes implementation. Case Studies From Organizations: Spend time on use cases published by organizations on Kubernetes usage and scaling. You can learn a lot from them. Following are some of the case studies that are worth reading. Scheduling 300,000 Kubernetes Pods in Production Daily Scaling Kubernetes to 7,500 Nodes The Best Places to Learn The Best Resources to Learn Kubernetes Online Following are the list of the best online resource to learn Kubernetes practically. 1. The official Kubernetes Basics Tutorial The official Kubernetes website has browser-based hands-on kubernetes basic tutorials powered by Katacoda scenarios. It covers the following. Kubernetes basics Kubernetes configurations Stateless Application deployment Stateful application deployment Kubernetes services Kubernetes Security You can also look at official Kubernetes tasks to learn to implement Kubernetes concepts practically. It will also help you prepare for Kubernetes certifications. 2. DevOpsCube Kubernetes Tutorials DevOpsCube has 35+ comprehensive Kubernetes hands-on tutorials for beginners to advanced users. You will learn everything from Kubernetes architecture, Cluster setup, Deployments, best practices, package management, secret management, monitoring, logging, etc. 3. KillerCoda Interactive Tutorials If you want to learn Kubernetes from the comfort of your browser, Killercoda is a great option. It offers scenario-based learning playgrounds on the browser. Kubernetes Learning GitHub Repository The full Kubernetes learning guide is added to the Kubernetes learning path GitHub repo with links to all the free useful resources. This repo is maintained and contributed by community members and it has the following. Structured Kubernetes learning path Resources to deploy Kubernetes cluster for free. Kubernetes free learning resources Kubernetes hands-on tutorials. Kubernetes production deployment case studies Conclusion Learning a new technical skill takes hours of practice. You’ll certainly gain a good understanding of Kubernetes in the learning process, but the truth is that you never stop learning. I started my Kubernetes journey in 2014 and I learn new concepts and functionalities all the time. View the full article Quote Link to comment Share on other sites More sharing options...
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