SEPTEMBER 2022 GitOps for Kubernetes Essentials to Applications Hosted in Cloud-Native Ecosystems NINAD DESAI STAFF ENGINEER, INFRACLOUD CONTENTS • About GitOps for Kubernetes • Configuration Management Management in Kubernetes • GitOps for Kubernetes Essentials • Conclusion Git is the most widely used version control system, with more than 80 percent of its market share in today’s software industry running in Kubernetes. In this Refcard, we will dive into what GitOps means in the Kubernetes world, key principles, and the advantages for cloud-native ecosystems. ABOUT GITOPS FOR KUBERNETES Thanks

Contents 05 Foreword 07 Introduction 08 Chapter 1–What is GitOps? Origins in DevOps Kubernetes and containers Cloud-Native DevOps A DevOps Operating Model GitOps Principles Tools PipeCD Keptn Pulumi Kubernetes Operator Summary 18 Chapter 3–Templating Everything in Git Kustomize Helm Operators Combining Tools Summary The Path Structures Repositories Reflecting an Organizational Boundary Kubernetes Platform Administrator Kubernetes Application Developer Other Boundaries GitOps Repo Example

was officially named as ​“GitOps” in 2017​ by Weaveworks and has since become very popular for Kubernetes deployments. The concepts behind GitOps are quite straight-forward: ● Infrastructure as perform a Git operation such as creating a commit or opening a pull request Specifically for Kubernetes, GitOps says that you must not use `kubectl` to change the cluster state in an ad hoc manner. that it matches your Git state. Git hashes and commits however are only useful to developers and operators. Business stakeholders have no interest in which Git hash is now deployed at the cluster.

pull-requests” GitOps Benefits 5 GitOps is for Everyone Developers Operations Kubernetes Cluster Node 1 Kubernetes (K8s) is an open-source system for automating deployment, scaling, and management It is a resource scheduler KUBERNETES 101 6 Node Node Node Node Node Node Node Node 1 1 2 2 2 2 3 3 3 4 4 Applications OpenShift 4 - A Smarter Kubernetes Platform Automated, full-stack full-stack installation from the container host to application services Seamless Kubernetes deployment to any cloud or on-premises environment Autoscaling of cloud resources One-click updates for platform

运行以下命令，将现有节点标记为基础架构： 2. 编辑 GitOpsService 自定义资源(CR)以添加基础架构节点选择器： $ oc label node node-role.kubernetes.io/infra= 第 第 1 章 章 在基 在基础 础架 架构节 构节点上 点上运 运行 行 GITOPS CONTROL PLANE 工作 工作负载 负载 3 3. 在 GitOpsService GitopsService metadata: name: cluster spec: runOnInfra: true $ oc adm taint nodes -l node-role.kubernetes.io/infra infra=reserved:NoSchedule infra=reserved:NoExecute spec: runOnInfra: true tolerations: - effect: NoExecute key: infra value: reserved $ oc label node node-role.kubernetes.io/infra= 1 Red Hat OpenShift GitOps 1.13 基 基础 础架 架构节 构节点上的 点上的 GitOps 工作 工作负载 负载 4 1 1 2

What you have (current state) CD Why GitOps? Reliably and consistently configure multiple Kubernetes clusters and deployment 6 Capturing and tracing any change to clusters through Git history Application Delivery Model 8 Source Git Repository Config Git Repository Image Registry Kubernetes CI CD The GitOps Application Delivery Model Pull Request Push Pull Push Pull Pull Request Repository Image Registry CI The GitOps Application Delivery Model Config Git Repository Kubernetes Deploy Monitor Detect drift Take action CD Continuous Integration & Continuous Delivery

modern, cloud-native technologies. They need a way to confidently and securely deploy changes to Kubernetes that doesn’t require them to become experts in the orchestration tool. That’s where GitOps comes Change Lead Time Change Failure Rate MTTR vs. MTTF (mean time to recover/fail) P.3 Simplify Kubernetes operations using developer tools GitOps helps DevOps teams be more autonomous and productive GitOps is a standardized workflow for how to deploy, configure, monitor, update, and manage Kubernetes, it components, and all the applications that run on it. In GitOps, a Git repository contains

declaratively. The term GitOps was confined by Weaveworks in 2017 and was primarily aimed at managing Kubernetes deployments. However, now it has evolved into supporting other infrastructure management solutions middleman for facilitating communications between them. There are multiple available operators such as: Kubernetes Operator Terraform Cloud Operator Azure Service Operator Etc. GitOps workflow Now, Bitbucket: What’s The Difference & How To Choose How To Use Elastic Enterprise Search with GitHub Kubernetes Guide, a tutorial series Automation In DevOps: Why & How To Automate DevOps Practices What Is Cloud

Separation of Privileges 03 04 05 06 07 10 GitOps Hands On Tutorial Part 1: Spin up a Kubernetes Cluster Part 2: Fork the Sock Shop Repository Part 3: Setup CI and Connect a Container Registry your team can make changes and updates safely and securely to complex applications running in Kubernetes. Freedom of choice Because there is no single tool that can do everything required in your pipeline ship features. eBook 4 The Principles of GitOps The entire system is described declaratively. Kubernetes is just one example of many modern cloud native tools that are “declarative” and that can be treated

to the performance of engineering teams. Technology, in particular cloud native technology like Kubernetes and its ecosystem of projects, is now a core competency for organizations in all industries, from GITOPS? GitOps is a set of best practices and an operational model that reduces the complexity of Kubernetes and makes it easier to deliver on the promise of DevOps. More than a simple evolution of DevOps security guarantees with full audit trails. Another key concept behind GitOps is the fact that Kubernetes and its ecosystem of cloud native tools are declarative, as opposed to imperative, which allows