GitOps Guide to the Galaxy (Ep 14): Exploring CI with Tekton

Now that we've looked at other continuous integration (CI) tools, let's see how Tekton stacks up. Tekton is a young yet powerful CI tool for Kubernetes and OpenShift that's optimized for building and deploying cloud-native, microservice-based applications. When it comes to CI, there are lots of options, each with a slightly different set of features, so we'll look at why you'd want to use it and dive into the features Tekton offers.

About Tekton:
Tekton is a powerful and flexible open-source framework for creating CI/CD systems, allowing developers to build, test, and deploy across cloud providers and on-premise systems.
https://tekton.dev/

Follow us:
Christian Hernandez https://twitter.com/christianh814
Chris Short https://twitter.com/ChrisShort

What is GitOps Guide to the Galaxy?
Every other Thursday at 3am ET hosts Christian Hernandez and Chris Short sit down to discuss everything in the GitOps universe, from end-to-end CICD pipelines to creating Git workflows.

Subscribe to Red Hat's YouTube channel: https://www.youtube.com/redhat/?sub_confirmation=1

About OpenShift:
Red Hat OpenShift is an open source container application platform based on the Kubernetes container orchestrator for enterprise application development and deployment.
Openshift.com https://red.ht/33Fh6uV
OpenShift on github https://github.com/openshift/
OpenShift on redhat.com https://red.ht/2o4ccDk

Presentation on YouTube: https://youtu.be/EmtvRPRyTy8
#RedHat #GitOps #Kubernetes

Transcript

1. Tekton High overview about the engine behind OpenShift Pipelines. GitOps Guide to the Galaxy 1 Christian Hernandez Cloud Platforms BU
2. GENERAL DISTRIBUTION Why Cloud-Native CI/CD? WHAT IS CI/CD? 2 Traditional CI/CD Cloud-Native CI/CD Designed for Virtual Machines Designed for Containers and Kubernetes Require IT Ops for CI engine maintenance Pipeline as a service with no Ops overhead Plugins shared across CI engine Pipelines fully isolated from each other Plugin dependencies with undefined update cycles Everything lifecycled as container images No interoperability with Kubernetes resources Native Kubernetes resources Admin manages persistence Platform manages persistence Config baked into CI engine container Configured via Kubernetes ConfigMaps
3. GENERAL DISTRIBUTION Why Cloud-Native CI/CD? WHAT IS CI/CD? 3 Traditional CI/CD Cloud-Native CI/CD Designed for Virtual Machines Designed for Containers and Kubernetes Require IT Ops for CI engine maintenance Pipeline as a service with no Ops overheard Plugins shared across CI engine Pipelines fully isolated from each other Plugin dependencies with undefined update cycles Everything lifecycled as container images No interoperability with Kubernetes resources Native Kubernetes resources Admin manages persistence Platform manages persistence Config baked into CI engine container Configured via Kubernetes ConfigMaps
4. CONFIDENTIAL Designator 4 OpenShift Pipelines
5. GENERAL DISTRIBUTION 5 Governed by the Continuous Delivery Foundation Contributions from Google, Red Hat, Cloudbees, IBM, Pivotal and many more An open-source project for providing a set of shared and standard components for building Kubernetes-style CI/CD systems OPENSHIFT PIPELINES
6. GENERAL DISTRIBUTION 6 Tekton Concepts TEKTON CONCEPTS Step Run commands in a container with volumes, env vars, etc Task A list of steps that run sequentially in the same pod Pipeline A graph of tasks executed in a certain order Task Run An invocation of a task with inputs and outputs Pipeline Run An invocation of a pipeline with inputs and outputs Condition An check that can determine if a task should be executed Pipeline Resource Inputs and outputs to tasks and pipelines (git, image, etc) Catalog A collection of reusable tasks Triggers A Tekton sub-project to start pipelines based on events
7. GENERAL DISTRIBUTION Steps 7 • Run command or script in a container • Kubernetes container spec ◦ Env vars ◦ Volumes ◦ Config maps ◦ Secrets TEKTON CONCEPTS - name: build image: maven:3.6.0-jdk-8-slim command: [“mvn”] args: [“install”] - name: parse-yaml image: python3 script:|- #!/usr/bin/env python3 ...
8. GENERAL DISTRIBUTION Task 8 Task Step Step Step Step TEKTON CONCEPTS Example Tasks: Maven Install, AWS CLI, Kubectl Deploy, Security Scan, etc • Defines a unit of work to be executed • A list of steps to run sequentially • Step containers run in the task pod • Has inputs, outputs and parameters • Workspaces and results for sharing data • Can run independent of pipelines
9. GENERAL DISTRIBUTION 9 Maven Task Example kind: Task metadata: name: maven spec: params: - name: goal type: string default: package steps: - name: mvn image: maven:3.6.0-jdk-8-slim command: [ mvn ] args: [ $(params.goal) ]
10. GENERAL DISTRIBUTION TaskRun TEKTON CONCEPTS 10 • Runs a Task to completion in a pod • References or embeds a Task spec • Provides input to Tasks ◦ Parameters ◦ Resources ◦ Service account ◦ Workspaces • Contains execution status and metadata TaskRun step status step status Pod step status container container container Task step step step refers to creates
11. GENERAL DISTRIBUTION Pipeline 11 • Define Tasks execution order (graph) ◦ Serial ◦ Parallel • Inputs and parameters • Retries tasks • Conditional task execution • Workspaces for sharing data between tasks • Reusable across projects Pipeline Task Task Task Task TEKTON CONCEPTS
12. GENERAL DISTRIBUTION Sharing Data Between Tasks TEKTON CONCEPTS 12 Task: results • Task exposes data as variables • Suitable for small pieces of data • Examples: commit id and branch name Task: workspaces • Shared volumes between tasks ◦ Persistent volumes ◦ Config maps ◦ Secrets • Suitable for large data • Examples: code, binaries, reports Pipeline Task Task /workspace/myw PersistentVolumeClaim
13. GENERAL DISTRIBUTION PipelineRun 13 TEKTON CONCEPTS PipelineRun • Runs a pipeline to completion • References or embeds a Pipeline spec • Creates TaskRuns to execute Tasks in the Pipeline • TaskRun pods may get scheduled on different node • Provides inputs and params to pipeline • Provides volumes for declared pipeline workspaces PipelineRun TaskRun Pod Pipeline creates TaskRun Pod TaskRun Pod Task Task Task
14. GENERAL DISTRIBUTION Triggers 14 TEKTON CONCEPTS Run pipelines based on events like HTTP webhooks on commit, pull request, etc EventListener TriggerTemplate webhook TriggerBinding How to map webhook JSON payload to variables What resources to create (e.g. PipelineRun) using the variables from payload mapping Interceptors PipelineRun Filter or modify webhook payload e.g. match branch or files changes
15. GENERAL DISTRIBUTION Task Catalog TEKTON CONCEPTS 15 • Catalog of reusable Tasks ◦ Image build: buildah, kaniko, jib, buildpacks, etc ◦ Source-to-Image: Java, Python, Go, Ruby, etc ◦ Language specific: maven, gradle, go, … ◦ More to come soon • Import and compose pipelines • Available catalogs ◦ tektoncd/catalog ◦ openshift/pipelines-catalog • Tekton Hub in beta! ◦ https://hub-preview.tekton.dev/
16. GENERAL DISTRIBUTION OpenShift Pipelines Architecture TEKTON CONCEPTS 16 PipelineResource Pipeline Task Task Define pipeline Run pipelines Pipeline Controllers (Tekton, ext, ...) pipeline-pod-a pipeline-pod-b PipelineRun TaskRun TaskRun pipeline-pod-c
17. Let’s Explore! Hacking away at it until it works. GitOps Happy Hour 17 Keyboard time!