#Architecture

#Tekton Operator Architecture Overview

Tekton Operator is a Kubernetes extension that installs, upgrades, and manages TektonCD components on any Kubernetes cluster. It follows the Kubernetes Operator pattern to provide lifecycle management for Tekton components.

#Core Components

#1. Custom Resource Definitions (CRDs)

Tekton Operator defines several custom resources to manage different Tekton components:

• TektonConfig: Top-level resource that orchestrates the installation of other components
• TektonPipeline: Manages the Tekton Pipelines component
• TektonTrigger: Manages the Tekton Triggers component
• TektonResult: Manages the Tekton Results component
• TektonChain: Manages the Tekton Chains component
• OpenShiftPipelinesAsCode: Manages the Pipelines as Code component

#2. Controller

The operator controller watches for changes to these custom resources and reconciles the actual state with the desired state:

• Detects changes in custom resources
• Installs or upgrades corresponding Tekton components
• Manages dependencies between components
• Handles configuration changes
• Performs health checks and error recovery

#3. Webhook

The webhook component provides validation and defaulting for the custom resources:

• Validates custom resource configurations
• Sets default values where necessary
• Prevents invalid configurations

#Workflow

1. Installation of Operator

   • Operator can be installed via Operator Hub, release files, or from source code
   • Creates necessary CRDs and RBAC permissions

2. Resource Creation

   • User creates a TektonConfig resource (or individual component resources)
   • Defines the desired state and configuration

3. Component Installation

   • Operator detects the custom resource
   • Installs the specified Tekton components
   • Configures them according to specifications

4. Lifecycle Management

   • Manages updates and upgrades
   • Handles configuration changes
   • Recovers from failures

#Deployment Architecture

#Basic Components

1. Operator Deployment

   • Contains the controller and webhook
   • Requires cluster-level permissions
   • Watches for custom resources

2. Custom Resources

   • Define the desired state
   • Store configuration
   • Represent Tekton components

#Component Relationships

The TektonConfig resource orchestrates the creation of other resources:

1. Dependency Management

   • Ensures components are installed in the correct order
   • Manages shared resources
   • Handles component interdependencies

2. Configuration Propagation

   • Passes common settings to component-specific resources
   • Ensures consistency across components

#Security Architecture

1. RBAC Permissions

   • Operator requires cluster-level permissions
   • Components use namespace-level permissions
   • Follows principle of least privilege

2. Resource Isolation

   • Components can be installed in different namespaces
   • Supports multi-tenant deployments

#Extensibility Design

1. Configuration Options
   • Extensive configuration options for each component
   • Support for custom settings and profiles

#References

• Tekton Operator Documentation
• Kubernetes Operator Pattern
• Tekton Components