KubeVela Documentation

Workflows in KubeVela allow developers to customize the delivery process beyond the standard Kubernetes 'Apply' model. They can be used to implement complex logic such as manual approvals, conditional execution, multi-environment gray releases, and A/B testing.

Key capabilities include:

• Built-in Steps: Use predefined steps like suspend, notification, deploy, and step-group.
• Custom Steps: Define your own WorkflowStepDefinition if built-in steps are insufficient.
• Automatic Workflows: If no workflow is explicitly declared in an Application, KubeVela automatically generates a default workflow to deploy the components.

Module hooks are lifecycle actions declared in module.yaml and executed by vela def apply-module. They allow platform engineers to prepare a cluster before definitions (ComponentDefinitions and TraitDefinitions) are applied and verify the state after they land.

Common use cases include:

• Ensuring a target namespace exists and is labeled.
• Registering required CRDs before a trait patches them.
• Creating secrets or ConfigMaps for credentials.
• Running smoke tests after application to confirm definitions are visible.

Important: Module application is not atomic. There is no rollback; if a definition fails during apply, post-apply hooks still run, and failures in post-apply hooks do not remove already-applied definitions.

OAM Definitions are the building blocks of the KubeVela platform. They encapsulate complex automation as modular components that can be shared and discovered to compose an Application. There are four primary types of definitions:

• ComponentDefinition: Defines the basic building blocks of an application.
• TraitDefinition: Defines optional capabilities that can be added to components.
• PolicyDefinition: Defines how applications are deployed and managed.
• WorkflowStepDefinition: Defines steps within an application delivery workflow.