Keptn allows building scalable automation for delivery and operations. Therefore, Keptn introduces and uses the following terms.
Project: A project is a structural element to maintain multiple services forming an application in stages.
Project stage: A project stage (or just stage) defines a logical space (e.g., a namespace in Kubernetes), which has a dedicated purpose for an application in a continuous delivery process. Typically a project has multipe project stages that are ordered.
Service: A service is the smallest deployable unit and is deployed in all project stages according to the order. Each service in a project follows the same task sequences.
Shipyard: A shipyard is the declarative means to divide an environment (e.g., Kubernetes cluster) into project stages and to specify task sequences for each project stage.
Sequence: A sequence declares a set of tasks for realizing a delivery or operations process. A task sequence is triggered by an external event, i.e., by a domain event. Examples for domain events are the availablity of a new artifact which should be deployed (i.e., a
new-artifact event) or the occurence of a problem (i.e., a
Task: A task is the smallest executable unit of a sequence. A task is triggered by an event.
Keptn-service: A Keptn-service is the unit executing a task. It can be responsible for executing one or many tasks and is is triggered by an event of a task.
Uniform: The uniform declares a list of Keptn-services that represents the execution plane of a Keptn installation and are required to execute the respective tasks. (Note: Currently, Keptn provides two hard-coded execution planes: (1) full - containing Keptn-services for delivery and automated operations use cases and (2) quality gates only.)
Event: An event triggers a task and contains relevant data for the respective task.
Keptn installation: A Keptn installation encloses the control plan and execution plane.
Control plane: The control plane is the minimum set of components, which are required to run a Keptn and to manage projects, stages, and services, to handle events, and to provide integration points.
Execution plane: The execution plane consists of all Keptn-services that are required to process all tasks.
Deployment: The deployment makes a built artifact (e.g., a Docker image) available for use as a service in a project stage.
Test: The test executes a set of tests (e.g., requests) against the service. The test kind (e.g., functional or performance) can be derived from the purpose of the project stage or environment.
Evaluation: The evaluation represents the quality gate of a stage by checking the SLO.
Remediation: A remediation is an action, which is executed when a problem was detected, e.g., by the monitoring solution. The remediation action should solve the problem in an automatic way.
The quality gate is a concept that allows defining SLOs, which are determined by one or many SLIs. Source
Service-Level Indicator (SLI): An SLI is a service-level indicator, which is a defined quantitative measure of some metric of the service.
Service-Level Objective (SLO): An SLO is a service-level objective, which is a target value or range of values for an SLI. A common structure for SLOs is: SLI ≤ target value, or lower bound ≤ SLI ≤ upper bound.
Service-Level Agreement (SLA): An SLA is a service-level agreement, which is an explicit or implicit contract with your users that includes consequences of meeting (or missing) the SLOs the SLA contains.