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Resources labelling

Tekton applications sometimes need to find resources belonging to other applications (dashboard needs to talk to pipelines and triggers, triggers needs to talk to pipelines, etc.).

In order to facilitate identifying resources that belong to an application, the following recommended labels are added to every resource.

In the end, resource labels are used for two things:

  • Identify the application and/or component resources belong to
  • Allow looking up the resource when necessary

The labels set should not cover more than what is needed, for example, if the resource is not to be looked up, it's probably not necessary to set the app.kubernetes.io/name label.

Supported labels

  • app.kubernetes.io/part-of: defines the application the resource belongs to (tekton-pipelines, tekton-dashboard, tekton-triggers, etc).
  • app.kubernetes.io/component: defines the component the resource belongs to (controller, webhook). This label is not always present, an application may not be made of multiple components or the resource may not belong to a specific component of the application. This label should be present only if the resource belongs to a given component (some resources are )
  • app.kubernetes.io/instance: defines the instance of the application the resource belongs to. This label should always be set. It is particularly useful when multiple instances of an application are deployed in the same cluster/namespace.
  • app.kubernetes.io/name: this label should uniquely identify a resource when combined with app.kubernetes.io/part-of, app.kubernetes.io/component and app.kubernetes.io/instance labels. Some resources don't need to be looked up, in this case the app.kubernetes.io/name label is not necessary.
  • app.kubernetes.io/version: defines the version for the resource.

Looking up resources

Looking up a given resource should not rely on resource names but use the previously documented labels.

For example, if Tekton Pipelines was deployed in the tekton-pipelines namespace, and you need to lookup the webhook service. This should be done by looking up the Service in the tekton-pipelines namespace that matches the following labels:

label value
app.kubernetes.io/part-of tekton-pipelines
app.kubernetes.io/component webhook
app.kubernetes.io/instance default
app.kubernetes.io/name webhook

Equivalent kubectl command:

kubectl --namespace=tekton-pipelines get svc -l "app.kubernetes.io/part-of=tekton-pipelines,app.kubernetes.io/component=webhook,app.kubernetes.io/instance=default,app.kubernetes.io/name=webhook"

See below for the list of applications, components, and names for most commonly used resources.

Reference table

The table below lists applications, components, and names for most commonly used resources.

resource type app.kubernetes.io/part-of app.kubernetes.io/component app.kubernetes.io/name
pipelines controller deployment Deployment tekton-pipelines controller controller
pipelines controller service Service tekton-pipelines controller controller
pipelines webhook service Service tekton-pipelines webhook webhook
triggers controller deployment Deployment tekton-triggers controller controller
triggers controller service Service tekton-triggers controller controller
triggers webhook service Service tekton-triggers webhook webhook
dashboard controller deployment Deployment tekton-dashboard dashboard dashboard
dashboard controller service Service tekton-dashboard dashboard dashboard

NOTE: the app.kubernetes.io/instance label is set to default when deployed with yaml manifests provided in the releases.