Labels

Labels are key/value pairs in the metadata of Kubernetes objects that add identifying information to the object. They do not have direct semantic implications but can be used to organize and manage resources. The stackablectl tool, the cockpit, and the Helm Charts add labels to the resources that are part of a Stacklet, and the operators add labels to the resources they create.

Resource labels added by the operators

Every resource created by a Stackable operator has a common set of labels applied. Some of these labels are recommended to use by the Kubernetes documentation. The following labels are added to resources created by our operators:

app.kubernetes.io/name - The name of the product, i.e. druid or zookeeper.
app.kubernetes.io/version - The version of the product and Stackable version, i.e. 3.3.4-stackable24.3.0
app.kubernetes.io/instance - The name of the Stacklet.
app.kubernetes.io/component - This is the role that this resource belongs to.
app.kubernetes.io/role-group - The name of the role group that a resource belongs to.
app.kubernetes.io/managed-by - Which software manages this resource? This will be the operator, i.e. kafka-operator.

also this:

stackable.tech/vendor with value Stackable.

Labels added by tools

The resources associated with an operator installation are also labeled (or can be).

stackablectl

Installing operators and releases

When installing operators and releases, stackablectl will always label the Deployment, ConfigMap, ClusterRole etc. with

stackable.tech/vendor=Stackable

Stacks and demos

When installing a stack or a demo, stackablectl adds additional labels to identify the parts of the stack or demo:

stackable-tech/stack with the value being the Stack name.
stackable-tech/demo with the value being the Demo name.
stackable.tech/managed-by=stackablectl

These labels are attached to the demo and stack manifests, which include Secret, ConfigMap or ClusterRole.

The Stacklets themselves and external dependencies are not yet labeled with the Stack or Demo that they belong to.

Helm

The Helm Charts for the Stackable operators support specifying labels in the values.yaml file. All resources deployed by the Helm Chart (Deployment, ClusterRole, Configmap, etc.) will have the labels attached when the operator is deployed. The default set of labels includes:

stackable.tech/vendor=Stackable