Skip to main content

​
Concept and Usage

Labels

Properties attached to each item (pod, deployment, etc.). Used to identify and group objects.

Selectors

Used to filter items based on their labels.

Annotations

Used to record additional information for your records, like buildVersion, author, etc. Not used for selection.
Normally, labels and selectors are used together to group and select objects.

​
Filtering with Selectors

kubectl get deployments --selector env=prod
kubectl get deployments --selector env=prod,tier=backend

​
Example Deployment

The metadata.labels field on the Deployment itself labels the Deployment object. The spec.selector.matchLabels and spec.template.metadata.labels are used to link the ReplicaSet to its Pods. 
apiVersion: apps/v1
kind: Deployment
metadata:
  name: my-sample-deployment
  labels:
    env: prod
    tier: backend
  annotations:     # Additional information (not used for selection)
    buildVersion: 1.0.0
    author: KarChun
spec:
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
        - name: my-ubuntu-app
          image: ubuntu

Build docs developers (and LLMs) love

Get started for freeTalk to us