1️⃣ Labels & Selectors in Kubernetes (Detailed Explanation) ⇒

🔹 Labels in Kubernetes

Labels in Kubernetes are key-value pairs assigned to objects like Pods, Nodes, and Services. They provide an efficient way to organize, manage, and filter resources within a cluster.

✅ Key Features of Labels:

• Labels are the mechanism you use to organize kubernetes objects.
• A label is a key-value pair without any predefined meaning that can be attached to the objects. [Name: Utsav, Class: Pods]
• Labels are similar to tags in AWS or git where you use a name to quick reference.
• so you are free to choose labels as you need it to refer an environment which is used for dev or testing or production , refer a product group like departmentA, departmentB
• Labels do not provide uniqueness (unlike names or UIDs).
• A single object can have multiple labels.
• Labels help categorize resources based on the environment, team, application, etc.
• Common use cases:
  • Grouping Pods by environment (e.g., env=development)
  • Tagging resources with a team name (e.g., team=backend)
  • Identifying workloads (e.g., app=nginx)

📌 Example of Labels in a Pod Configuration (Declarative Method):

Create a file pod5.yml and define a Pod with labels:

# Example of Labels in a Pod
kind: Pod
apiVersion: v1
metadata:
  name: delhipod
  labels:
    env: development
    class: pods
    love: devops
spec:
  containers:
    - name: c00
      image: ubuntu
      command: ["/bin/bash", "-c", "while true; do echo Hello-Bhupinder; sleep 5 ; done"]

🛠 Applying the Pod Configuration:

kubectl apply -f pod5.yml   # Deploy the pod with labels
kubectl get pods --show-labels  # Display the labels associated with the pod

🔹 Adding Labels to an Existing Pod (Imperative Method)