PODs with YAML

Step-01: Kubernetes YAML Top level Objects

• Discuss about the k8s YAML top level objects
• 01-kube-base-definition.yml

apiVersion:
kind:
metadata:
  
spec:

• Pod API Objects Reference: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#pod-v1-core

Step-02: Create Simple Pod Definition using YAML

• We are going to create a very basic pod definition
• 02-pod-definition.yml

apiVersion: v1 # String
kind: Pod  # String
metadata: # Dictionary
  name: myapp-pod
  labels: # Dictionary 
    app: myapp         
spec:
  containers: # List
    - name: myapp
      image: stacksimplify/kubenginx:1.0.0
      ports:
        - containerPort: 80

• Create Pod

# Create Pod
kubectl create -f 02-pod-definition.yml
[or]
kubectl apply -f 02-pod-definition.yml

# List Pods
kubectl get pods

Step-03: Create a NodePort Service

• 03-pod-nodeport-service.yml

apiVersion: v1
kind: Service
metadata:
  name: myapp-pod-nodeport-service  # Name of the Service
spec:
  type: NodePort
  selector:
  # Loadbalance traffic across Pods matching this label selector
    app: myapp
  # Accept traffic sent to port 80    
  ports: 
    - name: http
      port: 80    # Service Port
      targetPort: 80 # Container Port
      nodePort: 31231 # NodePort

• Create NodePort Service for Pod

# Create Service
kubectl apply -f 03-pod-nodeport-service.yml

# List Service
kubectl get svc

# Get Public IP
kubectl get nodes -o wide

# Access Application
http://<WorkerNode-Public-IP>:<NodePort>
http://<WorkerNode-Public-IP>:31231

API Object References

• Pod: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#pod-v1-core
• Service: https://kubernetes.io/docs/reference/generated/kubernetes-api/v1.18/#service-v1-core

Updated API Object References

• Pod: https://kubernetes.io/docs/reference/kubernetes-api/workload-resources/pod-v1/
• Service: https://kubernetes.io/docs/reference/kubernetes-api/service-resources/service-v1/
• Kubernetes API Reference: https://kubernetes.io/docs/reference/kubernetes-api/