Ambassador API Gateway

This is Kubernetes-native API Gateway for controlling and managing traffic between microservices within a Kubernetes cluster. Built on top of Envoy Proxy.
It integrates with Kubernetes Service objects to route traffic to the appropriate microservices based on the service name and port.
Advatanges:
1. Supports Multiple Protocols: HTTP/1.1, HTTP/2, WebSocket, gRPC, and OpenAPI/Swagger
2. Other Functions: traffic splitting, load balancing, rate limiting, and authentication.

Namespace

Namespace divides cluster into smaller units to isolate services,volumes and manage.
Namespace contains pods.
3 predefined namespaces: Default, Kube-system(resources created by kubernets), Kube-public(reserved for future)

$ kubectl create namespace test                       //Creating new namespace
$ kubectl --namespace=test  run ngnix --image=nginx   //Deploy namespace
            

Nodeport

When we create a NodePort service in Kubernetes, Kubernetes will dynamically allocate a port (in the range of 30000-32767) for a Application running container. Eg:30001
Then this port=30001 is mapped to targetPort=8080 internally.
Why NodePort? 2 Applications can use same internal ports. Eg: App1 uses 8080 & App2 uses 8080. And with NodePort both can be accessed using external port without port change on application level.

apiVersion: v1
kind: Service
metadata:
    name: jams-server         //Application using Nodeport. Kubernets will assign an IP=30001
spec:
    selector:
    app: my-app             //Run application on pods with Label = my-app
    type: NodePort
    ports:
    - protocol: TCP
        port: 80
        targetPort: 8080      //30001 is mapped to 8080 internally.
            

Authorization in kubernets