Ambassador Pod in Kubernetes ??

What is an Ambassador Container?

The ambassador container is a common pattern in Kubernetes and distributed systems. It acts as a proxy to provide additional functionality without modifying the main application.

Key Features ??

An ambassador container is a sidecar container that runs alongside the main application container in the same Pod, handling:

• ?? Service discovery
• ?? Load balancing
• ?? Protocol translation
• ??? Traffic routing
• ?? Logging and monitoring

Why Use an Ambassador Container? ??

1. Decoupling Application Logic from Networking ??

• Main application container stays focused on business logic
• Ambassador handles networking concerns: Service discovery Load balancing Request retries

Example Configurations ??

Basic Nginx Ambassador Pod:

apiVersion: v1
kind: Pod
metadata:
  name: ambassador-nginx
  labels:
    app: ambassador-pod
spec:
  containers:
  - name: nginx
    image: nginx:stable
    ports:
    - containerPort: 80        

Ambassador Service:

apiVersion: v1
kind: Service
metadata:
  name: ambassador-service
spec:
  selector:
    app: ambassador-pod
  ports:
  - protocol: TCP
    port: 8081
    targetPort: 80        

Ambassador Pod with HAProxy ??

apiVersion: v1
kind: Pod
metadata:
  name: ambassador-pod
spec:
  containers:
  - name: main-container
    image: radial/busyboxplus:curl
    command: ["sh", "-c", "while true; do curl localhost:8080; sleep 5; done"]
  - name: ambassador-container
    image: haproxy:2.4
    ports:
    - containerPort: 8080
    volumeMounts:
    - name: haproxy-config
      mountPath: /usr/local/etc/haproxy/haproxy.cfg
      subPath: haproxy.cfg
  volumes:
  - name: haproxy-config
    configMap:
      name: haproxy-config        

HAProxy ConfigMap ??

apiVersion: v1
kind: ConfigMap
metadata:
  name: haproxy-config
data:
  haproxy.cfg: |
    frontend ambassador
      bind *:8080
      default_backend ambassador_service_svc
    backend ambassador_service_svc
      server svc ambassador-service:8081        

Useful Commands ??

Check Services:

kubectl get svc        

Apply Configuration:

kubectl apply -f <file.yaml>        

View Resources:

kubectl get po,svc        

Check Service Details:

kubectl describe svc ambassador-service        

View Logs:

kubectl logs ambassador-pod -c main-container        

View ConfigMaps:

kubectl get configmap