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Lab 3 - Multiple Containers

Problem

This service has already been packaged into a container image, but there is one special requirement: - The legacy app is hard-coded to only serve content on port 8989, but the team wants to be able to access the service using the standard port 80.

Your task is to build a Kubernetes pod that runs this legacy container and uses the ambassador design pattern to expose access to the service on port 80.

This setup will need to meet the following specifications:

  • The pod should have the name vader-service.
  • The vader-service pod should have a container that runs the legacy vader service image: ibmcase/millennium-falcon:1.
  • The vader-service pod should have an ambassador container that runs the haproxy:1.7 image and proxies incoming traffic on port 80 to the legacy service on port 8989 (the HAProxy configuration for this is provided below).
  • Port 80 should be exposed as a containerPort.

Note: You do not need to expose port 8989

  • The HAProxy configuration should be stored in a ConfigMap called vader-service-ambassador-config.
  • The HAProxy config should be provided to the ambassador container using a volume mount that places the data from the ConfigMap in a file at /usr/local/etc/haproxy/haproxy.cfg. haproxy.cfg should contain the following configuration data:
global
    daemon
    maxconn 256

defaults
    mode http
    timeout connect 5000ms
    timeout client 50000ms
    timeout server 50000ms

listen http-in
    bind *:80
    server server1 127.0.0.1:8989 maxconn 32

Once your pod is up and running, it's a good idea to test it to make sure you can access the service from within the cluster using port 80. In order to do this, you can create a busybox pod in the cluster, and then run a command to attempt to access the service from within the busybox pod.

Create a descriptor for the busybox pod called busybox.yml

apiVersion: v1
kind: Pod
metadata:
  name: busybox
spec:
  containers:
  - name: myapp-container
    image: radial/busyboxplus:curl
    command: ['sh', '-c', 'while true; do sleep 3600; done']

Create the busybox testing pod. 

kubectl apply -f busybox.yml

Use this command to access vader-service using port 80 from within the busybox pod. 

kubectl exec busybox -- curl $(kubectl get pod vader-service -o=custom-columns=IP:.status.podIP --no-headers):80

If the service is working, you should get a message that the hyper drive of the millennium falcon needs repair.

Relevant Documentation: - Kubernetes Sidecar Logging Agent - Shared Volumes - Distributed System Toolkit Patterns