thenaim/httpenv repository overview

A very simple image serving environment variables over HTTP. I use this image to test kubernetes ClusterIP service.

⁠Quick Start

⁠Docker

• Run docker container and expose port

  docker run --rm -p8888:8888 thenaim/httpenv
  

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• Test endpoint

  curl http://localhost:8888
  
  curl http://localhost:8888/blue
  
  curl http://localhost:8888/green
  
  curl http://localhost:8888/red
  

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⁠Kubernetes

⁠Create deployment and service

• In another window, watch the pods (to see when they are created):

  kubectl get pods -w
  

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• Create a deployment for this very lightweight HTTP server:

  kubectl create deployment httpenv --image=thenaim/httpenv
  

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• Scale it to 10 replicas:

  kubectl scale deployment httpenv --replicas=10
  

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• Expose the HTTP port of our server. We'll create a default ClusterIP service

  kubectl expose deployment httpenv --port 8888
  

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• Look up which IP address was allocated:

  kubectl get service
  

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---

⁠Test endpoint

• Let's obtain the IP address that was allocated for our service:

  IP=$(kubectl get svc httpenv -o go-template --template '{{ .spec.clusterIP }}')
  

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• Generate URL

  echo http://$IP:8888/
  

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• Run Busybox to access ClusterIP

  kubectl run busybox --image=radial/busyboxplus:curl -i --tty
  

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• Send a few requests:

  curl http://$IP:8888/
  

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• Too much output? Filter it with jq:

  curl -s http://$IP:8888/ | jq .HOSTNAME
  

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• Others

  curl http://$IP:8888/blue
  
  curl http://$IP:8888/green
  
  curl http://$IP:8888/red
  

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