/cloud-native-2019

based on my Ephemeral Environments in Kubernetes talk at CloudNative London 2019

MIT LicenseMIT

Ephemeral Environments in Kubernetes

This repo is based on the talk at CloudNative London 2019: https://skillsmatter.com/skillscasts/14155-building-ephemeral-environments-for-developers-in-kubernetes

The slides are included here in pdf, and below are the details/steps to reproduce the demos (which are more likely to work than they did during the talk)

Steps taken to reproduce demo

Pre-setup (getting code & creating directories):

  • mkdir -p ~/code
  • mkdir -p ~/.armador
  • cd ~/code
  • git clone https://github.com/travelaudience/armador.git
  • git clone https://github.com/dockersamples/example-voting-app.git
  • cp -r armador/docs/example/example-app-charts/vote .

Armador (creating the env)

  • In order to build the Armador binary, requires Golang 1.12+
    • a welcome PR is a change to the CI steps to add builds to the release page ;)
  • I used minikube in the demo. Any K8s cluster should work, but if you choose minikube, the install steps are here: https://kubernetes.io/docs/tasks/tools/install-minikube/
  • Helm package manager is required for Armador. Install steps are here: https://github.com/helm/helm#install
    • during the demo, only Helm v2 is supported
  • installing amrador:
    • cd armador
    • go build -o $GOPATH/bin/armador
  • preparing cluster:
    • minikube start
    • helm init
  • setup the app to be installed:
    • cp ~/armador/docs/example/global-config.yaml ~/.armador.yaml
    • vi ~/.armador.yaml
      • change cluster section to point your cluster, in the demo this was:
cluster:
  minikube:
    contextname: minikube
  • create the env:
    • cd ~/code/vote
    • armador create jeff
  • kubectl get pods (armador changes your context to the namespace you created)
  • minikube service -n jeff vote-jeff-vote this exposes the service and loads the page in the browser (even though the context is in the jeff namespace, the minikube command needs that to be explicit)

Ksync

This follows closely with the doc here: https://github.com/travelaudience/armador/blob/master/docs/debug-in-k8s/Ksync.md And the install of ksync should be followed first: https://github.com/vapor-ware/ksync#installation

  • You need to run ksync watch in a seperate terminal session
  • mkdir -p ~/ksync/ (I find it useful to have a distinct place to keep the synced folders. This removes the "easy" hot-reload ability, but it keeps the sync process cleaner without unneeded file copying)
  • kubectl get pods -n jeff --show-labels getting the app= label of the pod(s) you want to sync
    • NOTE: there's another step that requires some deeper knowledge about the container that you want to sync. In the example I chose the vote app, which has:
     # Copy our code from the current folder to /app inside the container
 ADD . /app
    so I know that the files to change are in the /app path on the image. This then becomes the path that I want to have synced locally.
  • ksync create --selector=app=vote-jeff-vote --name=vote-jeff-vote -n jeff ~/ksync/vote-jeff-vote /app
  • vi ~/code/example-voting-app/vote/app.py (make a change from "Cats" to "Bunnies")
  • cp ~/code/example-voting-app/vote/app.py ~/ksync/vote-jeff-vote
  • you should now see the changes being applied in the ksync watch termnial, and refreshing the page should show "Bunnies"

Telepresence

Again, this section follows closely with the docs here: https://github.com/travelaudience/armador/blob/master/docs/debug-in-k8s/Telepresence.md And installing should follow the official docs: https://www.telepresence.io/reference/install

  • In the demo I used IntelliJ and imported the code to the worker app: ~/code/example-voting-app/worker
  • Add a new "Configuration" for the application, and provide the main class as worker.Worker
  • telepresence --namespace jeff --swap-deployment worker-jeff-worker --run-shell connect cluster with local env
  • In IntelliJ
    • set breakpoint in the Worker (maybe at lines 14 & 20)
    • click "Debug"
    • if all goes well, line 14 will hit the breakpoint
    • if you trigger a new vote in the frontend, then line 20 should hit when the worker detects the new vote