Hello Kubernetes from ASPNET Core

Demonstrates deploying a Docker image of an ASPNET Core Web API to Kubernetes using Docker for Mac or Windows.

Prerequisites

1. Install .NET Core SDK
2. Install Docker for Mac or Windows
3. Enable Kubernetes in Docker
   • Docker preferences, check Enable Kubernetes
4. Install Kubernetes dashboard
   • Instructions: https://github.com/kubernetes/dashboard

   kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v1.10.1/src/deploy/recommended/kubernetes-dashboard.yaml
   

5. Create a sample user
   • Instructions: https://github.com/kubernetes/dashboard/wiki/Creating-sample-user
   • Create dashboard-adminuser.yaml file

   apiVersion: v1
   kind: ServiceAccount
   metadata:
   name: admin-user
   namespace: kube-system

   • Run: kubectl apply -f dashboard-adminuser.yaml
   • Show bearer token and copy

   kubectl -n kube-system describe secret $(kubectl -n kube-system get secret | grep admin-user | awk '{print $1}')
   

6. Show dashboard
   • Run: kubectl proxy
   • Go to: http://localhost:8001/api/v1/namespaces/kube-system/services/https:kubernetes-dashboard:/proxy/
   • Select token option and paste copied token

DotNet

1. Create directory and cd into it.
2. From terminal run: dotnet new webapi
3. Run: dotnet run .
4. Browse to: http:localhost:5000/api/values

Docker

1. Add following Dockerfile to project folder:

   FROM microsoft/dotnet:2.2-sdk-alpine AS build
   
   # Set working directory within container
   WORKDIR /app
   
   # Copy .csproj and restore as distinct layers
   COPY *.csproj ./
   RUN dotnet restore
   
   # Copy everything else and build
   COPY . ./
   RUN dotnet publish -c Release -o dist
   
   # Build runtime image
   FROM microsoft/dotnet:2.2-aspnetcore-runtime-alpine AS runtime
   COPY --from=build /app/dist ./
   ENTRYPOINT ["dotnet", "app.dll"]
   
   # docker build . -t tonysneed/aspnetapp-2.2
   # docker run -it --rm -p 8080:80 --name myapp tonysneed/aspnetapp-2.2
   

2. Run docker build . -t tonysneed/aspnetapp-2.2

3. Run docker run -it --rm -p 8080:80 --name myapp tonysneed/aspnetapp-2.2

4. Browse to http://localhost:8080/api/values

   • Press Ctrl+C to shut down

Kubernetes

1. Create a deployment

   kubectl run hello-kubernetes --image=tonysneed/aspnetapp-2.2 --image-pull-policy=IfNotPresent --port=80
   

   • View the deployment in the dashboard.
   • See logs to verify service is running:
     kubectl get pods
kubectl logs (plus pod name)

2. Expose deployment

   kubectl expose deployment hello-kubernetes --type=NodePort service "hello-kubernetes" exposed
   

   Note: You can safely ignore the following message:
   Error from server (NotFound): deployments.extensions "service" not found

   • View service: kubectl describe service hello-kubernetes
   • Copy the NodePort and browse to app (substituting port):
     http://localhost:30334/api/values

3. Scale deployment

   kubectl scale --replicas=3 deployment/hello-kubernetes
   

Tutorial: https://rominirani.com/tutorial-getting-started-with-kubernetes-with-docker-on-mac-7f58467203fd