• A local machine with Docker installed.
• A Kubernetes cluster with kubectl installed and configured.
• A DockerHub account.

Create a Dockerfile in the ~/sample-app/ directory of the sample-app project with the following content:

FROM mcr.microsoft.com/dotnet/sdk:5.0 AS build-env
WORKDIR /app

COPY *.csproj ./
RUN dotnet restore

COPY . ./
RUN dotnet publish -c Release -o out

FROM mcr.microsoft.com/dotnet/aspnet:5.0
WORKDIR /app
COPY --from=build-env /app/out .
ENTRYPOINT ["dotnet", "sample-app.dll"]

This Dockerfile uses two stages to build the app. In the first stage, it restores the dependencies and builds the app, and in the second stage, it copies the built app and runs it.

Build the Docker image with a tag name of your choice:

docker build -t username/sample-app:latest .

Login to DockerHub with your DockerHub credentials:

docker login -u username

Push the Docker image to DockerHub:

docker push username/sample-app:latest

Create a deployment with two replicas and use the Docker image you just uploaded:

apiVersion: apps/v1
kind: Deployment
metadata:
  name: sample-app
spec:
  replicas: 2
  selector:
    matchLabels:
      app: sample-app
  template:
    metadata:
      labels:
        app: sample-app
    spec:
      containers:
      - name: sample-app
        image: username/sample-app:latest
        ports:
        - containerPort: 80

Create a service for load balancing across the pods:

apiVersion: v1
kind: Service
metadata:
  name: sample-app
spec:
  selector:
    app: sample-app
  ports:
  - name: http
    protocol: TCP
    port: 80
    targetPort: 80
  type: ClusterIP

Create an ingress for handling HTTP requests from outside the cluster:

apiVersion: networking.k8s.io/v1
kind: Ingress
metadata:
  name: sample-app
spec:
  ingressClassName: nginx
  rules:
  - host:
    http:
      paths:
      - path: /WeatherForecast
        pathType: Prefix
        backend:
          service:
            name: sample-app
            port:
              number: 80

After the following steps, the associated manifest file will look like the one in the kube-manifest.yaml file.

In order to apply the aforementioned manifest file, you will need to execute the subsequent command.

kubectl apply -f kube-manifest.yaml

You can verify the functionality of the application by sending a curl request to the URL provided below.

curl localhost/WeatherForecast

You can create a one-click install script to automate the deployment process. Here is an example script:

#!/bin/bash

# Clone the repository
git clone https://github.com/metinekinci/sample-app.git

cd sample-app

# Build and push the Docker image to DockerHub
docker build -t <dockerhub-username>/sample-app:latest .
docker login -u <dockerhub-username>
docker push <dockerhub-username>/sample-app:latest

# Manipulate the manifest file
sed -i 's/metinekinci/<dockerhub-username>/g' kube-manifest.yaml

# Create a Kubernetes deployment and service
kubectl apply -f kube-manifest.yaml

This script performs the following steps:

• Clones the sample-app repository.
• Builds and pushes the Docker image to DockerHub.
• The script manipulates the Kubernetes manifest file to make it available to the account of the person running the script.
• Applies the manifest file.

This documentation explained how to Dockerize a .NET Core web app and deploy it on a Kubernetes cluster with an Ingress and a Service. It also included instructions for uploading the Docker image to DockerHub and creating a one-click install script.