Update KubernetesIngress docker builds (dotnet#2446)

Author: benjaminpetit

samples/KubernetesIngress.Sample/Combined/Dockerfile

@@ -1,12 +1,13 @@
 #See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
 WORKDIR /app
 EXPOSE 80
 EXPOSE 443
 
-FROM amd64/buildpack-deps:jammy-curl AS publish
+FROM mcr.microsoft.com/dotnet/sdk:8.0  AS publish
 WORKDIR /src
+# We need to install the SDK manually because we might target an unreleased SDK
 COPY ["global.json", ""]
 RUN curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --jsonfile global.json
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT 1
@@ -28,7 +29,7 @@ WORKDIR /src
 COPY . .
 
 WORKDIR /src/samples/KubernetesIngress.Sample/Combined/
-RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net6.0
+RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net8.0
 
 FROM base AS final
 WORKDIR /app

samples/KubernetesIngress.Sample/Ingress/Dockerfile

@@ -1,12 +1,13 @@
 #See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
 WORKDIR /app
 EXPOSE 80
 EXPOSE 443
 
-FROM amd64/buildpack-deps:jammy-curl AS publish
+FROM mcr.microsoft.com/dotnet/sdk:8.0  AS publish
 WORKDIR /src
+# We need to install the SDK manually because we might target an unreleased SDK
 COPY ["global.json", ""]
 RUN curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --jsonfile global.json
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT 1
@@ -28,7 +29,7 @@ WORKDIR /src
 COPY . .
 
 WORKDIR /src/samples/KubernetesIngress.Sample/Ingress/
-RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net6.0
+RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net8.0
 
 FROM base AS final
 WORKDIR /app

samples/KubernetesIngress.Sample/Monitor/Dockerfile

@@ -1,12 +1,13 @@
 #See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
 WORKDIR /app
 EXPOSE 80
 EXPOSE 443
 
-FROM amd64/buildpack-deps:jammy-curl AS publish
+FROM mcr.microsoft.com/dotnet/sdk:8.0  AS publish
 WORKDIR /src
+# We need to install the SDK manually because we might target an unreleased SDK
 COPY ["global.json", ""]
 RUN curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --jsonfile global.json
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT 1
@@ -28,7 +29,7 @@ WORKDIR /src
 COPY . .
 
 WORKDIR /src/samples/KubernetesIngress.Sample/Monitor/
-RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net6.0
+RUN /root/.dotnet/dotnet publish -c Release --no-restore -o /app/publish -f net8.0
 
 FROM base AS final
 WORKDIR /app

samples/KubernetesIngress.Sample/backend/Dockerfile

@@ -1,20 +1,21 @@
 #See https://aka.ms/containerfastmode to understand how Visual Studio uses this Dockerfile to build your images for faster debugging.
 
-FROM mcr.microsoft.com/dotnet/aspnet:6.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:8.0 AS base
 WORKDIR /app
 EXPOSE 80
 EXPOSE 443
 
-FROM amd64/buildpack-deps:jammy-curl AS publish
+FROM mcr.microsoft.com/dotnet/sdk:8.0  AS publish
 WORKDIR /src
+# We need to install the SDK manually because we might target an unreleased SDK
 COPY ["global.json", ""]
 RUN curl -sSL https://dot.net/v1/dotnet-install.sh | bash /dev/stdin --jsonfile global.json
 ENV DOTNET_SYSTEM_GLOBALIZATION_INVARIANT 1
 
 COPY ["samples/KubernetesIngress.Sample/backend", "backend"]
 
 WORKDIR /src/backend
-RUN /root/.dotnet/dotnet publish -c Release -o /app/publish -f net6.0
+RUN /root/.dotnet/dotnet publish -c Release -o /app/publish -f net8.0
 
 FROM base AS final
 WORKDIR /app