Guides

.NET

In this guide we create and deploy a simple .NET-based HTTP web server. To run this example, follow these steps:

1. Install the kraft CLI tool and a container runtime engine, e.g. Docker.

2. Clone the examples repository and cd into the examples/http-dotnet8.0/ directory:

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git clone https://github.com/kraftcloud/examples
cd examples/http-dotnet8.0/

Make sure to log into Unikraft Cloud by setting your token and a metro close to you. We use fra0 (Frankfurt, 🇩🇪) in this guide:

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# Set Unikraft Cloud access token
export UKC_TOKEN=token
# Set metro to Frankfurt, DE
export UKC_METRO=fra0

When done, invoke the following command to deploy this application on Unikraft Cloud:

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kraft cloud deploy -p 443:8080 -M 512 .

The output shows the instance URL and other details:

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[●] Deployed successfully!
 │
 ├────────── name: http-dotnet80-dsmkh
 ├────────── uuid: 25459494-cb43-4009-9d05-f0996de5b7e4
 ├───────── state: starting
 ├─────────── url: cold-fog-hl98aw6q.fra0.kraft.host
 ├───────── image: http-dotnet80@sha256:4fad7453995ae96b636696e9929ee0e7376bfbbd63ab9698c1f1e02602aa2575
 ├──────── memory: 512 MiB
 ├─────── service: cold-fog-hl98aw6q
 ├── private fqdn: http-dotnet80-dsmkh.internal
 ├──── private ip: 172.16.3.1
 └────────── args: /usr/bin/app/src

In this case, the instance name is http-dotnet80-dsmkh and the URL is https://cold-fog-hl98aw6q.fra0.kraft.host. They are different for each run.

Use curl to query the Unikraft Cloud instance of the .NET-based HTTP web server:

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curl https://cold-fog-hl98aw6q.fra0.kraft.host

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Hello, World!

At any point in time, you can list information about the instance:

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kraft cloud instance list

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NAME                 FQDN                                    STATE    CREATED AT     IMAGE                                  MEMORY   ARGS                                                      BOOT TIME
http-dotnet80-dsmkh  cold-fog-hl98aw6q.fra0.kraft.host       running  2 minutes ago  http-dotnet80@sha256:4fad7453995ae...  512 MiB  /usr/bin/app/src                                          328.69 ms

When done, you can remove the instance:

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kraft cloud instance remove http-dotnet80-dsmkh

Customize your Application

To customize the application, update the files in the repository, listed below:

• SimpleHttpServer.cs: the actual .NET HTTP server
• Kraftfile: the Unikraft Cloud specification
• Dockerfile: the Docker-specified application filesystem

Lines in the Kraftfile have the following roles:

• spec: v0.6: The current Kraftfile specification version is 0.6.

• runtime: base-compat:latest: The runtime kernel to use is the base compatibility kernel.

• rootfs: ./Dockerfile: Build the application root filesystem using the Dockerfile.

• cmd:: Use as the starting command of the instance.

Lines in the Dockerfile have the following roles:

• WORKDIR /src: Use the /src directory as the working directory.

• RUN dotnet new console: Create a new dotnet project.

• RUN rm Program.cs: Remove template source code file.

• COPY ./SimpleHttpServer.cs .: Copy the source code of the HTTP server.

• RUN dotnet build .: Build dotnet project.

• FROM scratch: Build the filesystem from the scratch container image, to create a base image.

• COPY --from=build ...: Copy on the required files from the filesystem: the binary executable, the .NET framework files and the binary library files.

The following options are available for customizing the application:

• If only updating the implementation in the SimpleHttpServer.rs source file, no other change is required.

• If new files are added, these have to be copied in the application filesystem, using the COPY command in the Dockerfile.

• More extensive changes may require expanding the Dockerfile with additional Dockerfile commands.

Learn More

Use the --help option for detailed information on using Unikraft Cloud:

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kraft cloud --help

Or visit the CLI Reference.