# C++ HTTP Server import { Tabs, TabsContent, TabsList, TabsTrigger } from "zudoku/ui/Tabs" {/* vale off */} This guide explains how to create and deploy a simple C++-based HTTP web server. To run this example, follow these steps: 1. Install the CLI. Use the [unikraft CLI](/cli/unikraft) or the legacy [kraft CLI](https://unikraft.org/docs/cli/install). You need a [BuildKit](https://github.com/moby/buildkit) builder. The easiest way to get one is via [Docker](https://docs.docker.com/engine/install/). Alternatively, you can also directly set up and use BuildKit, see the [quick start](https://github.com/moby/buildkit#quick-start). 2. Clone the [example repository](https://github.com/unikraft-cloud/examples) and `cd` into the `examples/httpserver-gpp13.2/` directory: ```bash git clone https://github.com/unikraft-cloud/examples cd examples/httpserver-gpp13.2/ ``` Make sure to log into Unikraft Cloud and pick a [metro](/platform/metros) close to you. This guide uses `fra` (Frankfurt, 🇩🇪): ```bash title="unikraft" unikraft login ``` ```bash title="kraft" # Set Unikraft Cloud access token export UKC_TOKEN=token # Set metro to Frankfurt, DE export UKC_METRO=fra ``` When done, invoke the following command to deploy this app on Unikraft Cloud: ```bash title="unikraft" unikraft build . --output /httpserver-gpp132:latest unikraft run --scale-to-zero policy=on,cooldown-time=1000 --metro fra -p 443:8080/tls+http -m 256M --image /httpserver-gpp132:latest ``` ```bash title="kraft" kraft cloud deploy --scale-to-zero on --scale-to-zero-cooldown 1s -p 443:8080/tls+http -M 256Mi . ``` The output shows the instance address and other details: ```ansi title="unikraft" metro: fra name: httpserver-gpp132-jzbuo uuid: b8e015fd-d006-49d5-849e-3fd497c9159a state: starting image: /httpserver-gpp132 resources: memory: 256MiB vcpus: 1 service: uuid: fd89859a-cf60-fa1f-1d43-0989a7c18b10 name: throbbing-wave-grxjih4t domains: - fqdn: throbbing-wave-grxjih4t.fra.unikraft.app networks: - uuid: 636ebc7e-bf82-d71d-5432-5445084a4308 private-ip: 10.0.6.5 mac: 12:b0:0f:20:02:9d timestamps: created: just now ``` ```ansi title="kraft" [●] Deployed successfully! │ ├───────── name: httpserver-gpp132-jzbuo ├───────── uuid: b8e015fd-d006-49d5-849e-3fd497c9159a ├──────── metro: https://api.fra.unikraft.cloud/v1 ├──────── state: starting ├─────── domain: https://throbbing-wave-grxjih4t.fra.unikraft.app ├──────── image: oci://unikraft.io//httpserver-gpp132@sha256:a58873987104b52c13b79168a2e2f1a81876ba6efacd6dbc98e996afe5c09699 ├─────── memory: 256 MiB ├────── service: throbbing-wave-grxjih4t ├─ private fqdn: httpserver-gpp132-jzbuo.internal └─── private ip: 10.0.6.5 ``` In this case, the instance name is `httpserver-gpp132-jzbuo` and the address is `https://throbbing-wave-grxjih4t.fra.unikraft.app`. They're different for each run. Use `curl` to query the Unikraft Cloud instance of the C++ HTTP web server: ```bash curl https://throbbing-wave-grxjih4t.fra.unikraft.app ``` ```text Hello, World! ``` You can list information about the instance by running: ```bash title="unikraft" unikraft instances list ``` ```bash title="kraft" kraft cloud instance list ``` ```ansi title="unikraft" METRO NAME STATE IMAGE ARGS MEMORY VCPUS FQDN CREATED fra httpserver-gpp132-jzbuo running /httpserver-gpp132 256MiB 1 throbbing-wave-grxjih4t.fra.unikraft.app 2 minutes ago ``` ```ansi title="kraft" NAME FQDN STATE STATUS IMAGE MEMORY VCPUS ARGS BOOT TIME httpserver-gpp132-jzbuo throbbing-wave-grxjih4t.fra.unikraft.app running 1 minute ago oci://unikraft.io//httpserver-gpp132@sha256:... 256 MiB 1 15.61 ms ``` When done, you can remove the instance: ```bash title="unikraft" unikraft instances delete httpserver-gpp132-jzbuo ``` ```bash title="kraft" kraft cloud instance remove httpserver-gpp132-jzbuo ``` ## Customize your app To customize the app, update the files in the repository, listed below: * `http_server.cpp`: the actual C++ HTTP server implementation * `Kraftfile`: the Unikraft Cloud specification * `Dockerfile`: the Docker-specified app filesystem Lines in the `Kraftfile` have the following roles: * `spec: v0.7`: The current `Kraftfile` specification version is `0.7`. * `runtime: base`: The Unikraft runtime kernel to use is its base one. * `rootfs`: Build the app root filesystem. `source: ./Dockerfile` means the filesystem is built using the `Dockerfile`. `type: erofs` means the filesystem type is [EROFS](https://erofs.docs.kernel.org/). * `cmd: ["/http_server"]`: Use `/http_server` as the starting command of the instance. Lines in the `Dockerfile` have the following roles: * `FROM --platform=linux/x86_64 gcc:13.2.0-bookworm AS build`: Build the filesystem from the `bookworm gcc` container image, to [create a base image](https://docs.docker.com/build/building/base-images/). * `COPY ./http_server.cpp /src/http_server.cpp`: Copy the server implementation file (`http_server.cpp`) in the Docker filesystem (in `/src/http_server.cpp`). The following options are available for customizing the app: * If you only update the implementation in the `http_server.cpp` source file, you don't need to make any other changes. * If you create any new source files, copy them into the app filesystem by using the `COPY` command in the `Dockerfile`. * More extensive changes may require extending the `Dockerfile` ([see `Dockerfile` syntax reference](https://docs.docker.com/engine/reference/builder/)). ## Learn more Use the `--help` option for detailed information on using Unikraft Cloud: ```bash title="unikraft" unikraft --help ``` ```bash title="kraft" kraft cloud --help ``` Or visit the [CLI Reference](/cli/unikraft) or the [legacy CLI Reference](/cli/kraft/overview). {/* vale on */}