# Ruby on Rails import { Tabs, TabsContent, TabsList, TabsTrigger } from "zudoku/ui/Tabs" {/* vale off */} {/* THIS FILE WAS AUTOGENERATED FROM THE PUBLIC EXAMPLE REPOSITORY. DO NOT EDIT THIS FILE DIRECTLY. */} This guide explains how to create and deploy a [Ruby on Rails](https://rubyonrails.org/) app. 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). :::note The unikraft CLI is the current standard, while kraft is the legacy version. Choose one of the CLIs below and only run the commands associated with it for the rest of this guide. ::: 2. Clone the [`examples` repository](https://github.com/unikraft-cloud/examples) and `cd` into the `examples/ruby3.2-rails/` directory: ```bash git clone https://github.com/unikraft-cloud/examples cd examples/ruby3.2-rails/ ``` 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 /ruby32-rails:latest unikraft run --scale-to-zero policy=idle,cooldown-time=1000,stateful=true --metro fra -p 443:3000/tls+http -m 1G -e GEM_HOME=/usr/local/bundle -e BUNDLE_APP_CONFIG=/usr/local/bundle --image /ruby32-rails:latest ``` ```bash title="kraft" kraft cloud deploy --scale-to-zero idle --scale-to-zero-stateful --scale-to-zero-cooldown 1s -p 443:3000/tls+http -M 1Gi -e GEM_HOME=/usr/local/bundle -e BUNDLE_APP_CONFIG=/usr/local/bundle . ``` The output shows the instance address and other details: ```ansi title="unikraft" metro: fra name: ruby32-rails-apa93 uuid: 2f85b9db-94f8-45d2-8e38-ed9b56cb8695 state: starting image: /ruby32-rails resources: memory: 1024MiB vcpus: 1 service: uuid: 42265dab-df44-6d66-0075-fc07455178c8 name: aged-waterfall-qraz0s7d domains: - fqdn: aged-waterfall-qraz0s7d.fra.unikraft.app networks: - uuid: 7ae3414b-1d87-c831-d26a-506a4cf9ac71 private-ip: 10.0.3.3 mac: 12:b0:39:3e:b5:36 timestamps: created: just now ``` ```ansi title="kraft" [●] Deployed successfully! │ ├───────── name: ruby32-rails-apa93 ├───────── uuid: 2f85b9db-94f8-45d2-8e38-ed9b56cb8695 ├──────── metro: https://api.fra.unikraft.cloud/v1 ├──────── state: starting ├─────── domain: https://aged-waterfall-qraz0s7d.fra.unikraft.app ├──────── image: oci://unikraft.io//ruby32-rails@sha256:fdd46011408fdee05644665ad59b24115737e3fdb352169ec2f3f16a45d4f31d ├─────── memory: 1024 MiB ├────── service: aged-waterfall-qraz0s7d ├─ private fqdn: ruby32-rails-apa93.internal └─── private ip: 10.0.3.3 ``` In this case, the instance name is `ruby32-rails-apa93` and the address is `https://aged-waterfall-qraz0s7d.fra.unikraft.app`. They're different for each run. Use `curl` to query the Unikraft Cloud instance of the Python-based HTTP web server: ```bash curl https://aged-waterfall-qraz0s7d.fra.unikraft.app/hello ``` ```text [...]

Hello World

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 ruby32-rails-apa93 running /ruby32-rails 1.0GiB 1 aged-waterfall-qraz0s7d.fra.unikraft.app 2 minutes ago ``` ```ansi title="kraft" NAME FQDN STATE STATUS IMAGE MEMORY VCPUS ARGS BOOT TIME ruby32-rails-apa93 aged-waterfall-qraz0s7d.fra.unikraft.app running 2 minutes ago oci://unikraft.io//ruby32-rails@sha256:... 1.0 GiB 1 577.34 ms ``` When done, you can remove the instance: ```bash title="unikraft" unikraft instances delete ruby32-rails-apa93 ``` ```bash title="kraft" kraft cloud instance remove ruby32-rails-apa93 ``` ## Customize your app To customize the app, update the files in the repository, listed below: * `app/` and `config/`: the contents to update the Rails setup * `Kraftfile`: the Unikraft Cloud specification * `Dockerfile`: the Docker-specified app filesystem The `app/` and `config/` directories contain files that are to overwrite generated Rails files: ```bash tree app/ config/ ``` ```text app/ |-- controllers/ | `-- hello_controller.rb `-- views/ `-- hello/ `-- index.html.erb config/ |-- environments/ | `-- development.rb `-- routes.rb ``` These files add the configuration (controller, view, route) to print the `Hello, World!` message in Rails. They overwrite the generated Rails configuration to provide the app setup. Update these files, and other files, with required contents for your own app. Lines in the `Kraftfile` have the following roles: * `spec: v0.7`: The current `Kraftfile` specification version is `0.7`. * `runtime: base-compat:latest`: The runtime kernel to use is the base compatibility kernel. * `rootfs`: Build the app root filesystem. `source: ./Dockerfile` means the filesystem is built using the `Dockerfile`. `format: erofs` means the filesystem type is [EROFS](https://erofs.docs.kernel.org/). * `cmd: ["/usr/bin/ruby", "/app/bin/rails", "server", "-b", "0.0.0.0"]`: Use `/usr/bin/ruby /app/bin/rails server -b 0.0.0.0` as the starting command of the instance. Lines in the `Dockerfile` have the following roles: * The `RUN` lines install Rails and generate the default app setup for a `hello` app. * `COPY . /app/`: Copies the local files (from `app/` and `config/`) to the app, overwriting generated contents to provide the user-specified app. * `FROM scratch`: Build the filesystem from the [`scratch` container image](https://hub.docker.com/_/scratch/), to [create a base image](https://docs.docker.com/build/building/base-images/). * `COPY --from=build /app /app`: Copy the app directory to the filesystem. The following options are available for customizing the app: * If you only update the implementation in the `app/` or `config/` directories, or adding new directories or files to overwrite Rails generated files, you don't need to make any other changes. * If changing the app name, change the `hello` name in `RUN rails generate controller hello` to a new one. The file names in the `app/` and `config/` directories have to be similarly updated. * 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 */}