Guides

Ruby

This guide explains how to create and deploy a simple Ruby-based HTTP web server. To run this example, follow these steps:

1. Install the kraft CLI tool and a container runtime engine, for example Docker.

2. Clone the examples repository and cd into the examples/http-ruby3.2/ directory:

Code(bash)
 
git clone https://github.com/kraftcloud/examples
cd examples/http-ruby3.2/

Make sure to log into Unikraft Cloud by setting your token and a metro close to you. This guide uses fra (Frankfurt, 🇩🇪):

Code(bash)
 
# 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:

Code(bash)
 
kraft cloud deploy -p 443:8080 -M 256 .

The output shows the instance address and other details:

Code(ansi)
 
[●] Deployed successfully!
 │
 ├────────── name: http-ruby32-s6l8n
 ├────────── uuid: b1ebbbc0-5efa-476c-adb6-99866773245c
 ├───────── state: running
 ├─────────── url: https://silent-resonance-1jtz5c66.fra.unikraft.app
 ├───────── image: http-ruby32@sha256:4cf3b341898e6ebff18ff2b68353ef872dded650c9d16a6f005a8fbe8a7cbb3d
 ├───── boot time: 71.19 ms
 ├──────── memory: 256 MiB
 ├─────── service: silent-resonance-1jtz5c66
 ├── private fqdn: http-ruby32-s6l8n.internal
 ├──── private ip: 172.16.3.3
 └────────── args: /usr/bin/ruby /src/server.rb

In this case, the instance name is http-ruby32-s6l8n and the address is https://silent-resonance-1jtz5c66.fra.unikraft.app. They're different for each run.

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

Code(bash)
 
curl https://silent-resonance-1jtz5c66.fra.unikraft.app

Code(text)
 
Hello, World!

You can list information about the instance by running:

Code(bash)
 
kraft cloud instance list

Code(text)
 
NAME               FQDN                                       STATE    CREATED AT      IMAGE                                                 MEMORY   ARGS                          BOOT TIME
http-ruby32-s6l8n  silent-resonance-1jtz5c66.fra.unikraft.app  running  12 minutes ago  http-ruby32@sha256:4cf3b341898e6ebff18ff2b68353ef...  256 MiB  /usr/bin/ruby /src/server.rb  71191us

When done, you can remove the instance:

Code(bash)
 
kraft cloud instance remove http-ruby32-s6l8n

Customize your app

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

• server.rb: the actual Ruby HTTP server
• Kraftfile: the Unikraft Cloud specification
• Dockerfile: the Docker-specified app filesystem

The following options are available for customizing the app:

• If you only update the implementation in the server.rb 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).

Learn more

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

Code(bash)
 
kraft cloud --help

Or visit the CLI Reference.