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Guides

Perl HTTP Server

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

1. Install the CLI and a container runtime engine, for example Docker. Use the unikraft CLI or the legacy kraft CLI.

2. Clone the examples repository and cd into the examples/httpserver-perl5.42/ directory:

Code
git clone https://github.com/unikraft-cloud/examples
cd examples/httpserver-perl5.42/

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

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

The output shows the instance address and other details:

Code
[●] Deployed successfully!
 │
 ├────── name: httpserver-perl542-xue8j
 ├────── uuid: 59d08bbc-cbb7-4c6b-a2cb-847828845db9
 ├───── metro: fra
 ├───── state: running
 ├──── domain: https://fragrant-water-wau08gaw.fra.unikraft.app
 ├───── image: httpserver-perl542@sha256:af86e8f03c0d4cfd596ccfd9a9d18ea75ac68c996c9cde31f64db24dc11100fe
 ├─ boot time: 109.36 ms
 ├──── memory: 512 MiB
 ├─── service: fragrant-water-wau08gaw
 ├ private ip: 10.0.1.161
 └────── args: /usr/bin/perl /usr/src/server.pl

In this case, the instance name is httpserver-perl542-xue8j and the address is https://fragrant-water-wau08gaw.fra.unikraft.app. They're different for each run.

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

Code
curl https://fragrant-water-wau08gaw.fra.unikraft.app

Code
Hello, World!

You can list information about the instance by running:

Code
NAME                      FQDN                                      STATE    STATUS   IMAGE                                           MEMORY   VCPUS  ARGS                              BOOT TIME
httpserver-perl542-xue8j  fragrant-water-wau08gaw.fra.unikraft.app  standby  standby  httpserver-perl542@sha256:af86e8f03c0d4cfd5...  512 MiB  1      /usr/bin/perl /usr/src/server.pl  109.46 ms

When you list your instances, you might notice they show as standby. This is normal behavior and means the instance is using Unikraft Cloud's scale-to-zero feature that saves resources when there is no traffic. To check your instance is working, open two terminals and use these commands to watch the status:

It switches to "running" then back to "standby."

When done, you can remove the instance:

Customize your app

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

• server.pl: the actual Perl HTTP server implementation
• 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.pl 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:

Or visit the CLI Reference or the legacy CLI Reference.