Run a Perl app
In this guide we create and deploy a simple Perl-based HTTP web server. To run this example, follow these steps:
-
Install the
kraft
CLI tool and a container runtime engine, e.g. Docker. -
Clone the
examples
repository andcd
into theexamples/http-perl5.38/
directory:
git clone https://github.com/kraftcloud/examplescd examples/http-perl5.38/
Make sure to log into Unikraft Cloud by setting your token and a metro close to you.
We use fra0
(Frankfurt, 🇩🇪) in this guide:
# Set Unikraft Cloud access tokenexport UKC_TOKEN=token# Set metro to Frankfurt, DEexport UKC_METRO=fra0
When done, invoke the following command to deploy this application on Unikraft Cloud:
kraft cloud deploy -p 443:8080 -M 512 .
The output shows the instance URL and other details:
[●] Deployed successfully! │ ├────────── name: http-perl538-1p4ml ├────────── uuid: eabb0080-0065-40ff-81a8-f790f1b218ee ├───────── state: running ├─────────── url: https://cold-brook-ba71jc16.fra0.kraft.host ├───────── image: http-perl538@sha256:8c2c1f536b349c24e04ab4fec508b69f7f2349302d42a02855318ee55c12e37c ├───── boot time: 64.56 ms ├──────── memory: 512 MiB ├─────── service: cold-brook-ba71jc16 ├── private fqdn: http-perl538-1p4ml.internal ├──── private ip: 172.16.3.3 └────────── args: /usr/bin/perl /usr/src/server.pl
In this case, the instance name is http-perl538-1p4ml
and the URL is https://cold-brook-ba71jc16.fra0.kraft.host
.
They are different for each run.
Use curl
to query the Unikraft Cloud instance of the Perl-based HTTP web server:
curl https://cold-brook-ba71jc16.fra0.kraft.host
Hello, World!
At any point in time, you can list information about the instance:
kraft cloud instance list
NAME FQDN STATE CREATED AT IMAGE MEMORY ARGS BOOT TIMEhttp-perl538-1p4ml cold-brook-ba71jc16.fra0.kraft.host stopped 37 seconds ago http-perl538@sha256:8c2c1f536b349c... 512 MiB /usr/bin/perl /usr/src/server.pl 64556us
When done, you can remove the instance:
kraft cloud instance remove http-perl538-1p4ml
Customize your Application
To customize the application, update the files in the repository, listed below:
server.pl
: the actual Perl HTTP serverKraftfile
: the Unikraft Cloud specificationDockerfile
: the Docker-specified application filesystem
#!/usr/bin/perl
use warnings;use strict;
use HTTP::Daemon;use HTTP::Status;use HTTP::Response;
my $daemon = HTTP::Daemon->new( LocalAddr => '0.0.0.0', LocalPort => 8080,) or die;
while (my $client_connection = $daemon->accept) { my $request = $client_connection->get_request; my $response = HTTP::Response->new(200); $response->content("Hello, World!\n"); $client_connection->send_response($response);}
spec: v0.6
runtime: perl:5.38
rootfs: ./Dockerfile
cmd: ["/usr/bin/perl", "/usr/src/server.pl"]
FROM scratch
# Simple Perl HTTP serverCOPY ./server.pl /usr/src/server.pl
The following options are available for customizing the application:
-
If only updating the implementation in the
server.pl
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 theDockerfile
. -
If a new Perl source files is added, update the
cmd
line in theKraftfile
and replaceserver.pl
to run that file when creating the instance. -
More extensive changes may require expanding the
Dockerfile
with additionalDockerfile
commands.
Learn More
Use the --help
option for detailed information on using Unikraft Cloud:
kraft cloud --help
Or visit the CLI Reference.