Running Flatcar on Brightbox
These instructions will walk you through using Flatcar on Brightbox, importing a custom image, and running your first server using the command line interface. Please note that Brightbox is compatible with OpenStack: it is not a mistake if we refer to OpenStack images and specific variables.
Import the image
While Brightbox provides Flatcar images for Beta, Stable and LTS channels it is possible to import your own Flatcar image in Brightbox using the CLI .
For example, to upload an image from the Flatcar Alpha channel:
$ brightbox images register \
--arch=x86_64 --name=flatcar-alpha \
--url=https://alpha.release.flatcar-linux.net/amd64-usr/current/flatcar_production_openstack_image.img
$ brightbox images list --type=upload
id owner type created_on status size name
---------------------------------------------------------------------------------
img-xoufd acc-jg5aa upload 2023-12-05 private 8694 flatcar-alpha (x86_64)
---------------------------------------------------------------------------------
Butane Configs
Flatcar allows you to configure machine parameters, launch systemd units on startup and more via Butane Configs. These configs are then transpiled into Ignition JSON configs and given to booting machines. Jump over to the docs to learn about the supported features . We’re going to provide our Butane Config to Brightbox via the user-data flag. Our Butane Config will also contain SSH keys that will be used to connect to the instance.
As an example, this Butane YAML config will start an Nginx Docker container and display the instance hostname:
variant: flatcar
version: 1.0.0
passwd:
users:
- name: core
ssh_authorized_keys:
- ssh-rsa ABCD...
storage:
directories:
- path: /var/www
systemd:
units:
- name: nginx.service
enabled: true
contents: |
[Unit]
Description=NGINX example
After=docker.service coreos-metadata.service
Requires=docker.service coreos-metadata.service
[Service]
EnvironmentFile=/run/metadata/flatcar
TimeoutStartSec=0
ExecStartPre=-/usr/bin/docker rm --force nginx1
ExecStartPre=-/usr/bin/bash -c "echo 'Hello from ${COREOS_OPENSTACK_HOSTNAME}' > /var/www/index.html"
ExecStart=/usr/bin/docker run --name nginx1 --volume "/var/www:/usr/share/nginx/html:ro" --pull always --log-driver=journald --net host docker.io/nginx:1
ExecStop=/usr/bin/docker stop nginx1
Restart=always
RestartSec=5s
[Install]
WantedBy=multi-user.target
Transpile it to Ignition JSON:
cat butane.yaml | docker run --rm -i quay.io/coreos/butane:release > ignition.json
The coreos-metadata.service
saves metadata variables to /run/metadata/flatcar
. Systemd units can use them with EnvironmentFile=/run/metadata/flatcar
in the [Service]
section when setting Requires=coreos-metadata.service
and After=coreos-metadata.service
in the [Unit]
section.
Launch machine
Boot the machines with the CLI, referencing the image ID from the import step above or using an official image ID (brightbox images list --type=official
) and your
Ignition file from Butane
:
$ brightbox servers create --cloud-ip=true --user-data-file=./ignition.json img-xoufd
Your first Flatcar instance should now be running. The only thing left to do is find the IP address and SSH in.
$ brightbox servers show $THE_INSTANCE_ID
...
cloud_ipv4s: 109.107.37.145
...
Finally SSH into an instance, note that the user is core
:
$ curl 109.107.37.145
Hello from srv-f0lo3.gb1.brightbox.com
$ ssh [email protected]
core@srv-f0lo3 ~ $ systemctl status nginx
● nginx.service - NGINX example
Loaded: loaded (/etc/systemd/system/nginx.service; enabled; preset: enabled)
Active: active (running) since Tue 2023-12-05 16:25:06 UTC; 1min 53s ago
...
⚠️ In the following example, the default firewall policy created during account registration has been used, which permits access to TCP ports 22 and 80. If you’ve modified the default firewall policy then you may need to take additional steps to open access. Here’s the documentation to update the firewall policies: https://www.brightbox.com/docs/guides/cli/firewall/
Using Flatcar Container Linux
Now that you have a machine booted it is time to play around. Check out the Flatcar Container Linux Quickstart guide or dig into more specific topics .