https://github.com/thor77/hetzner-flatcar
A tool to deploy Flatcar Linux on Hetzner Cloud
https://github.com/thor77/hetzner-flatcar
flatcar-linux hetzner-cloud
Last synced: 3 days ago
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A tool to deploy Flatcar Linux on Hetzner Cloud
- Host: GitHub
- URL: https://github.com/thor77/hetzner-flatcar
- Owner: Thor77
- License: mit
- Created: 2022-04-18T13:33:25.000Z (about 3 years ago)
- Default Branch: master
- Last Pushed: 2025-04-16T22:57:38.000Z (2 months ago)
- Last Synced: 2025-06-19T05:04:49.612Z (3 days ago)
- Topics: flatcar-linux, hetzner-cloud
- Language: Go
- Homepage:
- Size: 114 KB
- Stars: 4
- Watchers: 1
- Forks: 1
- Open Issues: 7
-
Metadata Files:
- Readme: README.md
- License: LICENSE
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README
# hetzner-flatcar
A tool to deploy [Flatcar Linux](https://flatcar.org/) on [Hetzner Cloud](https://www.hetzner.com/cloud/).
Includes transpiling of [Container Linux Config](https://www.flatcar.org/docs/latest/provisioning/cl-config/) and reinstalling maschines on changes.
## Build
`go build .`
## Usage
* create a config named `config.toml` with the values described in [configuration](#configuration).
* create a container linux config template, see [template](#template) for details
* `./hetzner-flatcar hostname`
This tool will establish a SSH session to the rescue os to run the flatcar-install script using [goph](https://github.com/melbahja/goph).
For authentication it uses the SSH agent, so ensure the private counterpart to the public key uploaded to Hetzner and referenced in the config is added to your SSH agent.
## Configuration
```toml
[hcloud]
token = ""
server_type = "cx11"
location = "nbg1"
ssh_key = ""
private_network = ""
[flatcar]
version = "3139.2.0"
config_template = "ignition.yml.gtpl"
# provide path to custom flatcar-install script
# if not provided will be downloaded from
# https://github.com/flatcar-linux/init/blob/flatcar-master/bin/flatcar-install
# install_script = "custom-install-script"
[flatcar.template_static]
nomad_version = "1.2.6"
consul_version = "1.11.4"
```
## Template
The [Container Linux Config](https://github.com/flatcar-linux/container-linux-config-transpiler/blob/flatcar-master/doc/configuration.md) template is rendered using [text/template](https://golang.org/pkg/text/template/) and is given this data:
* `Server` - [Server](https://pkg.go.dev/github.com/hetznercloud/hcloud-go/hcloud#Server) object as returned by Hetzner Cloud API
* `SSHKey` - [SSHKey](https://pkg.go.dev/github.com/hetznercloud/hcloud-go/hcloud#SSHKey) object of the SSH Key used for rescue boot
* `Static` - static data from [config](#configuration) option `flatcar.template_static` as `map[string]string`
* `ReadFile(filename string) (string, error)` - function to read a local file
* `Function(indent int, input string) string` - function to indent strings
Afterwards it's transpiled into a Ignition file.
Take a look at the [example config](doc/example.yml.gtpl) for a minimal example just creating a `core` user with the SSH Key used for rescue boot and setting the hostname to the maschine name.
### injecting local files
The container linux config transpiler supports injecting local files ([ref](https://github.com/flatcar-linux/container-linux-config-transpiler/blob/flatcar-master/config/types/files.go#L177)).
Unfortunately that feature is not usable when not calling it using the CLI, because it relies on the value of a flag to determine the base path to search for files.
As an alternative hetzner-flatcar supports the `ReadFile` template function to inject files into templates.
Example usage:
```
storage:
files:
- path: /etc/LICENSE
filesystem: root
contents:
inline: |
{{ call .ReadFile "LICENSE" | call .Indent 12 }}
```
### Custom template command
Instead of using the native go template, you can also use any other command (for example [Helm](https://helm.sh)).
To do that provide your custom command in the configuration option `flatcar.template_command`.
It will get passed the hostname as the first argument and `Server` and `SSHKey` in YAML format on stdin.
```
hetzner:
server:
name: ...
sshkey:
publickey: ...
```
Example script to render a helm template with a values file based on the hostname:
```sh
#!/bin/sh
cat - common.yaml "${1}.yaml" | yq -y . | helm template ignition -f -
```
## Deployment procedure
1. check whether vm with the name given as first parameter already exists
2. create VM (if not already exists)
3. render container linux config template with data from new or existing VM
4. transpile container linux config into ignition file
5. enable rescue boot on VM
6. Startup or reboot VM (into rescue)
7. upload flatcar-install script and rendered ignition config
8. call flatcar-install and reboot