[](https://hex.pm/packages/libcluster_hcloud)
# ClusterHcloud
This is a [Hetzner Cloud](https://www.hetzner.de/cloud) clustering strategy for [libcluster](https://github.com/bitwalker/libcluster).
The `labels` strategy queries the [hcloud API](https://docs.hetzner.cloud/) using [HTTPoison](https://github.com/edgurgel/httpoison) and [Jason](https://github.com/michalmuskala/jason) to find nodes by given [label selectors](https://docs.hetzner.cloud/#label-selector).
## Quick example
```elixir
config :libcluster,
topologies: [
labels_example: [
strategy: Elixir.ClusterHcloud.Strategy.Labels,
config: [
hcloud_api_access_token: "xxx",
label_selector: "mylabel",
app_prefix: "app",
show_debug: false,
private_network_name: "my-network",
polling_interval: 10_000]]],
```
You can define your topologies in the location where you start the `Cluster.Supervisor` as well.
If you use the above, remember that you still have to add `Cluster.Supervisor` to the supervision tree.
You can get the configuration using `Application.get_env(:libcluster, :topologies)`.
For further details on configuration, see the [documentation](https://hexdocs.pm/libcluster_hcloud).
To practically use this on Hetzner Cloud, you need to make sure you run your
application appropriately, i.e., you have to make sure you run your nodes with
a `name` allowing for external connections. This means it has to be run with
the Erlang start parameter `--name {app_prefix}@{private_ip}` or `--name
{app_prefix}@{public_ip}`! If you are using Mix Releases, the [documentation of
mix-release](https://hexdocs.pm/mix/Mix.Tasks.Release.html) is a good read.
TL;DR e.g. for use with **mix release** you need to set the environment variables `RELEASE_DISTRIBUTION=name` and `RELEASE_NAME={app_prefix}@{private_ip|public_ip}` when running you release.
## Installation
The package can be installed by adding `libcluster_hcloud` to your list of dependencies in `mix.exs`:
```elixir
def deps do
[
{:libcluster_hcloud, "~> 0.1.0"}
]
end
```
## Acknowledgments
This package is heavily based on [libcluster_ec2](https://github.com/kyleaa/libcluster_ec2) by [kyleaa](https://github.com/kyleaa).
