hetzner

Cluster Autoscaler for Hetzner Cloud

The cluster autoscaler for Hetzner Cloud scales worker nodes.

Configuration

HCLOUD_TOKEN Required Hetzner Cloud token.

HCLOUD_CLOUD_INIT Base64 encoded Cloud Init yaml with commands to join the cluster, Sample examples/cloud-init.txt for (Kubernetes 1.20.1)

HCLOUD_IMAGE Defaults to ubuntu-20.04, @see https://docs.hetzner.cloud/#images. You can also use an image ID here (e.g. 15512617), or a label selector associated with a custom snapshot (e.g. customized_ubuntu=true). The most recent snapshot will be used in the latter case.

HCLOUD_CLUSTER_CONFIG This is the new format replacing

• HCLOUD_CLOUD_INIT
• HCLOUD_IMAGE

Base64 encoded JSON according to the following structure

{
    "imagesForArch": { // These should be the same format as HCLOUD_IMAGE
        "arm64": "", 
        "amd64": ""
    },
    "nodeConfigs": {
        "pool1": { // This equals the pool name. Required for each pool that you have
            "cloudInit": "", // HCLOUD_CLOUD_INIT make sure it isn't base64 encoded twice ;]
            "labels": {
                "node.kubernetes.io/role": "autoscaler-node"
            },
            "taints": 
            [
                {
                    "key": "node.kubernetes.io/role",
                    "value": "autoscaler-node",
                    "effect": "NoExecute"
                }
            ]
        }
    }
}

HCLOUD_NETWORK Default empty , The id or name of the network that is used in the cluster , @see https://docs.hetzner.cloud/#networks

HCLOUD_FIREWALL Default empty , The id or name of the firewall that is used in the cluster , @see https://docs.hetzner.cloud/#firewalls

HCLOUD_SSH_KEY Default empty , The id or name of SSH Key that will have access to the fresh created server, @see https://docs.hetzner.cloud/#ssh-keys

HCLOUD_PUBLIC_IPV4 Default true , Whether the server is created with a public IPv4 address or not, @see https://docs.hetzner.cloud/#primary-ips

HCLOUD_PUBLIC_IPV6 Default true , Whether the server is created with a public IPv6 address or not, @see https://docs.hetzner.cloud/#primary-ips

Node groups must be defined with the --nodes=<min-servers>:<max-servers>:<instance-type>:<region>:<name> flag.

Multiple flags will create multiple node pools. For example:

--nodes=1:10:CPX51:FSN1:pool1
--nodes=1:10:CPX51:NBG1:pool2
--nodes=1:10:CX41:NBG1:pool3

You can find a deployment sample under examples/cluster-autoscaler-run-on-master.yaml. Please be aware that you should change the values within this deployment to reflect your cluster.

Development

Make sure you're inside the cluster-autoscaler root folder.

1.) Build the cluster-autoscaler binary:

make build-in-docker

2.) Build the docker image:

docker build -t hetzner/cluster-autoscaler:dev .

3.) Push the docker image to Docker hub:

docker push hetzner/cluster-autoscaler:dev

Updating vendored hcloud-go

To update the vendored hcloud-go code, navigate to the directory and run the hack/update-vendor.sh script:

cd cluster-autoscaler/cloudprovider/hetzner
UPSTREAM_REF=v2.0.0 hack/update-vendor.sh
git add hcloud-go/