Adding HCloud servers

Workers#

Consider the following spec.topology.workers from a sample Cluster resource:

		apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
metadata:
  name: mycluster
spec:
  clusterNetwork:
    services:
      cidrBlocks: ["10.128.0.0/12"]
    pods:
      cidrBlocks: ["192.168.0.0/16"]
    serviceDomain: "cluster.local"
  topology:
    classRef:
      name: hetzner-apalla-1-35-v4
    version: v1.35.7
    controlPlane:
      replicas: 3
    workers:
      machineDeployments:
        - class: workeramd64hcloud
          name: md-0
          replicas: 5
          failureDomain: nbg1
          metadata:
            labels:
              node-role.kubernetes.io/backend: "true"
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cpx42
              - name: workerMachinePlacementGroupNameHcloud
                value: md-0
        - class: workeramd64hcloud
          name: md-1
          replicas: 3
          failureDomain: nbg1
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cx53
	

A machine deployment has a single machine type. Therefore, you must create a different machine deployment for each machine type you want to use. In the example above, we have three replicas of cx53 machines and five replicas of cpx42 machines.

You can define as many machine deployments as you like, and scale them separately by setting the number of replicas. It is also possible to use an autoscaler. If you are interested in doing so, please read How to Use Cluster Autoscaler .

Each machine deployment requires a unique name. This name will be reflected in the machine names in Hetzner.

If you want to assign a label to all nodes of a machine deployment, you can do so in metadata.labels:

		metadata:
  labels:
    node.cluster.x-k8s.io/foo: "bar"
    node.cluster.x-k8s.io/baz: "qux"
	

Control planes#

To set the amount of control plane nodes, change the value of spec.topology.controlPlane.replicas in your Cluster resource.

Machine types#

We support all VM types with at least 4GB RAM, shared or dedicated vCPU, including arm64 machines .

For control plane nodes, we recommend at least 4 vCPUs and 8 GB of RAM, using the CPX (Regular Performance) line. This corresponds to a CPX32 instance, though for most clusters, a CPX42 offers better performance and headroom.

Regular Performance series:

Dedicated series:

Cost-Optimized series:

ARM series (CAX) — temporarily unavailable:

Note on regions#

We only support control plane machines in the same region.

Load Balancers at Hetzner are always in a single region, so there is no real benefit to having nodes in multiple regions because there is a single point of failure in the zone of your Load Balancer. In the event of an outage, even if your nodes are distributed, access to your cluster will be halted if your Load Balancer region is affected.

Having your nodes in a single region improves latency. This is relevant since etcd is latency sensitive, so this reduction will outweigh any benefits you might get from having a multi-region cluster.