<Callout type="warning" title="ARM servers are temporarily not supported">

ARM-based servers are temporarily not supported. Due to significant declines in the availability and reliability of this server architecture, we can no longer recommend it. This is a temporary measure, and we will restore support once the situation improves.

If your cluster already uses ARM-based nodes, follow the [Migrate ARM servers to x86](/docs/hetzner/apalla/servers-and-nodes/provision/migrate-arm-to-x86) guide to switch to x86 nodes.

</Callout>

## Introduction

Servers with ARM processors offers cost optimization while retaining competitive performance when compared to x86 architecture servers, with greater efficiency for parallel workloads. Syself provides full [ARM support for Kubernetes nodes](/features/arm-support-kubernetes-nodes).

If your workload supports the ARM architecture, it can be a great alternative to further improve the scalability and costs of your infrastructure.

> [!NOTE]
> Currently, only hcloud nodes are supported. If you wish to use ARM in bare-metal servers, please contact our support.

## Step 1: Adding node images

ARM servers requires node images specifically built and optimized for their architecture. You need to add them to your HetznerClusterStackReleaseTemplate before using them in your clusters:

```yaml vars
apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
kind: HetznerClusterStackReleaseTemplate
metadata:
  name: hetzner-apalla-1-35
spec:
  template:
    spec:
      nodeImages:
        - controlplaneamd64hcloud
        - workeramd64hcloud

        - controlplanearm64hcloud

        - workerarm64hcloud
```

> [!TIP]
> If you want to run a full ARM cluster, you can remove the amd64 node images.

## Step 2: Using ARM nodes

Now you can add a new machine deployment with the `workerarm64hcloud` class and an ARM machine type, and set the appropriate variables if you wish to have ARM control planes:

```yaml vars
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: 3
          failureDomain: nbg1
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cpx42
        - class: workerarm64hcloud
          name: md-0
          replicas: 3
          failureDomain: nbg1
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cax31
    variables:
      - name: region
        value: nbg1

      - name: controlPlaneMachineArchHcloud
        value: arm64
      - name: controlPlaneMachineTypeHcloud

        value: cax31
```

Supported ARM machine types are:

| Type  |
| ----- |
| CAX21 |
| CAX31 |
| CAX41 |

For more information on Hetzner machine types, please visit the [Hetzner documentation](https://docs.hetzner.com/cloud/servers/overview/).