Documentation is tailored to each Cluster Stack release. Pick the one your cluster runs.

<VersionDropdown size="lg" class="mx-auto max-w-fit my-8" />

{#if release.hasArmImages && minor !== stack.latest.minor}

## Check for ARM-based nodes

If your cluster isn't running ARM-based nodes, skip this step.
ARM is temporarily not supported on this release. If your cluster has any, the upgrade will fail unless you migrate them to x86 nodes first — see [Migrate ARM servers to x86 in your cluster](/docs/hetzner/apalla/servers-and-nodes/provision/migrate-arm-to-x86) for instructions.

{/if}

{#if minor === stack.latest.minor}

## You are here

<Callout type="important" title="Kubernetes 1.34">

You are seeing the documentation for Kubernetes <code>1.34</code> — the newest Kubernetes minor Syself Autopilot supports right now. If your cluster is already on this version, there's nothing to do.

Not on this version? Pick your cluster's actual version in the picker above to jump straight to the guide that applies to it.

</Callout>

## Not sure which Kubernetes version your cluster is on?

If you're not sure which Kubernetes version your cluster is currently on, check it directly:

<Steps>

<Step>Check in your cluster</Step>

Run these commands against the Syself Autopilot management cluster, not the workload cluster.

To check one cluster:

```console
$ kubectl get cluster <cluster-name> -n <namespace> \
  -o jsonpath='{.spec.topology.classRef.name}{"\n"}'
```

The command returns the Cluster Stack release name:

```console vars
hetzner-apalla-1-34-v10
```

The name includes the provider, stack, Kubernetes minor version, and Cluster Stack release. The final `vN` segment identifies the Cluster Stack release.

To check every cluster:

```console
$ kubectl get clusters -A \
  -o custom-columns='NAMESPACE:.metadata.namespace,CLUSTER:.metadata.name,CLUSTERSTACK:.spec.topology.classRef.name,KUBERNETES:.spec.topology.version'
```

**If the management cluster serves `cluster.x-k8s.io/v1beta1`**:

If the Syself Autopilot management cluster serves `cluster.x-k8s.io/v1beta1` instead of `v1beta2`, use `spec.topology.class` instead of `spec.topology.classRef.name`.

To check one cluster with `cluster.x-k8s.io/v1beta1`:

```console
$ kubectl get cluster <cluster-name> -n <namespace> \
  -o jsonpath='{.spec.topology.class}{"\n"}'
```

To check every cluster with `cluster.x-k8s.io/v1beta1`:

```console
$ kubectl get clusters -A \
  -o custom-columns='NAMESPACE:.metadata.namespace,CLUSTER:.metadata.name,CLUSTERSTACK:.spec.topology.class,KUBERNETES:.spec.topology.version'
```

<Step>If it doesn't match, change your version in the version picker</Step>

If it doesn't show <code>1.34</code>, switch the docs to your cluster's actual version using the picker below:

<VersionDropdown size="lg" class="max-w-fit mt-4" />

An upgrade guide scoped to that version will walk you through the upgrade path to get here.

</Steps>

## Explore further

<Card title="Inspect this release" href="/versions/{stack.latest.minor.version.replace('.', '-')}/v2#stack-contents-heading">

Exactly which components and versions <code>hetzner-apalla-1-36-v2</code> ships.

</Card>

<Card title="Versions Hub" href="/versions" banner={true} style="background-image: url(/images/version-hub-banner.png);
    background-image: image-set(url(/images/version-hub-banner.avif) type('image/avif'),
    url(/images/version-hub-banner.png) type('image/png')); min-height: 240px;
    background-size: cover; background-position: center 33%;">

Every maintained Kubernetes minor and Cluster Stack release, including <code>1.36</code>'s full history, with support windows and what changed between them.

</Card>

## Already on this Kubernetes version but want the latest Cluster Stack release for it?

See [Updating the cluster with same Kubernetes version](/docs/hetzner/apalla/clusters/upgrades/update-within-a-version) to get the latest Cluster Stack release for Kubernetes <code>1.34</code>.

{:else if upgrade.toNextMinor.length === 0 || upgrade.toNextMinor[0] !== upgrade.nextMinorEntry}

You are viewing documentation for Kubernetes <code>1.34</code>, Cluster Stack release <code>hetzner-apalla-1-34-v10</code>. To upgrade to Kubernetes <code>1.35</code>, first update your cluster to Cluster Stack release <code>hetzner-apalla-1-34-v10</code> by following this guide: [Updating the cluster with same Kubernetes version](/docs/hetzner/apalla/clusters/upgrades/update-within-a-version). Once that update is complete, return to this guide to upgrade your Kubernetes version.

Not sure which Kubernetes minor and Cluster Stack release your cluster uses? [Check the Kubernetes version and Cluster Stack](/docs/hetzner/apalla/clusters/configure/how-to-check-the-kubernetes-version-and-stack) of your cluster.

{:else}

This guide will detail the process of upgrading your cluster from Kubernetes <code>1.34</code> to <code>1.35</code>.

Not sure which Kubernetes minor and Cluster Stack release your cluster uses? [Check the Kubernetes version and Cluster Stack](/docs/hetzner/apalla/clusters/configure/how-to-check-the-kubernetes-version-and-stack) of your cluster.

## Upgrading the cluster

<Steps>

<Step>Adding a new Cluster Stack</Step>

Add a new `ClusterStack` and `HetznerClusterStackReleaseTemplate` for the newer Kubernetes minor version:

<Tabs id="autosubscribe" items={['autosubscribe: true', 'autosubscribe: false']}>

<TabItem value="autosubscribe: true">

{#if upgrade.nextMinorEntry === nextMinor?.latest}

> [!NOTE]
> The cluster manifest below uses `cluster.x-k8s.io/v1beta2`, the current default API version for CAPI core resources. See [Cluster API v1beta2](/docs/hetzner/apalla/clusters/upgrades/migrate-a-manifest-to-v1beta2) for more information.

```yaml vars title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: true
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
---
apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
kind: HetznerClusterStackReleaseTemplate
metadata:
  name: hetzner-apalla-1-35
spec:
  template:
    spec:
      nodeImages: []
```

{:else}

```yaml vars title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: true
  versions: []
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
---
apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
kind: HetznerClusterStackReleaseTemplate
metadata:
  name: hetzner-apalla-1-35
spec:
  template:
    spec:
      nodeImages: []
```

{/if}

</TabItem>

<TabItem value="autosubscribe: false">

```yaml vars title="clusterstack.yaml"
apiVersion: clusterstack.x-k8s.io/v1alpha1
kind: ClusterStack
metadata:
  name: hetzner-apalla-1-35
spec:
  provider: hetzner
  name: apalla
  kubernetesVersion: "1.35"
  channel: stable
  autoSubscribe: false
  versions: ["v4"]
  providerRef:
    name: hetzner-apalla-1-35
    kind: HetznerClusterStackReleaseTemplate
    apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
---
apiVersion: infrastructure.clusterstack.x-k8s.io/v1alpha1
kind: HetznerClusterStackReleaseTemplate
metadata:
  name: hetzner-apalla-1-35
spec:
  template:
    spec:
      nodeImages: []
```

</TabItem>

</Tabs>

Apply it to the cluster with your tool of choice.

> [!TIP]
> For versions before hetzner-apalla-1-35-v1, node images for the new version will start to build. The build process takes around 5 minutes. You can check the status of the newly created Cluster Stack object if something seems wrong.

<Step>Checking the available ClusterStackReleases</Step>

The next step is to is to check the available `ClusterStackReleases`:

{#if upgrade.nextMinorEntry === nextMinor?.latest}

```console vars
$ kubectl get clusterstackrelease
NAME                      K8S VERSION   READY   AGE   REASON   MESSAGE
hetzner-apalla-1-34-v10   v1.34.10      true    2d
hetzner-apalla-1-35-v4    v1.35.7       true    1m
```

{:else}

```console vars
$ kubectl get clusterstackrelease
NAME                      K8S VERSION   READY   AGE   REASON   MESSAGE
hetzner-apalla-1-34-v10   v1.34.10      true    2d
...                       ...           true    1m
hetzner-apalla-1-35-v4    v1.35.7       true    1m
```

{/if}

Note down the values of the `NAME` and `K8S VERSION` columns from the release you want to upgrade to.

Now we edit our cluster and change the `spec.topology.class` and `spec.topology.version` to match the `NAME` and `K8S VERSION` of our cluster stack release:

{#if upgrade.nextMinorEntry === nextMinor?.latest}

```yaml vars persistBlur title="cluster.yaml"
apiVersion: cluster.x-k8s.io/v1beta2
kind: Cluster
metadata:
  name: mycluster
spec:
  topology:
    classRef:
      name: hetzner-apalla-1-35-v4
    version: v1.35.7
    controlPlane:
      replicas: 3
    workers:
      machineDeployments:
        - class: workeramd64hcloud
          name: md-0
          replicas: 1
          failureDomain: nbg1
          variables:
            overrides:
              - name: workerMachineTypeHcloud
                value: cpx42
    variables:
      - name: region
        value: nbg1
      - name: controlPlaneMachineTypeHcloud
        value: cpx42
```

{:else}

<Timeline kubernetes="nextminor" />

{/if}

This can be achieved either by editing the resource inside the management cluster, or by updating it in your GitOps repository.

Syself now rolls the cluster to the new Kubernetes minor version, one node at a time. The control plane and the API server stay available throughout. Bare-metal control-plane and worker pools run one fewer node during each step, so size them with headroom; the [prechecks](/docs/hetzner/apalla/clusters/upgrades/plan-maintenance-and-prechecks) cover this.

When the roll finishes, confirm every node reports the new version and `Ready`, the control plane and etcd are healthy, and your workloads still serve traffic. If a rollout stalls, see [Stuck or failed upgrade](/docs/hetzner/apalla/clusters/troubleshooting/stuck-or-failed-upgrade).

If you are no longer using the old `ClusterStack` and `HetznerClusterStackReleaseTemplate` anymore, you can remove them now.

</Steps>

{/if}

> [!NOTE]
> Starting from hetzner-apalla-1-35-v1, Hetzner node image builds are no longer required. Because of that, we require a common SSH key for both bare metal and cloud servers. If you did not use the same SSH key when doing the [Hetzner account preparation](/docs/hetzner/apalla/getting-started/prepare-your-hetzner-account), please change the secrets to ensure you have a single SSH key.