website/content/en/docs/reference/setup-tools/kubeadm/kubeadm-init-phase.md

---
title: kubeadm init phase
weight: 90
---
In v1.8.0, kubeadm introduced the `kubeadm alpha phase` command with the aim of making kubeadm more modular. In v1.13.0 this command graduated to `kubeadm init phase`. This modularity enables you to invoke atomic sub-steps of the bootstrap process. Hence, you can let kubeadm do some parts and fill in yourself where you need customizations.

`kubeadm init phase` is consistent with the [kubeadm init workflow](/docs/reference/setup-tools/kubeadm/kubeadm-init/#init-workflow),
and behind the scene both use the same code.

## kubeadm init phase preflight {#cmd-phase-preflight}

Using this command you can execute preflight checks on a control-plane node.

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## kubeadm init phase certs {#cmd-phase-certs}

Can be used to create all required certificates by kubeadm.

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## kubeadm init phase kubeconfig {#cmd-phase-kubeconfig}

You can create all required kubeconfig files by calling the `all` subcommand or call then individually.

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## kubeadm init phase kubelet-start {#cmd-phase-kubelet-start}

This phase will write the kubelet configuration file and environment file and then start the kubelet.

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## kubeadm init phase control-plane {#cmd-phase-control-plane}

Using this phase you can create all required static Pod files for the control plane components.

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## kubeadm init phase etcd {#cmd-phase-etcd}

Use the following phase to create a local etcd instance based on a static Pod file.

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## kubeadm init phase upload-certs {#cmd-phase-upload-certs}

Use the following phase to upload control-plane certificates to the cluster.
By default the certs and encryption key expire after two hours.

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## kubeadm init phase mark-control-plane {#cmd-phase-mark-control-plane}

Use the following phase to label and taint the node with the `node-role.kubernetes.io/master=""` key-value pair.

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## kubeadm init phase bootstrap-token {#cmd-phase-bootstrap-token}

Use the following phase to configure bootstrap tokens.

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## kubeadm init phase upload-config {#cmd-phase-upload-config}

You can use this command to upload the kubeadm configuration to your cluster.
Alternatively, you can use [kubeadm config](/docs/reference/setup-tools/kubeadm/kubeadm-config/).

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## kubeadm init phase addon {#cmd-phase-addon}

You can install all the available addons with the `all` subcommand, or
install them selectively.

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To use kube-dns instead of CoreDNS you have to pass a configuration file:

```bash
# for installing a DNS addon only
kubeadm init phase addon coredns --config=someconfig.yaml
# for creating a complete control plane node
kubeadm init --config=someconfig.yaml
# for listing or pulling images
kubeadm config images list/pull --config=someconfig.yaml
# for upgrades
kubeadm upgrade apply --config=someconfig.yaml
```

The file has to contain a [`DNS`](https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1#DNS) field in[`ClusterConfiguration`](https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1#ClusterConfiguration)
and also a type for the addon - `kube-dns` (default value is `CoreDNS`).

```yaml
apiVersion: kubeadm.k8s.io/v1beta1
kind: ClusterConfiguration
dns:
  type: "kube-dns"
```

For more details on each field in the `v1beta1` configuration you can navigate to our
[API reference pages.] (https://godoc.org/k8s.io/kubernetes/cmd/kubeadm/app/apis/kubeadm/v1beta1)

## What's next
* [kubeadm init](/docs/reference/setup-tools/kubeadm/kubeadm-init/) to bootstrap a Kubernetes control-plane node
* [kubeadm join](/docs/reference/setup-tools/kubeadm/kubeadm-join/) to connect a node to the cluster
* [kubeadm reset](/docs/reference/setup-tools/kubeadm/kubeadm-reset/) to revert any changes made to this host by `kubeadm init` or `kubeadm join`
* [kubeadm alpha](/docs/reference/setup-tools/kubeadm/kubeadm-alpha/) to try experimental functionality