Tim Bannister
59dcd57cc9
After removing the sections of the page that are not in line with the content guide, there is little left. Edit pages that link to removed task to no longer link there. Redirect using 302 status so that there is a future opportunity to reinstate the page or something like it. - Avoid links to removed cluster management task - Broaden applicability of “Safely Drain A Node” - Add (stub) cluster upgrade task page - Add a basic page about upgrading your cluster. - Add a task page about enabling or disabling HTTP APIs
94 lines
3.2 KiB
Markdown
94 lines
3.2 KiB
Markdown
---
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title: Upgrade A Cluster
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content_type: task
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---
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<!-- overview -->
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This page provides an overview of the steps you should follow to upgrade a
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Kubernetes cluster.
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The way that you upgrade a cluster depends on how you initially deployed it
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and on any subsequent changes.
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At a high level, the steps you perform are:
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- Upgrade the {{< glossary_tooltip text="control plane" term_id="control-plane" >}}
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- Upgrade the nodes in your cluster
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- Upgrade clients such as {{< glossary_tooltip text="kubectl" term_id="kubectl" >}}
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- Adjust manifests and other resources based on the API changes that accompany the
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new Kubernetes version
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## {{% heading "prerequisites" %}}
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You must have an existing cluster. This page is about upgrading from Kubernetes
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{{< skew prevMinorVersion >}} to Kubernetes {{< skew latestVersion >}}. If your cluster
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is not currently running Kubernetes {{< skew prevMinorVersion >}} then please check
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the documentation for the version of Kubernetes that you plan to upgrade to.
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## Upgrade approaches
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### kubeadm {#upgrade-kubeadm}
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If your cluster was deployed using the `kubeadm` tool, refer to
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[Upgrading kubeadm clusters](/docs/tasks/administer-cluster/kubeadm/kubeadm-upgrade/)
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for detailed information on how to upgrade the cluster.
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Once you have upgraded the cluster, remember to
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[install the latest version of `kubectl`](/docs/tasks/tools/install-kubectl/).
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### Manual deployments
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{{< caution >}}
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These steps do not account for third-party extensions such as network and storage
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plugins.
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{{< /caution >}}
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You should manually update the control plane following this sequence:
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- etcd (all instances)
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- kube-apiserver (all control plane hosts)
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- kube-controller-manager
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- kube-scheduler
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- cloud controller manager, if you use one
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At this point you should
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[install the latest version of `kubectl`](/docs/tasks/tools/install-kubectl/).
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For each node in your cluster, [drain](/docs/tasks/administer-cluster/safely-drain-node/)
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that node and then either replace it with a new node that uses the {{< skew latestVersion >}}
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kubelet, or upgrade the kubelet on that node and bring the node back into service.
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### Other deployments {#upgrade-other}
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Refer to the documentation for your cluster deployment tool to learn the recommended set
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up steps for maintenance.
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## Post-upgrade tasks
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### Switch your cluster's storage API version
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The objects that are serialized into etcd for a cluster's internal
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representation of the Kubernetes resources active in the cluster are
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written using a particular version of the API.
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When the supported API changes, these objects may need to be rewritten
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in the newer API. Failure to do this will eventually result in resources
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that are no longer decodable or usable by the Kubernetes API server.
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For each affected object, fetch it using the latest supported API and then
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write it back also using the latest supported API.
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### Update manifests
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Upgrading to a new Kubernetes version can provide new APIs.
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You can use `kubectl convert` command to convert manifests between different API versions.
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For example:
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```shell
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kubectl convert -f pod.yaml --output-version v1
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```
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The `kubectl` tool replaces the contents of `pod.yaml` with a manifest that sets `kind` to
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Pod (unchanged), but with a revised `apiVersion`.
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