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Add `kubeadm upgrade` docs
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| --- | ||
| approvers: | ||
| - pipejakob | ||
| - luxas | ||
| - roberthbailey | ||
| - jbeda | ||
| title: Upgrading kubeadm clusters from 1.7 to 1.8 | ||
| --- | ||
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| {% capture overview %} | ||
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| This guide is for upgrading `kubeadm` clusters from version 1.7.x to 1.8.x, as well as 1.7.x to 1.7.y and 1.8.x to 1.8.y where `y > x`. | ||
| See also [upgrading kubeadm clusters from 1.6 to 1.7](/docs/tasks/administer-cluster/kubeadm-upgrade-1-7/) if you're on a 1.6 cluster currently. | ||
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| {% endcapture %} | ||
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| {% capture prerequisites %} | ||
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| Before proceeding: | ||
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| - You need to have a functional `kubeadm` Kubernetes cluster running version 1.7.0 or higher in order to use the process described here. | ||
| - Make sure you read the [release notes](https://github.com/kubernetes/kubernetes/blob/master/CHANGELOG.md#v180-beta1) carefully. | ||
| - As `kubeadm upgrade` does not upgrade etcd make sure to back it up. You can, for example, use `etcdctl backup` to take care of this. | ||
| - Note that `kubeadm upgrade` will not touch any of your workloads, only Kubernetes-internal components. As a best-practice you should back up what's important to you. For example, any app-level state, such as a database an app might depend on (like MySQL or MongoDB) must be backed up beforehand. | ||
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| Also, note that only one minor version upgrade is supported. That is, you can only upgrade from, say 1.7 to 1.8, not from 1.7 to 1.9. | ||
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| {% endcapture %} | ||
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| {% capture steps %} | ||
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| ## Upgrading your control plane | ||
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| You have to carry out the following steps by executing these commands on your master node: | ||
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| 1. Install the most recent version of `kubeadm` using `curl` like so: | ||
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| ```shell | ||
| $ export VERSION=v1.8.0 # or any given released Kubernetes version | ||
| $ export ARCH=amd64 # or: arm, arm64, ppc64le, s390x | ||
| $ curl -sSL https://dl.k8s.io/release/${VERSION}/bin/linux/${ARCH}/kubeadm > /usr/bin/kubeadm | ||
| ``` | ||
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| 2. If this the first time you use `kubeadm upgrade`, in order to preserve the configuration for future upgrades, do: | ||
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| Note that for below you will need to recall what CLI args you passed to `kubeadm init` the first time. | ||
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| If you used flags, do: | ||
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| ```shell | ||
| $ kubeadm config upload from-flags [flags] | ||
| ``` | ||
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| Where `flags` can be empty. | ||
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| If you used a config file, do: | ||
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| ```shell | ||
| $ kubeadm config upload from-file --config [config] | ||
| ``` | ||
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| Where the `config` is mandatory. | ||
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| 3. On the master node, run the following: | ||
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| ```shell | ||
| $ kubeadm upgrade plan | ||
| [preflight] Running pre-flight checks | ||
| [upgrade] Making sure the cluster is healthy: | ||
| [upgrade/health] Checking API Server health: Healthy | ||
| [upgrade/health] Checking Node health: All Nodes are healthy | ||
| [upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk | ||
| [upgrade/config] Making sure the configuration is correct: | ||
| [upgrade/config] Reading configuration from the cluster... | ||
| [upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml' | ||
| [upgrade] Fetching available versions to upgrade to: | ||
| [upgrade/versions] Cluster version: v1.7.1 | ||
| [upgrade/versions] kubeadm version: v1.8.0 | ||
| [upgrade/versions] Latest stable version: v1.8.0 | ||
| [upgrade/versions] Latest version in the v1.7 series: v1.7.6 | ||
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| Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply': | ||
| COMPONENT CURRENT AVAILABLE | ||
| Kubelet 1 x v1.7.1 v1.7.6 | ||
| Upgrade to the latest version in the v1.7 series: | ||
| COMPONENT CURRENT AVAILABLE | ||
| API Server v1.7.1 v1.7.6 | ||
| Controller Manager v1.7.1 v1.7.6 | ||
| Scheduler v1.7.1 v1.7.6 | ||
| Kube Proxy v1.7.1 v1.7.6 | ||
| Kube DNS 1.14.4 1.14.4 | ||
| You can now apply the upgrade by executing the following command: | ||
| kubeadm upgrade apply v1.7.6 | ||
| _____________________________________________________________________ | ||
| Components that must be upgraded manually after you've upgraded the control plane with 'kubeadm upgrade apply': | ||
| COMPONENT CURRENT AVAILABLE | ||
| Kubelet 1 x v1.7.1 v1.8.0 | ||
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| Upgrade to the latest experimental version: | ||
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| COMPONENT CURRENT AVAILABLE | ||
| API Server v1.7.1 v1.8.0 | ||
| Controller Manager v1.7.1 v1.8.0 | ||
| Scheduler v1.7.1 v1.8.0 | ||
| Kube Proxy v1.7.1 v1.8.0 | ||
| Kube DNS 1.14.4 1.14.4 | ||
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| You can now apply the upgrade by executing the following command: | ||
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| kubeadm upgrade apply v1.8.0 | ||
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| Note: Before you do can perform this upgrade, you have to update kubeadm to v1.8.0 | ||
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| _____________________________________________________________________ | ||
| ``` | ||
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| The `kubeadm upgrade plan` checks that your cluster is in an upgradeable state and fetches the versions available to upgrade to in an user-friendly way. | ||
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| 4. Pick a version to upgrade to and run, for example, `kubeadm upgrade apply` as follows: | ||
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| ```shell | ||
| $ kubeadm upgrade apply v1.8.0 | ||
| [preflight] Running pre-flight checks | ||
| [upgrade] Making sure the cluster is healthy: | ||
| [upgrade/health] Checking API Server health: Healthy | ||
| [upgrade/health] Checking Node health: All Nodes are healthy | ||
| [upgrade/health] Checking Static Pod manifests exists on disk: All manifests exist on disk | ||
| [upgrade/config] Making sure the configuration is correct: | ||
| [upgrade/config] Reading configuration from the cluster... | ||
| [upgrade/config] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml' | ||
| [upgrade/version] You have chosen to upgrade to version "v1.8.0" | ||
| [upgrade/versions] Cluster version: v1.7.1 | ||
| [upgrade/versions] kubeadm version: v1.8.0 | ||
| [upgrade/prepull] Will prepull images for components [kube-apiserver kube-controller-manager kube-scheduler] | ||
| [upgrade/prepull] Prepulling image for component kube-scheduler. | ||
| [upgrade/prepull] Prepulling image for component kube-apiserver. | ||
| [upgrade/prepull] Prepulling image for component kube-controller-manager. | ||
| [apiclient] Found 0 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler | ||
| [apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-scheduler | ||
| [apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-apiserver | ||
| [apiclient] Found 1 Pods for label selector k8s-app=upgrade-prepull-kube-controller-manager | ||
| [upgrade/prepull] Prepulled image for component kube-apiserver. | ||
| [upgrade/prepull] Prepulled image for component kube-controller-manager. | ||
| [upgrade/prepull] Prepulled image for component kube-scheduler. | ||
| [upgrade/prepull] Successfully prepulled the images for all the control plane components | ||
| [upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.8.0"... | ||
| [upgrade/staticpods] Writing upgraded Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769" | ||
| [controlplane] Wrote Static Pod manifest for component kube-apiserver to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-apiserver.yaml" | ||
| [controlplane] Wrote Static Pod manifest for component kube-controller-manager to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-controller-manager.yaml" | ||
| [controlplane] Wrote Static Pod manifest for component kube-scheduler to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests432902769/kube-scheduler.yaml" | ||
| [upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-apiserver.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-apiserver.yaml" | ||
| [upgrade/staticpods] Waiting for the kubelet to restart the component | ||
| [apiclient] Found 1 Pods for label selector component=kube-apiserver | ||
| [upgrade/staticpods] Component "kube-apiserver" upgraded successfully! | ||
| [upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-controller-manager.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-controller-manager.yaml" | ||
| [upgrade/staticpods] Waiting for the kubelet to restart the component | ||
| [apiclient] Found 1 Pods for label selector component=kube-controller-manager | ||
| [upgrade/staticpods] Component "kube-controller-manager" upgraded successfully! | ||
| [upgrade/staticpods] Moved upgraded manifest to "/etc/kubernetes/manifests/kube-scheduler.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests155856668/kube-scheduler.yaml" | ||
| [upgrade/staticpods] Waiting for the kubelet to restart the component | ||
| [apiclient] Found 1 Pods for label selector component=kube-scheduler | ||
| [upgrade/staticpods] Component "kube-scheduler" upgraded successfully! | ||
| [uploadconfig] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace | ||
| [bootstraptoken] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials | ||
| [bootstraptoken] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token | ||
| [addons] Applied essential addon: kube-dns | ||
| [addons] Applied essential addon: kube-proxy | ||
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| [upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.8.0". Enjoy! | ||
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| [upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets in turn. | ||
| ``` | ||
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| `kubeadm upgrade apply` does the following: | ||
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| - It checks that your cluster is in an upgradeable state, that is: | ||
| - The API Server is reachable, | ||
| - All nodes are in the `Ready` state, and | ||
| - The control plane is healthy | ||
| - It enforces the version skew policies. | ||
| - It makes sure the control plane images are available or available to pull to the machine. | ||
| - It upgrades the control plane components or rollbacks if any of them fails to come up. | ||
| - It applies the new `kube-dns` and `kube-proxy` manifests and enforces that all necessary RBAC rules are created. | ||
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| 5. Manually upgrade your Software Defined Network (SDN). | ||
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| Your Container Network Interface (CNI) provider might have its own upgrade instructions to follow now. | ||
| Check the [addons](/docs/concepts/cluster-administration/addons/) page to | ||
| find your CNI provider and see if there are additional upgrade steps | ||
| necessary. | ||
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| ## Upgrading your worker nodes | ||
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| For each worker node (referred to as `$WORKER` below) in your cluster, upgrade `kubelet` by executing the following commands: | ||
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| 1. Prepare the node for maintenance, marking it unschedulable and evicting the workload: | ||
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| ```shell | ||
| $ kubectl cordon $WORKER | ||
| $ kubectl drain $WORKER | ||
| ``` | ||
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| 2. Upgrade the `kubelet` version on the `$WORKER` node by using a Linux distribution-specific package manager: | ||
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| If the node is running a Debian-based distro such as Ubuntu, run: | ||
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| ```shell | ||
| $ apt-get update | ||
| $ apt-get install -y kubelet | ||
| ``` | ||
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| If the node is running CentOS or the like, run: | ||
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| ```shell | ||
| $ yum update | ||
| $ yum install -y kubelet | ||
| ``` | ||
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| Now the new version of the `kubelet` should be running on the `$WORKER` node. Verify this using the following command: | ||
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| ```shell | ||
| $ systemctl status kubelet | ||
| ``` | ||
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| 3. Bring the `$WORKER` node back online by marking it schedulable: | ||
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| ```shell | ||
| $ kubectl uncordon $WORKER | ||
| ``` | ||
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| 4. After upgrading `kubelet` on each worker node in your cluster, verify that all nodes are available again by executing the following (from anywhere, for example, from outside the cluster): | ||
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| ```shell | ||
| $ kubectl get nodes | ||
| ``` | ||
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| If the `STATUS` column of the above command shows `Ready` for all of your worker nodes, you are done. | ||
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| ## Recovering from a bad state | ||
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| If `kubeadm upgrade` somehow fails and fails to roll back, due to an unexpected shutdown during execution for instance, | ||
| you may run `kubeadm upgrade` again as it is idempotent and should eventually make sure the actual state is the desired state you are declaring. | ||
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| You can use `kubeadm upgrade` to change a running cluster with `x.x.x --> x.x.x` with `--force`, which can be used to recover from a bad state. | ||
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| {% endcapture %} | ||
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| {% include templates/task.md %} |