1. 升级概要
- k8s版本：以 x.y.z 表示，其中 x 是主要版本， y 是次要版本，z 是补丁版本,不能跳过次要版本升级，比如1.28.0->1.30.0，补丁版本可以跳跃更新，比如1.28.0->1.28.10
- 推荐使用与版本匹配的 kubelet 和 kubeadm，最好各组件版本保持一致
- 升级后，因为容器spec的哈希值已更改，所有容器都会被重新启动
- 升级过程需要腾空升每个节点，将工作负载迁移
2. 升级过程
2.1 升级主控制平面节点
控制面节点上的升级过程应该每次处理一个节点。 首先选择一个要先行升级的控制面节点。该节点上必须拥有 /etc/kubernetes/admin.conf 文件。本次模拟从1.23.17升级到1.24.15版本,其他版本升级类似。
2.1.1 升级kubeadm
# 查看当前版本信息
$ kubectl get nodes
NAME STATUS ROLES AGE VERSION
k8s-master01 Ready control-plane,master 148d v1.23.17
k8s-node01 Ready <none> 148d v1.23.17
k8s-node02 Ready <none> 148d v1.23.17
k8s-node03 Ready <none> 148d v1.23.17
# 查看可升级版本
$ yum list --show-duplicates kubeadm |grep '1.24.'
kubeadm.x86_64 1.24.0-0 kubernetes
kubeadm.x86_64 1.24.1-0 kubernetes
kubeadm.x86_64 1.24.2-0 kubernetes
kubeadm.x86_64 1.24.3-0 kubernetes
kubeadm.x86_64 1.24.4-0 kubernetes
kubeadm.x86_64 1.24.5-0 kubernetes
kubeadm.x86_64 1.24.6-0 kubernetes
kubeadm.x86_64 1.24.7-0 kubernetes
kubeadm.x86_64 1.24.8-0 kubernetes
kubeadm.x86_64 1.24.9-0 kubernetes
kubeadm.x86_64 1.24.10-0 kubernetes
kubeadm.x86_64 1.24.11-0 kubernetes
kubeadm.x86_64 1.24.12-0 kubernetes
kubeadm.x86_64 1.24.13-0 kubernetes
kubeadm.x86_64 1.24.14-0 kubernetes
kubeadm.x86_64 1.24.15-0 kubernetes
kubeadm.x86_64 1.24.16-0 kubernetes
kubeadm.x86_64 1.24.17-0 kubernetes
$ yum -y install kubeadm-1.24.15
$ kubeadm version -o yaml
clientVersion:
buildDate: "2023-06-14T09:54:33Z"
compiler: gc
gitCommit: 2c67202dc0bb96a7a837cbfb8d72e1f34dfc2808
gitTreeState: clean
gitVersion: v1.24.15
goVersion: go1.19.10
major: "1"
minor: "24"
platform: linux/amd64
2.1.2 校验升级计划，不能有报错信息
$ kubeadm upgrade plan
[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 -o yaml'
[preflight] Running pre-flight checks.
[upgrade] Running cluster health checks
[upgrade] Fetching available versions to upgrade to
[upgrade/versions] Cluster version: v1.23.17
[upgrade/versions] kubeadm version: v1.24.15
W0606 18:11:22.084648 122592 version.go:104] could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable.txt": Get "https://cdn.dl.k8s.io/release/stable.txt": dial tcp 146.75.113.55:443: i/o timeout (Client.Timeout exceeded while awaiting headers)
W0606 18:11:22.084821 122592 version.go:105] falling back to the local client version: v1.24.15
[upgrade/versions] Target version: v1.24.15
[upgrade/versions] Latest version in the v1.23 series: v1.23.17
Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
COMPONENT CURRENT TARGET
kubelet 4 x v1.23.17 v1.24.15
Upgrade to the latest stable version:
COMPONENT CURRENT TARGET
kube-apiserver v1.23.17 v1.24.15
kube-controller-manager v1.23.17 v1.24.15
kube-scheduler v1.23.17 v1.24.15
kube-proxy v1.23.17 v1.24.15
CoreDNS v1.8.6 v1.8.6
etcd 3.5.6-0 3.5.6-0
You can now apply the upgrade by executing the following command:
kubeadm upgrade apply v1.24.15
_____________________________________________________________________
The table below shows the current state of component configs as understood by this version of kubeadm.
Configs that have a "yes" mark in the "MANUAL UPGRADE REQUIRED" column require manual config upgrade or
resetting to kubeadm defaults before a successful upgrade can be performed. The version to manually
upgrade to is denoted in the "PREFERRED VERSION" column.
API GROUP CURRENT VERSION PREFERRED VERSION MANUAL UPGRADE REQUIRED
kubeproxy.config.k8s.io v1alpha1 v1alpha1 no
kubelet.config.k8s.io v1beta1 v1beta1 no
_____________________________________________________________________
2.1.3. 执行升级命令，升级控制面组件
$ kubeadm upgrade apply v1.24.15
[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 -o yaml'
[preflight] Running pre-flight checks.
[upgrade] Running cluster health checks
[upgrade/version] You have chosen to change the cluster version to "v1.24.15"
[upgrade/versions] Cluster version: v1.23.17
[upgrade/versions] kubeadm version: v1.24.15
[upgrade/confirm] Are you sure you want to proceed with the upgrade? [y/N]: y
[upgrade/prepull] Pulling images required for setting up a Kubernetes cluster
[upgrade/prepull] This might take a minute or two, depending on the speed of your internet connection
[upgrade/prepull] You can also perform this action in beforehand using 'kubeadm config images pull'
[upgrade/apply] Upgrading your Static Pod-hosted control plane to version "v1.24.15" (timeout: 5m0s)...
[upgrade/etcd] Upgrading to TLS for etcd
[upgrade/staticpods] Preparing for "etcd" upgrade
[upgrade/staticpods] Current and new manifests of etcd are equal, skipping upgrade
[upgrade/etcd] Waiting for etcd to become available
[upgrade/staticpods] Writing new Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests2379417340"
[upgrade/staticpods] Preparing for "kube-apiserver" upgrade
[upgrade/staticpods] Renewing apiserver certificate
[upgrade/staticpods] Renewing apiserver-kubelet-client certificate
[upgrade/staticpods] Renewing front-proxy-client certificate
[upgrade/staticpods] Renewing apiserver-etcd-client certificate
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-apiserver.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2024-06-06-18-17-42/kube-apiserver.yaml"
[upgrade/staticpods] Waiting for the kubelet to restart the component
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s)
[apiclient] Found 1 Pods for label selector component=kube-apiserver
[upgrade/staticpods] Component "kube-apiserver" upgraded successfully!
[upgrade/staticpods] Preparing for "kube-controller-manager" upgrade
[upgrade/staticpods] Renewing controller-manager.conf certificate
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-controller-manager.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2024-06-06-18-17-42/kube-controller-manager.yaml"
[upgrade/staticpods] Waiting for the kubelet to restart the component
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s)
[apiclient] Found 1 Pods for label selector component=kube-controller-manager
[upgrade/staticpods] Component "kube-controller-manager" upgraded successfully!
[upgrade/staticpods] Preparing for "kube-scheduler" upgrade
[upgrade/staticpods] Renewing scheduler.conf certificate
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/kube-scheduler.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2024-06-06-18-17-42/kube-scheduler.yaml"
[upgrade/staticpods] Waiting for the kubelet to restart the component
[upgrade/staticpods] This might take a minute or longer depending on the component/version gap (timeout 5m0s)
[apiclient] Found 1 Pods for label selector component=kube-scheduler
[upgrade/staticpods] Component "kube-scheduler" upgraded successfully!
[upgrade/postupgrade] Removing the deprecated label node-role.kubernetes.io/master='' from all control plane Nodes. After this step only the label node-role.kubernetes.io/control-plane='' will be present on control plane Nodes.
[upgrade/postupgrade] Adding the new taint &Taint{Key:node-role.kubernetes.io/control-plane,Value:,Effect:NoSchedule,TimeAdded:<nil>,} to all control plane Nodes. After this step both taints &Taint{Key:node-role.kubernetes.io/control-plane,Value:,Effect:NoSchedule,TimeAdded:<nil>,} and &Taint{Key:node-role.kubernetes.io/master,Value:,Effect:NoSchedule,TimeAdded:<nil>,} should be present on control plane Nodes.
[upload-config] Storing the configuration used in ConfigMap "kubeadm-config" in the "kube-system" Namespace
[kubelet] Creating a ConfigMap "kubelet-config" in namespace kube-system with the configuration for the kubelets in the cluster
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to get nodes
[bootstrap-token] Configured RBAC rules to allow Node Bootstrap tokens to post CSRs in order for nodes to get long term certificate credentials
[bootstrap-token] Configured RBAC rules to allow the csrapprover controller automatically approve CSRs from a Node Bootstrap Token
[bootstrap-token] Configured RBAC rules to allow certificate rotation for all node client certificates in the cluster
[addons] Applied essential addon: CoreDNS
[addons] Applied essential addon: kube-proxy
[upgrade/successful] SUCCESS! Your cluster was upgraded to "v1.24.15". Enjoy!
[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets if you haven't already done so.
2.1.4. 腾空该节点，将节点标记为不可调度并驱逐所有负载，准备节点的维护
$ kubectl drain k8s-master01 --ignore-daemonsets
node/k8s-master01 cordoned
WARNING: ignoring DaemonSet-managed Pods: default/ds-ng-d6g58, kube-flannel/kube-flannel-ds-qmpmf, kube-system/kube-proxy-tc92t
evicting pod kube-system/coredns-65c54cc984-sjd7x
pod/coredns-65c54cc984-sjd7x evicted
node/k8s-master01 drained
2.1.5. 升级 kubelet 和 kubectl
$ yum -y install kubelet-1.24.15 kubectl-1.24.15
$ systemctl daemon-reload
$ systemctl restart kubelet
2.1.6. 解除节点封锁，通过将节点标记为可调度，让其重新上线
$ kubectl uncordon k8s-master01
node/k8s-master01 uncordoned
2.2 升级其他控制平面节点
对于其他控制面节点，有两步不一样：
- 不需要执行kubeadm upgrade plan
- kubeadm upgrade node 替换 kubeadm upgrade apply
其他流程一样。