Kubernetes集群升级指南-编程阁

前言

本文演示kubernetes集群从v1.24.1升级到v1.29.15。

一、集群升级过程辅助命令

（1）查看节点上运行的pod。

kubectl get pod -o wide |grep <nodename>

（2）查看集群配置文件。

kubectl -n kube-system get cm kubeadm-config -o yaml

（3）查看当前集群节点。

kubectl get node

二、升级master节点

2.1、升级kubeadm。

# 更新包管理器
yum update
# 查看可用版本
apt-cache madison kubeadm
yum list | grep kubeadm
# 更新
yum update -y kubeadm

# 验证版本
kubeadm version

2.2、验证升级计划

（1）检查可升级到哪些版本，并验证你当前的集群是否可升级。

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: v1.28.15
[upgrade/versions] kubeadm version: v1.29.15
I0327 11:28:43.151508 1125701 version.go:256] remote version is much newer: v1.32.3; falling back to: stable-1.29
[upgrade/versions] Target version: v1.29.15
[upgrade/versions] Latest version in the v1.28 series: v1.28.15

Components that must be upgraded manually after you have upgraded the control plane with 'kubeadm upgrade apply':
COMPONENT CURRENT TARGET
kubelet 3 x v1.28.15 v1.29.15

Upgrade to the latest stable version:

COMPONENT CURRENT TARGET
kube-apiserver v1.28.15 v1.29.15
kube-controller-manager v1.28.15 v1.29.15
kube-scheduler v1.28.15 v1.29.15
kube-proxy v1.28.15 v1.29.15
CoreDNS v1.10.1 v1.11.1
etcd 3.5.15-0 3.5.16-0

You can now apply the upgrade by executing the following command:

kubeadm upgrade apply v1.29.15

_____________________________________________________________________

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
_____________________________________________________________________

注意下面的MANUAL字段：

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
_____________________________________________________________________

指示哪些主键需要手动升级，如果是yes就要手动升级。

（2）显示哪些差异将被应用于现有的静态 pod 资源清单。

kubeadm upgrade diff 1.29.15
[upgrade/diff] Reading configuration from the cluster...
[upgrade/diff] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -o yaml'
--- /etc/kubernetes/manifests/kube-apiserver.yaml
+++ new manifest
@@ -40,7 +40,7 @@
- --service-cluster-ip-range=10.96.0.0/12
- --tls-cert-file=/etc/kubernetes/pki/apiserver.crt
- --tls-private-key-file=/etc/kubernetes/pki/apiserver.key
- image: registry.aliyuncs.com/google_containers/kube-apiserver:v1.28.15
+ image: registry.aliyuncs.com/google_containers/kube-apiserver:1.29.15
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 8
--- /etc/kubernetes/manifests/kube-controller-manager.yaml
+++ new manifest
@@ -28,7 +28,7 @@
- --service-account-private-key-file=/etc/kubernetes/pki/sa.key
- --service-cluster-ip-range=10.96.0.0/12
- --use-service-account-credentials=true
- image: registry.aliyuncs.com/google_containers/kube-controller-manager:v1.28.15
+ image: registry.aliyuncs.com/google_containers/kube-controller-manager:1.29.15
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 8
--- /etc/kubernetes/manifests/kube-scheduler.yaml
+++ new manifest
@@ -16,7 +16,7 @@
- --bind-address=127.0.0.1
- --kubeconfig=/etc/kubernetes/scheduler.conf
- --leader-elect=true
- image: registry.aliyuncs.com/google_containers/kube-scheduler:v1.28.15
+ image: registry.aliyuncs.com/google_containers/kube-scheduler:1.29.15
imagePullPolicy: IfNotPresent
livenessProbe:
failureThreshold: 8

2.3、master节点升级

（1）升级到 1.29.15版本，此命令仅升级master节点（control plane）。

kubeadm upgrade apply v1.29.15
[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 "v1.29.15"
[upgrade/versions] Cluster version: v1.28.15
[upgrade/versions] kubeadm version: v1.29.15
[upgrade] Are you sure you want to proceed? [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 "v1.29.15" (timeout: 5m0s)...
[upgrade/etcd] Upgrading to TLS for etcd
[upgrade/staticpods] Preparing for "etcd" upgrade
[upgrade/staticpods] Renewing etcd-server certificate
[upgrade/staticpods] Renewing etcd-peer certificate
[upgrade/staticpods] Renewing etcd-healthcheck-client certificate
[upgrade/staticpods] Moved new manifest to "/etc/kubernetes/manifests/etcd.yaml" and backed up old manifest to "/etc/kubernetes/tmp/kubeadm-backup-manifests-2025-03-27-11-32-38/etcd.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=etcd
[upgrade/staticpods] Component "etcd" upgraded successfully!
[upgrade/etcd] Waiting for etcd to become available
[upgrade/staticpods] Writing new Static Pod manifests to "/etc/kubernetes/tmp/kubeadm-upgraded-manifests2230279311"
[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-2025-03-27-11-32-38/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-2025-03-27-11-32-38/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-2025-03-27-11-32-38/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!
[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
[upgrade] Backing up kubelet config file to /etc/kubernetes/tmp/kubeadm-kubelet-config3777955110/config.yaml
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubeconfig] Writing "admin.conf" kubeconfig file
[kubeconfig] Writing "super-admin.conf" kubeconfig file
[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 "v1.29.15". Enjoy!

[upgrade/kubelet] Now that your control plane is upgraded, please proceed with upgrading your kubelets if you haven't already done so.

（2）腾空节点，即将节点上除守护进程之外的其他进程调度到其他节点，同时将开启调度保护。

kubectl drain <nodename> --ignore-daemonsets
$ kubectl drain k8s-master1 --ignore-daemonsets
node/k8s-master1 cordoned
WARNING: ignoring DaemonSet-managed Pods: kube-flannel/kube-flannel-ds-nxz4d, kube-system/kube-proxy-pbnk4
evicting pod kube-system/coredns-c676cc86f-twm96
evicting pod kube-system/coredns-c676cc86f-mdgbn
pod/coredns-c676cc86f-mdgbn evicted
pod/coredns-c676cc86f-twm96 evicted
node/k8s-master1 drained

$ kubectl get pod -A
NAMESPACE NAME READY STATUS RESTARTS AGE
kube-flannel kube-flannel-ds-nxz4d 1/1 Running 0 136m
kube-system coredns-c676cc86f-7stvs 0/1 Pending 0 60s
kube-system coredns-c676cc86f-vmkgv 0/1 Pending 0 60s
kube-system etcd-k8s-master1 1/1 Running 0 11m
kube-system kube-apiserver-k8s-master1 1/1 Running 0 10m
kube-system kube-controller-manager-k8s-master1 1/1 Running 0 10m
kube-system kube-proxy-pbnk4 1/1 Running 0 9m44s
kube-system kube-scheduler-k8s-master1 1/1 Running 0 9m58s

$ kubectl get node
NAME STATUS ROLES AGE VERSION
k8s-master1 Ready,SchedulingDisabled control-plane 162m v1.24.1

（3）升级kubelet与kubectl组件。

yum update -y kubelet

（4）重启 kubelet。

systemctl daemon-reload
systemctl restart kubelet

（5）解除调度保护。

kubectl uncordon <nodename>

三、升级node节点

（1）升级节点kubelet 配置。

kubeadm upgrade node

（2）腾空节点，同时开启调度保护，此命令请在master节点操作

kubectl drain <nodename> --ignore-daemonsets

（3）升级kubelet与kubectl组件。

yum update -y kubelet

（4）重启 kubelet。

systemctl daemon-reload
systemctl restart kubelet

（5）解除调度保护，master节点上执行该命令。

kubectl uncordon <nodename>

总结

每个版本的升级都不一样，所以要根据版本进行适当调整，不作为万能指导。升级过程：

升级master组件。
升级worker节点组件，调度保护、排空节点、worker节点组件升级、解除保护。

Kubernetes集群的升级可以分为以下几个步骤：

备份数据。在升级之前，需要备份Kubernetes集群的数据，包括访问控制、配置文件、数据卷等。
选择升级方式。Kubernetes集群的升级方式可以分为两种：滚动升级和强制替换。滚动升级是指逐个升级每个节点，直到所有节点都升级完成。强制替换是指一次性替换所有节点，将旧节点直接替换为新节点。
准备新版本。Kubernetes升级需要准备新版本的二进制文件和镜像文件。可以从Kubernetes官方网站下载最新版本的二进制文件和镜像文件，并上传到集群中的节点上。
升级Master节点。首先需要升级Master节点，使用新版本的二进制文件替换旧版本的二进制文件，并启动新版本的Kubernetes API Server、ControllerKubernetes是一个快速发展的开源项目，为了保持其功能和安全性，集群的升级是必须的。
- 查看升级文档：首先需要查看官方的升级文档，了解升级过程中需要注意的事项。
- 备份数据：在升级前需要备份当前的数据，以防升级过程中的意外情况导致数据丢失。
- 准备好备份：在升级前需要确保备份的可用性，以便在需要时能够 Manager和Scheduler。
升级Node节点。接下来需要升级Node节点。首先需要将节点上的Kubelet和kube-proxy服务停止，使用新版本的二进制文件替换旧版本的二进制文件，然后启动新版本的Kubelet和kube-proxy服务。
验证升级结果。升级完成后，需要验证恢复数据。
- 升级前的测试：可以在测试环境中进行升级测试，以确保升级过程和升级后的集群正常运行。
- 升级Node：首先需要升级每个Node节点中的Kubernetes组件，包括kubelet和kube-proxy等。
- 升级Control Plane：然后需要升级Control Plane中的Kubernetes组件，包括kube-apiserver、kube-controller-manager和kube-scheduler等。
- 升级Kubernetes对象：升级完Control Plane后，需要升级Kubernetes对象，如Deployment集群是否正常运行。可以使用kubectl命令查看集群的状态和资源对象的状态，确保所有的服务都能够正常访问。
回滚升级。如果升级失败或出现问题，可以回滚到之前的版本。回滚的过程与升级的过程相同，只需要使用旧版本的二进制文件和镜像文件即可。