1.1 升级步骤

注意kubectl命令主节点执行,yum命令需要升级的服务器执行;

查看当前系统支持的所有k8s版本和当前版本

yum list --showduplicates kubeadm --disableexcludes=kubernetes

2.1.1 升级控制节点

1、查看当前版本和升级计划（即可以从目前版本升级到哪个版本）

kubectl version

#匹配最佳升级版本

kubeadm upgrade plan

#首先我们保留 kubeadm config 文件：

kubeadm config view > kubeadm-config.yaml

vim kubeadm-config.yaml

apiServer:
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: 12.10.100.226:8443
controllerManager: {}
dns:
  type: CoreDNS
etcd:
  external:
    caFile: /etc/etcd/pki/ca.pem
    certFile: /etc/etcd/pki/client.pem
    endpoints:
    - https://12.10.100.220:2379
    - https://12.10.100.221:2379
    - https://12.10.100.222:2379
    keyFile: /etc/etcd/pki/client-key.pem
imageRepository: registry.aliyuncs.com/k8sxio  # 修改成阿里云镜像源
kind: ClusterConfiguration
kubernetesVersion: v1.18.20  #修改成想要升级版本
networking:
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.96.0.0/12
scheduler: {}

#下载包

yum makecache fast && yum install -y kubeadm-1.18.20-0 kubectl-1.18.20-0

#下载镜像
kubeadm config images pull --config kubeadm-config.yaml
#测试
kubeadm upgrade apply v1.18.20 --config kubeadm-config.yaml --dry-run


#然后就可以执行真正的升级命令
kubeadm upgrade apply v1.18.20 --config kubeadm-config.yaml

3、升级kubelet和kubectl

yum install -y kubelet-1.18.20-0 kubectl-1.18.20-0 --disableexcludes=kubernetes
systemctl daemon-reload
systemctl restart kubelet

#查看当前版本

kubectl version

kubectl get nodes

4.1 升级工作节点

#子节点执行

yum install -y kubeadm-1.18.20-0 --disableexcludes=kubernetes

#主节点执行-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-node01 --ignore-daemonsets

#更新子节点

kubeadm upgrade node

#主节点执行-通过将节点标记为可调度，让节点重新上线:

kubectl uncordon k8s-node01 

#子节点执行

yum install -y kubelet-1.18.20-0 kubectl-1.18.20-0 --disableexcludes=kubernetes

systemctl daemon-reload
systemctl restart kubelet

#主节点执行

kubectl version
kubectl get nodes

成功截图