其中一台master执行
yum install -y kubeadm-1.28.2*
任一master执行验证集群能否升级
kubeadm upgrade plan
master1上执行
执行升级命令（这一步需要等待）
kubeadm upgrade apply v1.28.2
其它master上执行
yum install -y kubeadm-1.28.2* kubeadm upgrade node
master升级
yum install -y kubelet-1.28.2* kubectl-1.28.2* --disableexcludes=kubernetes systemctl daemon-reload systemctl restart kubelet
等一台结束后通过kubectl get node查看对应的master是否已经变成v1.27.6，再去执行另外一台master，依次升级完所有master节点
node上升级
yum install -y kubeadm-1.28.2* kubelet-1.28.2* kubectl-1.28.2* kubeadm upgrade node systemctl daemon-reload systemctl restart kubelet