4. k8s版本升级

# 准备工作
1. 在master节点上查看此时的kubernetes的版本
```bash
[root@master1 ~]# kubeadm version
kubeadm version: &version.Info{Major:"1", Minor:"27", GitVersion:"v1.27.6", GitCommit:"741c8db18a52787d734cbe4795f0b4ad860906d6", GitTreeState:"clean", BuildDate:"2023-09-13T09:19:54Z", GoVersion:"go1.20.8", Compiler:"gc", Platform:"linux/amd64"}
```

2. 查询最新版本号
```bash
[root@master1 ~]# dnf list kubeadm --showduplicates | sort -r
```

# 升级操作

## 升级最新版本

1. master和node节点执行升级命令
```bash
yum update -y kubeadm kubectl kubelet
```

2. master节点验证升级版本
```bash
kubeadm upgrade plan
```

## 升级指定版本

1. master和node节点执行升级命令 yum update -y kubelet-1.21.9 kubeadm-1.21.9 kubectl-1.21.9
2. 升级到指定版本(master节点执行) kubeadm upgrade apply v1.21.9

![image.png](/media/202406/17.4.15290403_image1.png)

3. master和node重启kubelet systemctl daemon-reload systemctl restart kubelet

# 验证

1. 查看node信息

![未命名图片.png](/media/202406/17.4.15290403_image2.png)

# 常见问题
现象：从1.19.X升级到1.20.X时，kube-proxy无法启动，日志报错如下
```bash
F1029 01:23:10.186401 1 server.go:488] failed complete: unrecognized feature gate: SupportIPVSProxyMode
```
原因： kube-proxy无法识别SupportIPVSProxyMode这个字段,于是访问官方查看最新版本ipvs开启的正确配置,通过[https://github.com/kubernetes/kubernetes/blob/master/pkg/proxy/ipvs/README.md](https://github.com/kubernetes/kubernetes/blob/master/pkg/proxy/ipvs/README.md)可以看到官方说明:
```bash
kubeProxy:
 config:
 mode: ipvs
```
处理办法：
```bash
# 查看kube-proxy配置文件名称
[root@k8s-master ~]# kubectl get cm -n kube-system 
NAME DATA AGE
coredns 1 36d
extension-apiserver-authentication 6 36d
kube-proxy 2 36d
kube-root-ca.crt 1 11h
kubeadm-config 2 36d
kubelet-config-1.19 1 36d
kubelet-config-1.20 1 11h
# 编辑configmap
[root@k8s-master ~]# kubectl edit cm -n kube-system kube-proxy 
enableProfiling: false # 注释下面两行内容
#featureGates: 
# SupportIPVSProxyMode: true
healthzBindAddress: ""
```