如何修改Kubernetes的SSL證書有效期

主機配置規劃

為什么要修改證書有效期

Kubernetes默認的證書有效期都是1年，因此需要我們每年都更新證書，顯然這對我們實際生產環境來說是很不友好的；因此我們要對Kubernetes的SSL證書有效期進行修改，

證書有效期查看

 1 [root@k8s-master pki]# pwd
 2 /etc/kubernetes/pki
 3 [root@k8s-master pki]# ll
 4 total 56
 5 -rw-r--r-- 1 root root 1224 May 12 15:51 apiserver.crt
 6 -rw-r--r-- 1 root root 1090 May 12 15:51 apiserver-etcd-client.crt
 7 -rw------- 1 root root 1675 May 12 15:51 apiserver-etcd-client.key
 8 -rw------- 1 root root 1675 May 12 15:51 apiserver.key
 9 -rw-r--r-- 1 root root 1099 May 12 15:51 apiserver-kubelet-client.crt
10 -rw------- 1 root root 1675 May 12 15:51 apiserver-kubelet-client.key
11 -rw-r--r-- 1 root root 1025 May 12 15:51 ca.crt
12 -rw------- 1 root root 1675 May 12 15:51 ca.key
13 drwxr-xr-x 2 root root  162 May 12 15:51 etcd
14 -rw-r--r-- 1 root root 1038 May 12 15:51 front-proxy-ca.crt
15 -rw------- 1 root root 1675 May 12 15:51 front-proxy-ca.key
16 -rw-r--r-- 1 root root 1058 May 12 15:51 front-proxy-client.crt
17 -rw------- 1 root root 1675 May 12 15:51 front-proxy-client.key
18 -rw------- 1 root root 1679 May 12 15:51 sa.key
19 -rw------- 1 root root  451 May 12 15:51 sa.pub
20 [root@k8s-master pki]# 
21 [root@k8s-master pki]# for i in $(ls *.crt); do echo "===== $i ====="; openssl x509 -in $i -text -noout | grep -A 3 'Validity' ; done
22 ===== apiserver.crt =====
23         Validity
24             Not Before: May 12 07:51:36 2020 GMT
25             Not After : May 12 07:51:36 2021 GMT
26         Subject: CN=kube-apiserver
27 ===== apiserver-etcd-client.crt =====
28         Validity
29             Not Before: May 12 07:51:37 2020 GMT
30             Not After : May 12 07:51:38 2021 GMT
31         Subject: O=system:masters, CN=kube-apiserver-etcd-client
32 ===== apiserver-kubelet-client.crt =====
33         Validity
34             Not Before: May 12 07:51:36 2020 GMT
35             Not After : May 12 07:51:37 2021 GMT
36         Subject: O=system:masters, CN=kube-apiserver-kubelet-client
37 ===== ca.crt =====
38         Validity
39             Not Before: May 12 07:51:36 2020 GMT
40             Not After : May 10 07:51:36 2030 GMT
41         Subject: CN=kubernetes
42 ===== front-proxy-ca.crt =====
43         Validity
44             Not Before: May 12 07:51:37 2020 GMT
45             Not After : May 10 07:51:37 2030 GMT
46         Subject: CN=front-proxy-ca
47 ===== front-proxy-client.crt =====
48         Validity
49             Not Before: May 12 07:51:37 2020 GMT
50             Not After : May 12 07:51:37 2021 GMT
51         Subject: CN=front-proxy-client
52 [root@k8s-master pki]#

由上可見，除了ca根證書，其他證書有效期都是1年，

證書有效時限修改

go環境部署

go語言中文網

https://studygolang.com/

在Linux命令列下載

1 [root@k8s-master software]# wget https://studygolang.com/dl/golang/go1.14.6.linux-amd64.tar.gz
2 [root@k8s-master software]# tar xf go1.14.6.linux-amd64.tar.gz -C /usr/local/
3 [root@k8s-master software]# vim /etc/profile   # 最后面添加如下資訊
4 # go語言環境變數
5 export PATH=$PATH:/usr/local/go/bin
6 [root@k8s-master software]# source /etc/profile

Kubernetes原始碼下載與更改證書策略

當期k8s版本

1 [root@k8s-master software]# kubectl version
2 Client Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.4", GitCommit:"8d8aa39598534325ad77120c120a22b3a990b5ea", GitTreeState:"clean", BuildDate:"2020-03-12T21:03:42Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"linux/amd64"}
3 Server Version: version.Info{Major:"1", Minor:"17", GitVersion:"v1.17.4", GitCommit:"8d8aa39598534325ad77120c120a22b3a990b5ea", GitTreeState:"clean", BuildDate:"2020-03-12T20:55:23Z", GoVersion:"go1.13.8", Compiler:"gc", Platform:"linux/amd64"}

根據k8s版本下載原始碼

操作步驟

 1 [root@k8s-master software]# wget https://github.com/kubernetes/kubernetes/archive/v1.17.4.tar.gz
 2 [root@k8s-master software]# tar xf v1.17.4.tar.gz && cd kubernetes-1.17.4
 3 [root@k8s-master kubernetes-1.17.4]# vim cmd/kubeadm/app/util/pkiutil/pki_helpers.go
 4 ………………
 5 func NewSignedCert(cfg *certutil.Config, key crypto.Signer, caCert *x509.Certificate, caKey crypto.Signer) (*x509.Certificate, error) {
 6         // 添加如下行 有效時間 100 年
 7         const effectyear = time.Hour * 24 * 365 * 100
 8 
 9         serial, err := cryptorand.Int(cryptorand.Reader, new(big.Int).SetInt64(math.MaxInt64))
10         if err != nil {
11                 return nil, err
12         }
13         if len(cfg.CommonName) == 0 {
14                 return nil, errors.New("must specify a CommonName")
15         }
16         if len(cfg.Usages) == 0 {
17                 return nil, errors.New("must specify at least one ExtKeyUsage")
18         }
19 
20         certTmpl := x509.Certificate{
21                 Subject: pkix.Name{
22                         CommonName:   cfg.CommonName,
23                         Organization: cfg.Organization,
24                 },
25                 DNSNames:     cfg.AltNames.DNSNames,
26                 IPAddresses:  cfg.AltNames.IPs,
27                 SerialNumber: serial,
28                 NotBefore:    caCert.NotBefore,
29                 // NotAfter:     time.Now().Add(kubeadmconstants.CertificateValidity).UTC(),
30                 NotAfter:     time.Now().Add(effectyear).UTC(),   // 修改行
31                 KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
32                 ExtKeyUsage:  cfg.Usages,
33         }
34 [root@k8s-master kubernetes-1.17.4]# 
35 # 注意路徑
36 [root@k8s-master kubernetes-1.17.4]# make WHAT=cmd/kubeadm GOFLAGS=-v
37 # 將更新后的kubeadm拷貝到指定位置
38 [root@k8s-master kubernetes-1.17.4]# cp -a _output/bin/kubeadm /root/kubeadm-new

更新kubeadm并備份原證書

1 # kubeadm更新
2 mv /usr/bin/kubeadm /usr/bin/kubeadm_20200725
3 mv /root/kubeadm-new /usr/bin/kubeadm
4 chmod 755 /usr/bin/kubeadm
5 # 原證書備份
6 cp -a /etc/kubernetes/pki/ /etc/kubernetes/pki_20200725

證書更新

操作如下：

 1 # 證書更新
 2 [root@k8s-master ~]# kubeadm alpha certs renew all --config=/root/k8s_install/kubeadm-config.yaml
 3 # 查看新證書有效期
 4 [root@k8s-master ~]# cd /etc/kubernetes/pki
 5 [root@k8s-master pki]# ll
 6 total 56
 7 -rw-r--r-- 1 root root 1224 Jul 25 18:44 apiserver.crt
 8 -rw-r--r-- 1 root root 1094 Jul 25 18:44 apiserver-etcd-client.crt
 9 -rw------- 1 root root 1675 Jul 25 18:44 apiserver-etcd-client.key
10 -rw------- 1 root root 1679 Jul 25 18:44 apiserver.key
11 -rw-r--r-- 1 root root 1103 Jul 25 18:44 apiserver-kubelet-client.crt
12 -rw------- 1 root root 1679 Jul 25 18:44 apiserver-kubelet-client.key
13 -rw-r--r-- 1 root root 1025 May 12 15:51 ca.crt
14 -rw------- 1 root root 1675 May 12 15:51 ca.key
15 drwxr-xr-x 2 root root  162 May 12 15:51 etcd
16 -rw-r--r-- 1 root root 1038 May 12 15:51 front-proxy-ca.crt
17 -rw------- 1 root root 1675 May 12 15:51 front-proxy-ca.key
18 -rw-r--r-- 1 root root 1058 Jul 25 18:44 front-proxy-client.crt
19 -rw------- 1 root root 1679 Jul 25 18:44 front-proxy-client.key
20 -rw------- 1 root root 1679 May 12 15:51 sa.key
21 -rw------- 1 root root  451 May 12 15:51 sa.pub
22 [root@k8s-master pki]# 
23 [root@k8s-master pki]# for i in $(ls *.crt); do echo "===== $i ====="; openssl x509 -in $i -text -noout | grep -A 3 'Validity' ; done
24 ===== apiserver.crt =====
25         Validity
26             Not Before: May 12 07:51:36 2020 GMT
27             Not After : Jul  1 10:44:20 2120 GMT
28         Subject: CN=kube-apiserver
29 ===== apiserver-etcd-client.crt =====
30         Validity
31             Not Before: May 12 07:51:37 2020 GMT
32             Not After : Jul  1 10:44:20 2120 GMT
33         Subject: O=system:masters, CN=kube-apiserver-etcd-client
34 ===== apiserver-kubelet-client.crt =====
35         Validity
36             Not Before: May 12 07:51:36 2020 GMT
37             Not After : Jul  1 10:44:20 2120 GMT
38         Subject: O=system:masters, CN=kube-apiserver-kubelet-client
39 ===== ca.crt =====
40         Validity
41             Not Before: May 12 07:51:36 2020 GMT
42             Not After : May 10 07:51:36 2030 GMT
43         Subject: CN=kubernetes
44 ===== front-proxy-ca.crt =====
45         Validity
46             Not Before: May 12 07:51:37 2020 GMT
47             Not After : May 10 07:51:37 2030 GMT
48         Subject: CN=front-proxy-ca
49 ===== front-proxy-client.crt =====
50         Validity
51             Not Before: May 12 07:51:37 2020 GMT
52             Not After : Jul  1 10:44:22 2120 GMT
53         Subject: CN=front-proxy-client

由上可見，除了CA根證書，其他證書有效期已經改為 100 年，

kubeadm-config.yaml檔案參見如下

 1 [root@k8s-master k8s_install]# pwd
 2 /root/k8s_install
 3 [root@k8s-master k8s_install]# kubeadm config print init-defaults > kubeadm-config.yaml
 4 # 做了適當修改
 5 [root@k8s-master k8s_install]# cat kubeadm-config.yaml   
 6 apiVersion: kubeadm.k8s.io/v1beta2
 7 bootstrapTokens:
 8 - groups:
 9   - system:bootstrappers:kubeadm:default-node-token
10   token: abcdef.0123456789abcdef
11   ttl: 24h0m0s
12   usages:
13   - signing
14   - authentication
15 kind: InitConfiguration
16 localAPIEndpoint:
17   # 改為本機內網IP
18   advertiseAddress: 172.16.1.110
19   bindPort: 6443
20 nodeRegistration:
21   criSocket: /var/run/dockershim.sock
22   name: k8s-master
23   taints:
24   - effect: NoSchedule
25     key: node-role.kubernetes.io/master
26 ---
27 apiServer:
28   timeoutForControlPlane: 4m0s
29 apiVersion: kubeadm.k8s.io/v1beta2
30 certificatesDir: /etc/kubernetes/pki
31 clusterName: kubernetes
32 controllerManager: {}
33 dns:
34   type: CoreDNS
35 etcd:
36   local:
37     dataDir: /var/lib/etcd
38 imageRepository: k8s.gcr.io
39 kind: ClusterConfiguration
40 # 本次部署的版本為 v1.17.4
41 kubernetesVersion: v1.17.4
42 networking:
43   dnsDomain: cluster.local
44   # 添加如下行，指定pod網路的IP地址范圍，因為flannel 就是這個網段
45   podSubnet: 10.244.0.0/16
46   # 默認值即可，無需改變，服務VIP使用可選的IP地址范圍，默認10.96.0.0/12
47   serviceSubnet: 10.96.0.0/12
48 scheduler: {}
49 ---
50 # 添加如下配置段，調度方式從默認改為ipvs方式【如果上面初始化沒有做ipvs，那么這段就不需要】
51 apiVersion: kubeproxy.config.k8s.io/v1alpha1
52 kind: KubeProxyConfiguration
53 featureGates:
54   SupportIPVSProxyMode: true
55 mode: ipvs

相關閱讀

1、基于kubeadm快速部署kubernetes K8S V1.17.4集群-無坑完整版

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