kubernetes怎么更新过期证书？

环境介绍：

#centos7.7#kubernetes 1.16.0

#Step 1：查看证书过期时间（一年有效期）

openssl x509 -in /etc/kubernetes/pki/apiserver.crt -noout -text |grep ' Not '            Not Before: May 24 03:31:50 2019 GMT            Not After : May 23 03:31:50 2020 GMT

#Step 2：下载1.16.0源码

# 下载kubernetes v1.16.0源码，修改关键部分代码的证书生产有效期# github下载源码：https://github.com/kubernetes/kubernetes# 到release下载想到的版本源码，这里我下载v1.16.0

# step 3：解压并且修改源代码
查看网上的资料主要有两个地方需要修改

vim ./staging/src/k8s.io/client-go/util/cert/cert.go# 这个方法里面NotAfter:              now.Add(duration365d * 10).UTC()# 默认有效期就是10年，改成50年func NewSelfSignedCACert(cfg Config, key crypto.Signer) (*x509.Certificate, error) {        now := time.Now()        tmpl := x509.Certificate{                SerialNumber: new(big.Int).SetInt64(0),                Subject: pkix.Name{                        CommonName:   cfg.CommonName,                        Organization: cfg.Organization,                },                NotBefore:             now.UTC(),                // NotAfter:              now.Add(duration365d * 10).UTC(),                NotAfter:              now.Add(duration365d * 50).UTC(),                KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,                BasicConstraintsValid: true,                IsCA:                  true,        }        certDERBytes, err := x509.CreateCertificate(cryptorand.Reader, &tmpl, &tmpl, key.Public(), key)        if err != nil {                return nil, err        }        return x509.ParseCertificate(certDERBytes)}docker run --rm -it -v /root/kubernetes-1.16.0:/go/src/k8s.io/kubernetes \mirrorgooglecontainers/kube-cross:v1.12.10-1 bashvim cmd/kubeadm/app/util/pkiutil/pki_helpers.go# 这个方法里面看到NotAfter:     time.Now().Add(kubeadmconstants.CertificateValidity).UTC()# 参数里面是一个常量kubeadmconstants.CertificateValidity# 所以这里可以不修改，我去看看源码能不能找到这个常量的赋值位置#func NewSignedCert(cfg *certutil.Config, key crypto.Signer, caCert *x509.Certificate, caKey crypto.Signer) (*x509.Certificate, error) {        serial, err := cryptorand.Int(cryptorand.Reader, new(big.Int).SetInt64(math.MaxInt64))#        if err != nil {#                return nil, err#        }       #        if len(cfg.CommonName) == 0 {#                return nil, errors.New("must specify a CommonName")#        }       #        if len(cfg.Usages) == 0 {#                return nil, errors.New("must specify at least one ExtKeyUsage")#        }       #        #        certTmpl := x509.Certificate{#                Subject: pkix.Name{#                        CommonName:   cfg.CommonName,#                        Organization: cfg.Organization,#                },      #                DNSNames:     cfg.AltNames.DNSNames,#                IPAddresses:  cfg.AltNames.IPs,#                SerialNumber: serial,#                NotBefore:    caCert.NotBefore,#                NotAfter:     time.Now().Add(kubeadmconstants.CertificateValidity).UTC(),#                KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,#                ExtKeyUsage:  cfg.Usages,#        }       #        certDERBytes, err := x509.CreateCertificate(cryptorand.Reader, &certTmpl, caCert, key.Public(), caKey)#        if err != nil {#                return nil, err#        }       #        return x509.ParseCertificate(certDERBytes)#} 结果在这里找到kubeadmconstants.CertificateValidity的定义vim ./cmd/kubeadm/app/constants/constants.go// 就是这个常量定义CertificateValidity，我改成*50年const (        // KubernetesDir is the directory Kubernetes owns for storing various configuration files        KubernetesDir = "/etc/kubernetes"        // ManifestsSubDirName defines directory name to store manifests        ManifestsSubDirName = "manifests"        // TempDirForKubeadm defines temporary directory for kubeadm        // should be joined with KubernetesDir.        TempDirForKubeadm = "tmp"        // CertificateValidity defines the validity for all the signed certificates generated by kubeadm        // CertificateValidity = time.Hour * 24 * 365        CertificateValidity = time.Hour * 24 * 365 * 50        // CACertAndKeyBaseName defines certificate authority base name        CACertAndKeyBaseName = "ca"        // CACertName defines certificate name        CACertName = "ca.crt"        // CAKeyName defines certificate name        CAKeyName = "ca.key"源代码改好了，接下来就是编译kubeadm了

#Step 4：编译kubeadm

刚开始尝试服务器安装yum -y install go环境，执行make方法编译，发现特别慢，而且编译显示的内容也不对（get "gotest.tools/gotestsum":found meta tag get.metaImport{...}等内容）,(也可能是golang版本是13不支持的原因但是没有测试)只能尝试下载容器，在容器里面编译，通过网上找资料，发现官网原来有提供一个k8s.gcr.io/kube-cross的容器用于对代码做编译。
由于我不能***，如果不能***的用户，到https://hub.docker.com搜索 kube-cross关键字，我找了一个版本比较新的mirrorgooglecontainers/kube-cross:v1.12.10-1镜像，v1.12.10-1应该就是镜像里面go环境的版本。

注：在使用mirrorgooglecontainers/kube-cross:v1.12.10-1编译之前，我试过下载一个go版本是v.1.11.x的镜像，编译会报错，大概意思是我下载的kubernetes源码必须用v1.12.x才能编译。

拉取镜像docker pull mirrorgooglecontainers/kube-cross:v1.12.10-1# 运行容器，并进入到容器内部docker run --rm -it -v 你修改源码后的kubernetes根目录:/go/src/k8s.io/kubernetes \mirrorgooglecontainers/kube-cross:v1.12.10-1 bash#例如我的源代码放到了/root/kubernetes-1.16.0下docker run --rm -it -v /root/kubernetes-1.16.0:/go/src/k8s.io/kubernetes \mirrorgooglecontainers/kube-cross:v1.12.10-1 bash# cd到容器内部的挂载路径，可以ls -al查看一下里面的文件是不是主机挂载目录的源码文件cd /go/src/k8s.io/kubernetes# 编译kubeadm, 这里主要编译kubeadm 即可make all WHAT=cmd/kubeadm GOFLAGS=-v#部分编译过程节选，用make编译不出现以下过程的可能是出问题了#k8s.io/kubernetes/vendor/k8s.io/legacy-cloud-providers/vsphere/vclib/diskmanagers#k8s.io/kubernetes/vendor/k8s.io/legacy-cloud-providers/vsphere#k8s.io/kubernetes/vendor/github.com/GoogleCloudPlatform/k8s-cloud-provider/pkg/cloud/mock#k8s.io/kubernetes/vendor/k8s.io/legacy-cloud-providers/gce#k8s.io/kubernetes/pkg/volume/vsphere_volume#k8s.io/kubernetes/pkg/cloudprovider/providers#k8s.io/kubernetes/pkg/volume/gcepd#。。。。。。。。# 编译kubelet# make all WHAT=cmd/kubelet GOFLAGS=-v# 编译kubectl# make all WHAT=cmd/kubectl GOFLAGS=-v#编译完产物在 _output/bin/kubeadm 目录下，#其中bin是使用了软连接#真实路径是_output/local/bin/linux/amd64/kubeadm编译成功后，可以退出容器，能看到挂载路径中已经有编译好的kubeadm路径./_output/local/bin/linux/amd64/kubeadm#例：/root/kubernetes-1.16.0/_output/local/bin/linux/amd64

#Step 5：替换掉正在使用的kubeadm

cp /usr/bin/kubeadm /usr/bin/kubeadm.bakcp _output/local/bin/linux/amd64/kubeadm /usr/bin/kubeadm

#Step 6：执行命令更新证书

可以先备份证书，证书在/etc/kubernetes/pki，我这里就不备份了1、检查证书到期时间kubeadm alpha certs check-expirationCERTIFICATE                EXPIRES                  RESIDUAL TIME   EXTERNALLY MANAGEDadmin.conf                 Nov 20, 2069 04:30 UTC   49y             no      apiserver                  Nov 20, 2069 04:30 UTC   49y             no      apiserver-etcd-client      Nov 20, 2069 04:30 UTC   49y             no      apiserver-kubelet-client   Nov 20, 2069 04:30 UTC   49y             no      controller-manager.conf    Nov 20, 2069 04:30 UTC   49y             no      etcd-healthcheck-client    Nov 20, 2069 04:30 UTC   49y             no      etcd-peer                  Nov 20, 2069 04:30 UTC   49y             no      etcd-server                Nov 20, 2069 04:30 UTC   49y             no      front-proxy-client         Nov 20, 2069 04:30 UTC   49y             no      scheduler.conf             Nov 20, 2069 04:30 UTC   49y             no       #使用renew命令即可更新证书，续订全部证书(适用于1.14版本及以上:需要外网环境)#***如果是在断网的情况下必须把有效期改好，再部署设备，否则后期证书过期手动更新证书非常麻烦，切记，切记，切记kubeadm alpha certs renew all #如果你是旧版 kubeadm版本，那么可以用这个脚本来更新你的证书，生成证书默认有效期为10年（3650天），你可以更改脚本里面的CAER_DAYS变量来达到你想要的证书有效期，单位是"天"#下载地址：https://github.com/yuyicai/update-kube-cert/blob/master/README.md#更新kubeadm生成的证书有效期为10年

低版本证书手动更新

#下面为低版本更新仅供参考没有测试#更新证书(适用于1.13版本及以下)#在1.13版本及之前,需要使用kubeadm alpha phase certs来生成新的证书##移动老的证书#注意是: 必须移动，不然会使用现有的证书，不会重新生成!##cd /etc/kubernetes#mkdir -p pki.bak/etcd#mkdir conf.bak#mv pki/apiserver* ./pki.bak/#mv pki/front-proxy-client.* ./pki.bak/#mv pki/etcd/healthcheck-client.* ./pki.bak/etcd/#mv pki/etcd/peer.* ./pki.bak/etcd/#mv pki/etcd/server.* ./pki.bak/etcd/#mv ./admin.conf ./conf.bak/#mv ./kubelet.conf ./conf.bak/#mv ./controller-manager.conf ./conf.bak/#mv ./scheduler.conf ./conf.bak/#注意ca的不动!##生成新的证书#建议不要重新生成ca证书，因为更新了ca证书，集群节点就需要手工操作，才能让集群正常(会涉及重新join)##kubeadm alpha phase certs etcd-healthcheck-client --config /tmp/cluster.yaml##kubeadm alpha phase certs etcd-peer --config /tmp/cluster.yaml##kubeadm alpha phase certs etcd-server --config /tmp/cluster.yaml##kubeadm alpha phase certs front-proxy-client--config /tmp/cluster.yaml##kubeadm alpha phase certs apiserver-etcd-client --config /tmp/cluster.yaml##kubeadm alpha phase certs apiserver-kubelet-client --config /tmp/cluster.yaml##kubeadm alpha phase certs apiserver --config /tmp/cluster.yaml##kubeadm alpha phase certs sa --config /tmp/cluster.yaml#更新kubeconfig文件#生成新的配置文件##kubeadm alpha phase kubeconfig all --apiserver-advertise-address=${MASTER_API_SERVER_IP}#将新生成的admin配置文件覆盖掉原本的admin文件##mv $HOME/.kube/config $HOME/.kube/config.old#cp -i /etc/kubernetes/admin.conf $HOME/.kube/config#chown $(id -u):$(id -g) $HOME/.kube/config#sudo chmod 777 $HOME/.kube/config#完成后重启kube-apiserver,kube-controller,kube-scheduler,etcd这4个容器##如果有多台master，则将第一台生成的相关证书拷贝到其余master即可。##查看证书更新后的使用周期## openssl x509 -in /etc/kubernetes/pki/apiserver.crt -noout -text |grep ' Not '#            Not Before: May 24 03:31:50 2019 GMT#            Not After : Sep  9 02:36:46 2020 GMT##参考#https://kubernetes.io/docs/reference/setup-tools/kubeadm/kubeadm-alpha/

证书更新完毕就不用担心k8s证书过期问题了。