Kubeadm证书过期时间调整

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kubeadm 默认证书为一年，一年过期后，会导致api service不可用，使用过程中会出现：x509: certificate has expired or is not yet valid

如何进行调整，下面给了两个方案，供大家选择

方案一 通过修改kubeadm 调整证书过期时间

修改代码，调整过期时间

克隆代码：git clone https://github.com/kubernetes/kubernetes.git, 切换到指定的tag或者版本修改vendor/k8s.io/client-go/util/cert/cert.go文件，git diff 对比如下：

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diff --git a/staging/src/k8s.io/client-go/util/cert/cert.go b/staging/src/k8s.io/client-go/util/cert/cert.go
index fb7f5fa..e800962 100644
--- a/staging/src/k8s.io/client-go/util/cert/cert.go
+++ b/staging/src/k8s.io/client-go/util/cert/cert.go
@@ -104,7 +104,7 @@ func NewSignedCert(cfg Config, key *rsa.PrivateKey, caCert *x509.Certificate, ca
                IPAddresses:  cfg.AltNames.IPs,
                SerialNumber: serial,
                NotBefore:    caCert.NotBefore,
-               NotAfter:     time.Now().Add(duration365d).UTC(),
+               NotAfter:     time.Now().Add(duration365d * 10).UTC(),
                KeyUsage:     x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature,
                ExtKeyUsage:  cfg.Usages,
        }
@@ -149,7 +149,7 @@ func GenerateSelfSignedCertKey(host string, alternateIPs []net.IP, alternateDNS
                        CommonName: fmt.Sprintf("%s-ca@%d", host, time.Now().Unix()),
                },
                NotBefore: time.Now(),
-               NotAfter:  time.Now().Add(time.Hour * 24 * 365),
+               NotAfter:  time.Now().Add(time.Hour * 24 * 3650),

                KeyUsage:              x509.KeyUsageKeyEncipherment | x509.KeyUsageDigitalSignature | x509.KeyUsageCertSign,
                BasicConstraintsValid: true,

编译代码

编译环境我已经做了对应的1.11.5、1.12.3、1.13.0、1.13.2、1.13.4、1.14.1、1.15.3，已上传到docker hub 上，大家可下载使用，地址如下：

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docker pull icyboy/k8s_build:v1.11.5  # 基于 golang:1.10.3
docker pull icyboy/k8s_build:v1.12.3  # 基于 golang:1.10.4 
docker pull icyboy/k8s_build:v1.13.0  # 基于 golang:1.11.2
docker pull icyboy/k8s_build:v1.13.2  # 基于 golang:1.11.4
docker pull icyboy/k8s_build:v1.13.4  # 基于 golang:1.11.5
docker pull icyboy/k8s_build:v1.14.1  # 基于 golang:1.12.2
docker pull icyboy/k8s_build:v1.15.3  # 基于 golang:1.12.9
docker pull icyboy/k8s_build:v1.16.0  # 基于 golang:1.12.9
docker pull icyboy/k8s_build:v1.16.3  # 基于 golang:1.12.12
docker pull icyboy/k8s_build:v1.17.0  # 基于 golang:1.13.4
docker pull icyboy/k8s_build:v1.17.1  # 基于 golang:1.13.5
docker pull icyboy/k8s_build:v1.17.3  # 基于 golang:1.13.6

编译

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docker run --rm -v 你修改后的代码目录:/go/src/k8s.io/kubernetes -it icyboy/k8s_build:v1.11.5 bash

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

# 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
#将kubeadm 文件拷贝出来，替换系统中的kubeadm

对应的kubeadm 文件我也编译好后放到百度云中，大家可放心下载使用，可通过kubeadm version 查看对应的版本信息和官方的进行比对

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#编译过后的
kubeadm version: &version.Info{Major:"1", Minor:"11+", GitVersion:"v1.11.5-dirty", GitCommit:"753b2dbc622f5cc417845f0ff8a77f539a4213ea", GitTreeState:"dirty", BuildDate:"2018-12-07T05:58:18Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}

#官方的
kubeadm version: &version.Info{Major:"1", Minor:"11", GitVersion:"v1.11.5", GitCommit:"753b2dbc622f5cc417845f0ff8a77f539a4213ea", GitTreeState:"clean", BuildDate:"2018-11-26T14:38:30Z", GoVersion:"go1.10.3", Compiler:"gc", Platform:"linux/amd64"}

kubeadm 下载地址：https://pan.baidu.com/s/1PplHyDkYDTusx46j9uHwDA
提取码：dy6f

替换证书

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#用新的kubeadm 替换官方的kubeadm
chmod +x kubeadm && \cp -f kubeadm /usr/bin

#备份原有的证书
mv /etc/kubernetes/pki /etc/kubernetes/pki.old

#生成新的证书，kubeadm.yaml 指定你自己服务器上的
kubeadm alpha phase certs all --config  ~/kubeadm.yaml

#备份原有的conf文件
mv /etc/kubernetes/*conf /etc/kubernetes/*conf-old

#根据新证书重新生成新的配置文件
kubeadm alpha phase kubeconfig all --config ~/kubeadm.yaml

#替换老的config文件
\cp -f /etc/kubernetes/admin.conf ~/.kube/config

验证

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cd /etc/kubernetes/pki
openssl x509 -in apiserver-etcd-client.crt -text -noout
#Certificate:
#    Data:
#        Version: 3 (0x2)
#        Serial Number: 2755977466456048186 (0x263f32e76918023a)
#    Signature Algorithm: sha256WithRSAEncryption
#        Issuer: CN=kubernetes
#        Validity
#            Not Before: Dec  7 09:33:32 2018 GMT
             Not After : Dec  4 09:33:32 2028 GMT  #这里变成10年了
#        Subject: O=system:masters, CN=kube-apiserver-etcd-client
#        Subject Public Key Info:
#        ....

# 批量验证证书
for crt in $(find /etc/kubernetes/pki/ -name "*.crt"); do openssl x509 -in $crt -noout -dates; done

方案二 启用自动轮换kubelet 证书

kubelet证书分为server和client两种， k8s 1.9默认启用了client证书的自动轮换，但server证书自动轮换需要用户开启

增加 kubelet 参数

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# 在/etc/systemd/system/kubelet.service.d/10-kubeadm.conf 增加如下参数
Environment="KUBELET_EXTRA_ARGS=--feature-gates=RotateKubeletServerCertificate=true"

增加 controller-manager 参数

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# 在/etc/kubernetes/manifests/kube-controller-manager.yaml 添加如下参数
  - command:
    - kube-controller-manager
    - --experimental-cluster-signing-duration=87600h0m0s
    - --feature-gates=RotateKubeletServerCertificate=true
    - ....

创建 rbac 对象

创建rbac对象，允许节点轮换kubelet server证书：

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cat > ca-update.yaml << EOF
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRole
metadata:
  annotations:
    rbac.authorization.kubernetes.io/autoupdate: "true"
  labels:
    kubernetes.io/bootstrapping: rbac-defaults
  name: system:certificates.k8s.io:certificatesigningrequests:selfnodeserver
rules:
- apiGroups:
  - certificates.k8s.io
  resources:
  - certificatesigningrequests/selfnodeserver
  verbs:
  - create
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: kubeadm:node-autoapprove-certificate-server
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: system:certificates.k8s.io:certificatesigningrequests:selfnodeserver
subjects:
- apiGroup: rbac.authorization.k8s.io
  kind: Group
  name: system:nodes
EOF

kubectl create –f ca-update.yaml

如果证书已经过期，如何进行重新签发证书

针对kubeadm 1.13.x 及以上处理

准备kubeadm.conf 配置文件一份
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apiVersion: kubeadm.k8s.io/v1beta1
kind: ClusterConfiguration
kubernetesVersion: v1.14.1 #-->这里改成你集群对应的版本
imageRepository: registry.cn-hangzhou.aliyuncs.com/google_containers 
#这里使用国内的镜像仓库，否则在重新签发的时候会报错：could not fetch a Kubernetes version from the internet: unable to get URL "https://dl.k8s.io/release/stable-1.txt"
重新签发命令
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kubeadm alpha certs renew all --config=/root/kubeadm.conf

运行如上命令会重新生成以下证书
#-- /etc/kubernetes/pki/apiserver.key
#-- /etc/kubernetes/pki/apiserver.crt

#-- /etc/kubernetes/pki/apiserver-etcd-client.key
#-- /etc/kubernetes/pki/apiserver-etcd-client.crt

#-- /etc/kubernetes/pki/apiserver-kubelet-client.key
#-- /etc/kubernetes/pki/apiserver-kubelet-client.crt

#-- /etc/kubernetes/pki/front-proxy-client.key
#-- /etc/kubernetes/pki/front-proxy-client.crt

#-- /etc/kubernetes/pki/etcd/healthcheck-client.key
#-- /etc/kubernetes/pki/etcd/healthcheck-client.crt

#-- /etc/kubernetes/pki/etcd/peer.key
#-- /etc/kubernetes/pki/etcd/peer.crt

#-- /etc/kubernetes/pki/etcd/server.key
#-- /etc/kubernetes/pki/etcd/server.crt
更新/etc/kubernetes/*.conf文件
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#备份删除旧的/etc/kubernetes/*.conf文件
mkdir /etc/kubernetes/old-conf  
mv /etc/kubernetes/*.conf /etc/kubernetes/old-conf

#生成新的conf文件
kubeadm init phase kubeconfig all --config=/root/kubeadm.conf

#运行如上命令会重新生成以下conf文件
#-- /etc/kubernetes/admin.conf
#-- /etc/kubernetes/controller-manager.conf
#-- /etc/kubernetes/kubelet.conf
#-- /etc/kubernetes/scheduler.conf
完成后重启kube-apiserver,kube-controller,kube-scheduler,etcd这4个容器,最后覆盖config文件
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cp -i /etc/kubernetes/admin.conf $HOME/.kube/config

针对kubeadm 1.13.0（不包含1.13.0） 以下处理

移动证书和配置【注意！必须移动，不然会使用现有的证书，不会重新生成】
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cd /etc/kubernetes
mkdir ./pki_bak
mkdir ./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/
创建证书
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kubeadm alpha phase certs all --apiserver-advertise-address=${MASTER_API_SERVER_IP} --apiserver-cert-extra-sans=主机内网ip,主机公网ip

运行如上命令会重新生成以下证书
#-- /etc/kubernetes/pki/apiserver.key
#-- /etc/kubernetes/pki/apiserver.crt

#-- /etc/kubernetes/pki/apiserver-etcd-client.key
#-- /etc/kubernetes/pki/apiserver-etcd-client.crt

#-- /etc/kubernetes/pki/apiserver-kubelet-client.key
#-- /etc/kubernetes/pki/apiserver-kubelet-client.crt

#-- /etc/kubernetes/pki/front-proxy-client.key
#-- /etc/kubernetes/pki/front-proxy-client.crt

#-- /etc/kubernetes/pki/etcd/healthcheck-client.key
#-- /etc/kubernetes/pki/etcd/healthcheck-client.crt

#-- /etc/kubernetes/pki/etcd/peer.key
#-- /etc/kubernetes/pki/etcd/peer.crt

#-- /etc/kubernetes/pki/etcd/server.key
#-- /etc/kubernetes/pki/etcd/server.crt

不移动证书会有如下提示
#[certificates] Using the existing apiserver certificate and key.
#[certificates] Using the existing apiserver-kubelet-client certificate and key.
#[certificates] Using the existing front-proxy-client certificate and key.
#[certificates] Using the existing etcd/server certificate and key.
#[certificates] Using the existing etcd/peer certificate and key.
#[certificates] Using the existing etcd/healthcheck-client certificate and key.
#[certificates] Using the existing apiserver-etcd-client certificate and key.
#[certificates] valid certificates and keys now exist in "/etc/kubernetes/pki"
#[certificates] Using the existing sa key.
生成新配置文件
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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
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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 644 $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。

离线一键安装包

k8s 离线一键安装包教程&&地址：一键安装

kubeadm 1.14 证书调整教程

教程地址

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-------------本文结束感谢您的阅读-------------

本文标题:Kubeadm证书过期时间调整

文章作者:icyboy

发布时间:2018年12月11日 - 20:00

最后更新:2020年09月02日 - 11:33

原始链接:http://team.jiunile.com/blog/2018/12/k8s-kubeadm-ca-upgdate.html

许可协议: 署名-非商业性使用-禁止演绎 4.0 国际 转载请保留原文链接及作者。

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