查看集群证书过期情况
kubeadm alpha certs check-expiration
[check-expiration] Reading configuration from the cluster...
[check-expiration] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
CERTIFICATE EXPIRES RESIDUAL TIME CERTIFICATE AUTHORITY EXTERNALLY MANAGED
admin.conf Dec 29, 2021 06:53 UTC 358d no
apiserver Dec 29, 2021 06:53 UTC 358d ca no
apiserver-etcd-client Dec 29, 2021 06:53 UTC 358d etcd-ca no
apiserver-kubelet-client Dec 29, 2021 06:53 UTC 358d ca no
controller-manager.conf Dec 29, 2021 06:53 UTC 358d no
etcd-healthcheck-client Dec 29, 2021 06:53 UTC 358d etcd-ca no
etcd-peer Dec 29, 2021 06:53 UTC 358d etcd-ca no
etcd-server Dec 29, 2021 06:53 UTC 358d etcd-ca no
front-proxy-client Dec 29, 2021 06:53 UTC 358d front-proxy-ca no
scheduler.conf Dec 29, 2021 06:53 UTC 358d no
CERTIFICATE AUTHORITY EXPIRES RESIDUAL TIME EXTERNALLY MANAGED
ca Dec 23, 2029 11:49 UTC 8y no
etcd-ca Dec 23, 2029 11:49 UTC 8y no
front-proxy-ca Dec 23, 2029 11:49 UTC 8y no
查看根CA证书的有效期
cd /etc/kubernetes/pki
# 当前证书是10年的证书,可以直接生成, 如果和上面`EXPIRES` 日期是一样的是不适用
ls | grep ca.crt | xargs -I {} openssl x509 -text -in {} | grep "Not After"
Not After : Dec 23 11:49:43 2029 GMT
Not After : Dec 23 11:49:44 2029 GMT
查看证书目录结构
kubelet 上一般不会明确指定服务端证书, 而是只指定 ca 根证书, 让 kubelet 根据本地主机信息自动生成服务端证书并保存到配置的cert-dir文件夹中。
Kubernetes 集群根证书
== /etc/kubernetes/pki/ca.crt 根证书 == == /etc/kubernetes/pki/ca.key 根证书 ==
其他证书均为根证书签发
kube-apiserver 组件持有的服务端证书 /etc/kubernetes/pki/apiserver.crt /etc/kubernetes/pki/apiserver.key
-
kubelet 组件持有的客户端证书
/etc/kubernetes/pki/apiserver-kubelet-client.crt
/etc/kubernetes/pki/apiserver-kubelet-client.key
汇聚层(aggregator)证书
== /etc/kubernetes/pki/front-proxy-ca.crt ==
== /etc/kubernetes/pki/front-proxy-ca.key ==
-
代理端使用的客户端证书, 用作代用户与 kube-apiserver 认证
/etc/kubernetes/pki/front-proxy-client.crt
/etc/kubernetes/pki/front-proxy-client.key
etcd 集群根证书
== /etc/kubernetes/pki/etcd/ca.crt ==
== /etc/kubernetes/pki/etcd/ca.key ==
etcd server 持有的服务端证书 /etc/kubernetes/pki/etcd/server.crt /etc/kubernetes/pki/etcd/server.key
peer 集群中节点互相通信使用的客户端证书 /etc/kubernetes/pki/etcd/peer.crt /etc/kubernetes/pki/etcd/peer.key
pod 中定义 Liveness 探针使用的客户端证书 /etc/kubernetes/pki/etcd/healthcheck-client.crt /etc/kubernetes/pki/etcd/healthcheck-client.key
-
配置在 kube-apiserver 中用来与 etcd server 做双向认证的客户端证书
/etc/kubernetes/pki/apiserver-etcd-client.crt
/etc/kubernetes/pki/apiserver-etcd-client.key
Serveice Account秘钥
== /etc/kubernetes/pki/sa.key ==
== /etc/kubernetes/pki/sa.pub ==
这组的密钥对儿仅提供给 kube-controller-manager 使用. kube-controller-manager 通过 sa.key 对 token 进行签名, master 节点通过公钥 sa.pub 进行签名的验证.
API Server的authenticating环节支持多种身份校验方式：client cert、bearer token、static password auth等，这些方式中有一种方式通过authenticating（Kubernetes API Server会逐个方式尝试），那么身份校验就会通过。一旦API Server发现client发起的request使用的是service account token的方式，API Server就会自动采用signed bearer token方式进行身份校验。而request就会使用携带的service account token参与验证。该token是API Server在创建service account时用API server启动参数：–service-account-key-file的值签署(sign)生成的。如果–service-account-key-file未传入任何值，那么将默认使用–tls-private-key-file的值，即API Server的私钥（server.key）。
通过authenticating后，API Server将根据Pod username所在的group：system:serviceaccounts和system:serviceaccounts:(NAMESPACE)的权限对其进行authority 和admission control两个环节的处理。在这两个环节中，cluster管理员可以对service account的权限进行细化设置。
# `pki`目录下属于根证书目录
# /etc/kubernetes/pki/ca.crt 根证书
# /etc/kubernetes/pki/ca.key 根证书
#
tree /etc/kubernetes/pki
/etc/kubernetes/pki
├── apiserver.crt
├── apiserver-etcd-client.crt
├── apiserver-etcd-client.key
├── apiserver.key
├── apiserver-kubelet-client.crt
├── apiserver-kubelet-client.key
├── ca.crt
├── ca.key
├── etcd
│ ├── ca.crt
│ ├── ca.key
│ ├── healthcheck-client.crt
│ ├── healthcheck-client.key
│ ├── peer.crt
│ ├── peer.key
│ ├── server.crt
│ └── server.key
├── front-proxy-ca.crt
├── front-proxy-ca.key
├── front-proxy-client.crt
├── front-proxy-client.key
├── sa.key
└── sa.pub备份
# 备份原有证书
cp -rp /etc/kubernetes /etc/kubernetes.bak
# 备份etcd数据目录
cp -r /var/lib/etcd /var/lib/etcd.bak更新证书
生成集群配置的yaml文件
kubeadm config view > /root/kubeadm.yaml
cat /root/kubeadm.yaml
apiServer:
extraArgs:
authorization-mode: Node,RBAC
timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta2
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controllerManager: {}
dns:
type: CoreDNS
etcd:
local:
dataDir: /var/lib/etcd
imageRepository: k8s.gcr.io
kind: ClusterConfiguration
kubernetesVersion: v1.17.0
networking:
dnsDomain: cluster.local
podSubnet: 10.244.0.0/16
serviceSubnet: 10.96.0.0/12
scheduler: {}证书更新使用帮助
kubeadm alpha certs renew --help
Usage:
kubeadm alpha certs renew [flags]
kubeadm alpha certs renew [command]
Available Commands:
admin.conf Renew the certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself
all Renew all available certificates
apiserver Renew the certificate for serving the Kubernetes API
apiserver-etcd-client Renew the certificate the apiserver uses to access etcd
apiserver-kubelet-client Renew the certificate for the API server to connect to kubelet
controller-manager.conf Renew the certificate embedded in the kubeconfig file for the controller manager to use
etcd-healthcheck-client Renew the certificate for liveness probes to healthcheck etcd
etcd-peer Renew the certificate for etcd nodes to communicate with each other
etcd-server Renew the certificate for serving etcd
front-proxy-client Renew the certificate for the front proxy client
scheduler.conf Renew the certificate embedded in the kubeconfig file for the scheduler manager to use更新证书操作
每个master节点都需要执行的, 切记切记
# 更新所有服务的证书,如果不确定可以先更新一个看下结果用检查证书的命令, 上面的用法上有指定单独服务的名称
kubeadm alpha certs renew all --config=/root/kubeadm.yaml
[renew] Reading configuration from the cluster...
[renew] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
certificate embedded in the kubeconfig file for the admin to use and for kubeadm itself renewed
certificate for serving the Kubernetes API renewed
certificate the apiserver uses to access etcd renewed
certificate for the API server to connect to kubelet renewed
certificate embedded in the kubeconfig file for the controller manager to use renewed
certificate for liveness probes to healthcheck etcd renewed
certificate for etcd nodes to communicate with each other renewed
certificate for serving etcd renewed
certificate for the front proxy client renewed
certificate embedded in the kubeconfig file for the scheduler manager to use renewed再次查询证书期限
root @ master ➜ pki kubeadm alpha certs check-expiration
[check-expiration] Reading configuration from the cluster...
[check-expiration] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
CERTIFICATE EXPIRES RESIDUAL TIME CERTIFICATE AUTHORITY EXTERNALLY MANAGED
admin.conf Jan 04, 2022 07:55 UTC 364d no
apiserver Jan 04, 2022 07:55 UTC 364d ca no
apiserver-etcd-client Jan 04, 2022 07:55 UTC 364d etcd-ca no
apiserver-kubelet-client Jan 04, 2022 07:55 UTC 364d ca no
controller-manager.conf Jan 04, 2022 07:55 UTC 364d no
etcd-healthcheck-client Jan 04, 2022 07:55 UTC 364d etcd-ca no
etcd-peer Jan 04, 2022 07:55 UTC 364d etcd-ca no
etcd-server Jan 04, 2022 07:55 UTC 364d etcd-ca no
front-proxy-client Jan 04, 2022 07:55 UTC 364d front-proxy-ca no
scheduler.conf Jan 04, 2022 07:55 UTC 364d no
CERTIFICATE AUTHORITY EXPIRES RESIDUAL TIME EXTERNALLY MANAGED
ca Dec 23, 2029 11:49 UTC 8y no
etcd-ca Dec 23, 2029 11:49 UTC 8y no
front-proxy-ca Dec 23, 2029 11:49 UTC 8y no重启服务
如果上述操作执行之后集群就恢复了,可以不执行如下操作, 但是没有的话,尝试下如下的命令.
命令的作用是直接重启下和证书相关的应用的容器,重新加载证书.
# docker ps |grep -E 'k8s_kube-apiserver|k8s_kube-controller-manager|k8s_kube-scheduler|k8s_etcd_etcd' | awk -F ' ' '{print $1}' |xargs docker restart