配置创建证书

我们将使用 CloudFlare's PKI 工具 cfssl 来配置 PKI Infrastructure,然后使用它去创建 Certificate Authority(CA), 并为 etcd、kube-apiserver、kubelet 以及 kube-proxy 创建 TLS 证书。

Certificate Authority

本节创建用于生成其他 TLS 证书的 Certificate Authority。

新建 CA 配置文件

cat > ca-config.json <<EOF
{
"signing": {
"default": {
"expiry": "8760h"
},
"profiles": {
"kubernetes": {
"usages": ["signing", "key encipherment", "server auth", "client auth"],
"expiry": "8760h"
}
}
}
}
EOF

新建 CA 凭证簽发请求文件:

cat > ca-csr.json <<EOF
{
"CN": "Kubernetes",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "Kubernetes",
"OU": "CA",
"ST": "Oregon"
}
]
}
EOF

生成 CA 凭证和私钥:

cfssl gencert -initca ca-csr.json | cfssljson -bare ca

结果将生成以下两个文件:

ca-key.pem
ca.pem

client 与 server 凭证

本节将创建用于 Kubernetes 组件的 client 与 server 凭证,以及一个用于 Kubernetes admin 用户的 client 凭证。

Admin 客户端凭证

创建 admin client 凭证簽发请求文件:

cat > admin-csr.json <<EOF
{
"CN": "admin",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "system:masters",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF

创建 admin client 凭证和私钥:

cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-profile=kubernetes \
admin-csr.json | cfssljson -bare admin

结果将生成以下两个文件

admin-key.pem
admin.pem

Kubelet 客户端凭证

Kubernetes 使用 special-purpose authorization mode(被称作 Node Authorizer)授权来自 Kubelet 的 API 请求。为了通过 Node Authorizer 的授权, Kubelet 必须使用一个署名为 system:node:<nodeName> 的凭证来证明它属于 system:nodes 用户组。本节将会给每台 worker 节点创建符合 Node Authorizer 要求的凭证。

给每台 worker 节点创建凭证和私钥:

for instance in worker-0 worker-1 worker-2; do
cat > ${instance}-csr.json <<EOF
{
"CN": "system:node:${instance}",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "system:nodes",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF
EXTERNAL_IP=$(gcloud compute instances describe ${instance} \
--format 'value(networkInterfaces[0].accessConfigs[0].natIP)')
INTERNAL_IP=$(gcloud compute instances describe ${instance} \
--format 'value(networkInterfaces[0].networkIP)')
cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-hostname=${instance},${EXTERNAL_IP},${INTERNAL_IP} \
-profile=kubernetes \
${instance}-csr.json | cfssljson -bare ${instance}
done

结果将产生以下几个文件:

worker-0-key.pem
worker-0.pem
worker-1-key.pem
worker-1.pem
worker-2-key.pem
worker-2.pem

Kube-controller-manager 客户端凭证

cat > kube-controller-manager-csr.json <<EOF
{
"CN": "system:kube-controller-manager",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "system:kube-controller-manager",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF
cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-profile=kubernetes \
kube-controller-manager-csr.json | cfssljson -bare kube-controller-manager

结果将产生以下几个文件:

kube-controller-manager-key.pem
kube-controller-manager.pem

Kube-proxy 客户端凭证

cat > kube-proxy-csr.json <<EOF
{
"CN": "system:kube-proxy",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "system:node-proxier",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF
cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-profile=kubernetes \
kube-proxy-csr.json | cfssljson -bare kube-proxy

结果将产生以下两个文件:

kube-proxy-key.pem
kube-proxy.pem

kube-scheduler 证书

cat > kube-scheduler-csr.json <<EOF
{
"CN": "system:kube-scheduler",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "system:kube-scheduler",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF
cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-profile=kubernetes \
kube-scheduler-csr.json | cfssljson -bare kube-scheduler

结果将产生以下两个文件:

kube-scheduler-key.pem
kube-scheduler.pem

Kubernetes API Server 证书

为了保证客户端与 Kubernetes API 的认证,Kubernetes API Server 凭证 中必需包含 kubernetes-the-hard-way 的静态 IP 地址。

首先查询 kubernetes-the-hard-way 的静态 IP 地址:

KUBERNETES_PUBLIC_ADDRESS=$(gcloud compute addresses describe kubernetes-the-hard-way \
--region $(gcloud config get-value compute/region) \
--format 'value(address)')

创建 Kubernetes API Server 凭证簽发请求文件:

cat > kubernetes-csr.json <<EOF
{
"CN": "kubernetes",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "Kubernetes",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF

创建 Kubernetes API Server 凭证与私钥:

cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-hostname=10.32.0.1,10.240.0.10,10.240.0.11,10.240.0.12,${KUBERNETES_PUBLIC_ADDRESS},127.0.0.1,kubernetes.default \
-profile=kubernetes \
kubernetes-csr.json | cfssljson -bare kubernetes

结果产生以下两个文件:

kubernetes-key.pem
kubernetes.pem

Service Account 证书

cat > service-account-csr.json <<EOF
{
"CN": "service-accounts",
"key": {
"algo": "rsa",
"size": 2048
},
"names": [
{
"C": "US",
"L": "Portland",
"O": "Kubernetes",
"OU": "Kubernetes The Hard Way",
"ST": "Oregon"
}
]
}
EOF
cfssl gencert \
-ca=ca.pem \
-ca-key=ca-key.pem \
-config=ca-config.json \
-profile=kubernetes \
service-account-csr.json | cfssljson -bare service-account

结果将生成以下两个文件

service-account-key.pem
service-account.pem

分发客户端和服务器证书

将客户端凭证以及私钥复制到每个工作节点上:

for instance in worker-0 worker-1 worker-2; do
gcloud compute scp ca.pem ${instance}-key.pem ${instance}.pem ${instance}:~/
done

将服务器凭证以及私钥复制到每个控制节点上:

for instance in controller-0 controller-1 controller-2; do
gcloud compute scp ca.pem ca-key.pem kubernetes-key.pem kubernetes.pem \
service-account-key.pem service-account.pem ${instance}:~/
done

kube-proxykube-controller-managerkube-schedulerkubelet 客户端凭证将会在下一节中用来创建客户端簽发请求文件。

下一步:配置和生成 Kubernetes 配置文件