配置創建證書

我們將使用 CloudFlare's PKI 工具 cfssl 來配置 PKI Infrastructure，然後使用它去創建 Certificate Authority（CA）， 併爲 etcd、kube-apiserver、kubelet 以及 kube-proxy 創建 TLS 證書。

Certificate Authority

本節創建用於生成其他 TLS 證書的 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 憑證簽發請求文件:

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 憑證和私鑰:

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

結果將生成以下兩個文件：

ca-key.pem
ca.pem

client 與 server 憑證

本節將創建用於 Kubernetes 組件的 client 與 server 憑證，以及一個用於 Kubernetes admin 用戶的 client 憑證。

Admin 客戶端憑證

創建 admin client 憑證簽發請求文件:

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

創建 admin client 憑證和私鑰:

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

結果將生成以下兩個文件

admin-key.pem
admin.pem

Kubelet 客戶端憑證

Kubernetes 使用 special-purpose authorization mode（被稱作 Node Authorizer）授權來自 Kubelet 的 API 請求。爲了通過 Node Authorizer 的授權, Kubelet 必須使用一個署名爲 system:node:<nodeName> 的憑證來證明它屬於 system:nodes 用戶組。本節將會給每臺 worker 節點創建符合 Node Authorizer 要求的憑證。

給每臺 worker 節點創建憑證和私鑰：

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

結果將產生以下幾個文件：

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

Kube-controller-manager 客戶端憑證

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

結果將產生以下幾個文件：

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

Kube-proxy 客戶端憑證

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

結果將產生以下兩個文件：

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

kube-scheduler 證書

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

結果將產生以下兩個文件：

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

Kubernetes API Server 證書

爲了保證客戶端與 Kubernetes API 的認證，Kubernetes API Server 憑證 中必需包含 kubernetes-the-hard-way 的靜態 IP 地址。

首先查詢 kubernetes-the-hard-way 的靜態 IP 地址:

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

KUBERNETES_HOSTNAMES=kubernetes,kubernetes.default,kubernetes.default.svc,kubernetes.default.svc.cluster,kubernetes.svc.cluster.local

創建 Kubernetes API Server 憑證簽發請求文件:

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

創建 Kubernetes API Server 憑證與私鑰:

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_HOSTNAMES} \
  -profile=kubernetes \
  kubernetes-csr.json | cfssljson -bare kubernetes

結果產生以下兩個文件:

kubernetes-key.pem
kubernetes.pem

Service Account 證書

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

結果將生成以下兩個文件

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

分發客戶端和服務器證書

將客戶端憑證以及私鑰複製到每個工作節點上:

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

將服務器憑證以及私鑰複製到每個控制節點上:

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-proxy、kube-controller-manager、kube-scheduler 和 kubelet 客戶端憑證將會在下一節中用來創建客戶端簽發請求文件。

下一步：配置和生成 Kubernetes 配置文件。