kubernetes集群安装指南：客户端安装及各组件认证文件建立

大多状况，证书用于服务安全访问（即https访问）所须要，在kubernetes集群中，若是关闭了匿名访问，开启了集群HTTPS访问以及TLS双向认证；如：worker节点组件HTTPS访问apiserver服务时，Apiserver还须要验证客户端是否合法，此时就须要为worker节点上的组件生成kubeconfig认证文件用于链接apiserver。

1. 基本设置

1.1 变量设置

PACKAGE=kubernetes-server-v1.12.0-linux-amd64.tar.gz
K8S_DOWNLOAD_URL=https://github.com/devops-apps/download/raw/master/kubernetes/$PACKAGE
K8S_CONF_PATH=/etc/k8s/kubernetes
K8S_KUBECONFIG_PATH=/etc/k8s/kubeconfig
KUBE_APISERVER=https://dev-kube-api.mo9.com
BOOTSTRAP_TOKEN=$(head -c 16 /dev/urandom | od -An -t x | tr -d ' ')

1.2 kubectl、kubens工具集安装

sudo wget $K8S_DOWNLOAD_URL -P /root/software
cd $SOFTWARE 
tar -xzfkubernetes-server-v1.12.0-linux-amd64.tar.gz -C ./
cp -fp kubernetes/server/bin/{kubectl,kubens} /usr/local/sbin

1.3 建立认证文件存放目录

if [ ! -d "$K8S_CONF_PATH" ]; then
     mkdir -p $K8S_CONF_PATH
fi

if [ ! -d "$K8S_KUBECONFIG_PATH" ]; then
     mkdir -p $K8S_KUBECONFIG_PATH
fi

2. 建立 TLS Bootstrapping Token

cat > ${K8S_CONF_PATH}/token.csv <<EOF
${BOOTSTRAP_TOKEN},kubelet-bootstrap,10001,"system:kubelet-bootstrap"
EOF

• bootstrapping token文件主要用于为apiserver开启tocken认证而建立，若是没有开启apiserver token认证能够不用建立此文件；

3 kubeconfig文件建立

3.1 建立kube-controller-manager kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=${CA_DIR}/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-controller-manager.kubeconfig

kubectl config set-credentials system:kube-controller-manager \
  --client-certificate=${CA_DIR}/kube-controller-manager.pem \
  --client-key=${CA_DIR}/kube-controller-manager-key.pem \
  --embed-certs=true \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-controller-manager.kubeconfig

kubectl config set-context system:kube-controller-manager \
  --cluster=kubernetes \
  --user=system:kube-controller-manager \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-controller-manager.kubeconfig

kubectl config use-context system:kube-controller-manager \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-controller-manager.kubeconfig

3.2 建立kube-shceduler kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=${CA_DIR}/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-scheduler.kubeconfig

kubectl config set-credentials system:kube-scheduler \
  --client-certificate=${CA_DIR}/kube-scheduler.pem \
  --client-key=${CA_DIR}/kube-scheduler-key.pem \
  --embed-certs=true \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-scheduler.kubeconfig

kubectl config set-context system:kube-scheduler \
  --cluster=kubernetes \
  --user=system:kube-scheduler \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-scheduler.kubeconfig

kubectl config use-context system:kube-scheduler \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-scheduler.kubeconfig

3.3 建立kubelet bootstrapping kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=${CA_DIR}/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/bootstrap.kubeconfig

kubectl config set-credentials kubelet-bootstrap \
  --token=${BOOTSTRAP_TOKEN} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/bootstrap.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes \
  --user=kubelet-bootstrap \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/bootstrap.kubeconfig

kubectl config use-context default \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/bootstrap.kubeconfig

• bootstrapping文件主要用于apiserver给kubelet证书作自动轮转，使用该文件，apiserver会自动给kubelet颁发服务端证书以及证书密钥，从而没必要为kubelet证书

3.4 建立kube-proxy kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=${CA_DIR}/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-proxy.kubeconfig

kubectl config set-credentials kube-proxy \
  --client-certificate=${CA_DIR}/kube-proxy.pem \
  --client-key=${CA_DIR}/kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-proxy.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-proxy \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-proxy.kubeconfig

kubectl config use-context default \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kube-proxy.kubeconfig

3.5 建立kubectl kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=${CA_DIR}/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kubectl.kubeconfig

kubectl config set-credentials admin \
  --client-certificate=${CA_DIR}/admin.pem \
  --client-key=${CA_DIR}/admin-key.pem \
  --embed-certs=true \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kubectl.kubeconfig

kubectl config set-context kubernetes \
  --cluster=kubernetes \
  --user=admin \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kubectl.kubeconfig

kubectl config use-context kubernetes \
  --kubeconfig=${K8S_KUBECONFIG_PATH}/kubectl.kubeconfig

• --certificate-authority：验证 kube-apiserver 证书的根证书；
• --client-certificate、--client-key：刚生成的 admin 证书和私钥，链接 kube-apiserver 时使用；
• --embed-certs=true：将 ca.pem 和 admin.pem 证书内容嵌入到生成的 kubectl.kubeconfig 文件中(不加时，写入的是证书文件路径)；

备注：kubeconfig文件是用于安全链接apiserver服务的认证文件。

4 同步token文件及kubeconfig文件到相应的节点

• master节点：

  cd $K8S_KUBECONFIG_PATH
  ansible master_k8s_vgs -m copy -a \
  "src=kube-controller-manager.kubeconfig dest=$K8S_KUBECONFIG_PATH/ " -b
  ansible master_k8s_vgs -m copy -a \
  "src=kube-scheduler.kubeconfig dest=$K8S_KUBECONFIG_PATH/ " -b

• worker节点

  cd $K8S_KUBECONFIG_PATH
  ansible worker_k8s_vgs -m copy -a \
  "src=bootstrap.kubeconfig dest=$K8S_KUBECONFIG_PATH/ " -b
  ansible worker_k8s_vgs -m copy -a \
  "src=kube-proxy.kubeconfig dest=$K8S_KUBECONFIG_PATH/ " -b

• kubeconfig文件主要用于各组件在经过https访问apiserver时所须要的认证的文件，该文件包括对应组件的服务端证书、证书私钥、ca根证书以及apiserver的访问地址

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建立完kubernetes集群组件相关认证文件后，接下来正式部署kubernetes集群相关组件etcd集群，请参考：kubernetes集群安装指南：etcd集群部署