k8s1.13.0二進制部署-node節點（四）

Master apiserver啟用TLS認證后，Node節點kubelet組件想要加入集群，必須使用CA簽發的有效證書才能與apiserver通信，當Node節點很多時，簽署證書是一件很繁瑣的事情，因此有了TLS Bootstrapping機制，kubelet會以一個低權限用戶自動向apiserver申請證書，kubelet的證書由apiserver動態簽署。
認證大致工作流程如圖所示：

准備二進制文件

scp kubelet kube-proxy 192.168.0.125:/opt/kubernetes/bin/
scp kubelet kube-proxy 192.168.0.126:/opt/kubernetes/bin/

部署kubelet

創建角色綁定

kubectl create clusterrolebinding kubelet-bootstrap \
  --clusterrole=system:node-bootstrapper \
  --user=kubelet-bootstrap

創建 kubelet bootstrapping kubeconfig 文件

# 設置集群參數
kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=https://192.168.0.130:6443 \
  --kubeconfig=bootstrap.kubeconfig

# 設置客戶端認證參數
kubectl config set-credentials kubelet-bootstrap \
  --token=${BOOTSTRAP_TOKEN} \
  --kubeconfig=bootstrap.kubeconfig

# 設置上下文參數
kubectl config set-context default \
  --cluster=kubernetes \
  --user=kubelet-bootstrap \
  --kubeconfig=bootstrap.kubeconfig

# 設置默認上下文
kubectl config use-context default --kubeconfig=bootstrap.kubeconfig

將bootstrap.kubeconfig文件拷貝到node節點

scp bootstrap.kubeconfig 192.168.0.125:/opt/kubernetes/cfg/
scp bootstrap.kubeconfig 192.168.0.126:/opt/kubernetes/cfg/

創建kubelet配置文件

[root@k8s-node01 ~]# vim /opt/kubernetes/cfg/kubelet

KUBELET_OPTS="--logtostderr=false \
--v=4 \
--log-dir=/opt/kubernetes/log \
--hostname-override=192.168.0.125 \
--kubeconfig=/opt/kubernetes/cfg/kubelet.kubeconfig \
--bootstrap-kubeconfig=/opt/kubernetes/cfg/bootstrap.kubeconfig \
--config=/opt/kubernetes/cfg/kubelet.config \
--cert-dir=/opt/kubernetes/ssl \
--pod-infra-container-image=registry.cn-hangzhou.aliyuncs.com/google-containers/pause-amd64:3.0"

參數說明： 

--hostname-override 在集群中顯示的主機名
--kubeconfig 指定kubeconfig文件位置，會自動生成
--bootstrap-kubeconfig 指定剛才生成的bootstrap.kubeconfig文件
--cert-dir 頒發證書存放位置
--pod-infra-container-image 管理Pod網絡的鏡像

其中/opt/kubernetes/cfg/kubelet.config配置文件如下：

[root@k8s-node01 ~]# vim /opt/kubernetes/cfg/kubelet.config
kind: KubeletConfiguration
apiVersion: kubelet.config.k8s.io/v1beta1
address:
port: 10250
readOnlyPort: 10255
cgroupDriver: cgroupfs
clusterDNS:
- 10.0.0.2
clusterDomain: cluster.local.
failSwapOn: false
authentication:
  anonymous:
    enabled: true

創建kubelet系統服務

[root@k8s-node02 ~]# vim /usr/lib/systemd/system/kubelet.service
[Unit]
Description=Kubernetes Kubelet
After=docker.service
Requires=docker.service

[Service]
EnvironmentFile=/opt/kubernetes/cfg/kubelet
ExecStart=/opt/kubernetes/bin/kubelet $KUBELET_OPTS
Restart=on-failure
KillMode=process

[Install]
WantedBy=multi-user.target

啟動kubelet

systemctl daemon-reload
systemctl enable kubelet
systemctl restart kubelet
systemctl status kubelet

 查看csr請求

[root@k8s-master1 ~]# kubectl get csr
NAME                                                   AGE    REQUESTOR           CONDITION
node-csr-h0XFLgAXsCQvIQdUN5_fHGJbwYJaekO3zzhEK_wDcNY   103s   kubelet-bootstrap   Pending
node-csr-xECZ6WkPvlSzu9fE4CJQlMjPfCxJlUpidvSuKWOGpZE   90s    kubelet-bootstrap   Pending

批准kubelet 的 TLS 證書請求

[root@k8s-master1 ~]# kubectl get csr|grep 'Pending' | awk 'NR>0{print $1}'| xargs kubectl certificate approve
certificatesigningrequest.certificates.k8s.io/node-csr-h0XFLgAXsCQvIQdUN5_fHGJbwYJaekO3zzhEK_wDcNY approved
certificatesigningrequest.certificates.k8s.io/node-csr-xECZ6WkPvlSzu9fE4CJQlMjPfCxJlUpidvSuKWOGpZE approved

查看node已經加入集群

[root@k8s-master1 ~]# kubectl get node
NAME            STATUS   ROLES    AGE   VERSION
192.168.0.125   Ready    <none>   68s   v1.13.0
192.168.0.126   Ready    <none>   69s   v1.13.0

kube-proxy部署

配置kube-proxy使用LVS

yum install -y ipvsadm ipset conntrack

創建 kube-proxy 證書請求

[root@k8s-master1 ssl]# vim kube-proxy-csr.json
{
  "CN": "system:kube-proxy",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "System"
    }
  ]
}

生成證書

cfssl gencert -ca=/opt/kubernetes/ssl/ca.pem \
   -ca-key=/opt/kubernetes/ssl/ca-key.pem \
   -config=/opt/kubernetes/ssl/ca-config.json \
   -profile=kubernetes  kube-proxy-csr.json | cfssljson -bare kube-proxy

將證書分發到node節點

scp kube-proxy*.pem 192.168.0.125:/opt/kubernetes/ssl/
scp kube-proxy*.pem 192.168.0.126:/opt/kubernetes/ssl/

創建kube-proxy kubeconfig文件

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/kubernetes/ssl/ca.pem \
  --embed-certs=true \
  --server=https://192.168.0.130:6443 \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-credentials kube-proxy \
  --client-certificate=kube-proxy.pem \
  --client-key=kube-proxy-key.pem \
  --embed-certs=true \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config set-context default \
  --cluster=kubernetes \
  --user=kube-proxy \
  --kubeconfig=kube-proxy.kubeconfig

kubectl config use-context default --kubeconfig=kube-proxy.kubeconfig

分發kubeconfig配置文件

scp kube-proxy.kubeconfig 192.168.0.125:/opt/kubernetes/cfg/
scp kube-proxy.kubeconfig 192.168.0.126:/opt/kubernetes/cfg/

創建kube-proxy配置文件

[root@k8s-node01 ~]# vim /opt/kubernetes/cfg/kube-proxy

KUBE_PROXY_OPTS="--logtostderr=false \
--v=4 \
--log-dir=/opt/kubernetes/log \
--hostname-override=192.168.0.125 \
--cluster-cidr=10.0.0.0/24 \
--proxy-mode=ipvs \
--ipvs-min-sync-period=5s \
--ipvs-sync-period=5s \
--ipvs-scheduler=rr \
--masquerade-all=true \
--kubeconfig=/opt/kubernetes/cfg/kube-proxy.kubeconfig"

創建kube-proxy系統服務

[root@k8s-node01 ~]# vim /usr/lib/systemd/system/kube-proxy.service
[Unit]
Description=Kubernetes Proxy
After=network.target

[Service]
EnvironmentFile=-/opt/kubernetes/cfg/kube-proxy
ExecStart=/opt/kubernetes/bin/kube-proxy $KUBE_PROXY_OPTS
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target

啟動kube-proxy

systemctl daemon-reload
systemctl enable kube-proxy
systemctl restart kube-proxy
systemctl status kube-proxy

運行一個測試示例

kubectl run nginx --image=nginx --replicas=3
kubectl expose deployment nginx --port=88 --target-port=80 --type=NodePort

查看pod,service

[root@k8s-master1 ~]# kubectl get pod,svc -o wide
NAME                         READY   STATUS              RESTARTS   AGE   IP            NODE            NOMINATED NODE   READINESS GATES
pod/nginx-7cdbd8cdc9-g9658   0/1     ImagePullBackOff    0          51s   172.17.84.2   192.168.0.125   <none>           <none>
pod/nginx-7cdbd8cdc9-wmh46   0/1     ContainerCreating   0          51s   <none>        192.168.0.126   <none>           <none>
pod/nginx-7cdbd8cdc9-zwmxd   0/1     ContainerCreating   0          51s   <none>        192.168.0.126   <none>           <none>

NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)        AGE   SELECTOR
service/kubernetes   ClusterIP   10.0.0.1     <none>        443/TCP        21h   <none>
service/nginx        NodePort    10.0.0.171   <none>        88:48652/TCP   48s   run=nginx

訪問部署的nginx

查看訪問日志

[root@k8s-master1 ~]# kubectl create clusterrolebinding cluster-system-anonymous --clusterrole=cluster-admin --user=system:anonymous
[root@k8s-master1 ~]# kubectl logs nginx-7cdbd8cdc9-g9658
172.17.84.1 - - [18/Dec/2018:01:59:43 +0000] "GET / HTTP/1.1" 200 612 "-" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/69.0.3497.100 Safari/537.36" "-"

查看LVS狀態

[root@k8s-node02 ~]# ipvsadm -L -n
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
-> RemoteAddress:Port Forward Weight ActiveConn InActConn
TCP 127.0.0.1:48652 rr
-> 172.17.34.2:80 Masq 1 0 0
-> 172.17.34.3:80 Masq 1 0 0
-> 172.17.84.2:80 Masq 1 0 0
TCP 172.17.34.0:48652 rr
-> 172.17.34.2:80 Masq 1 0 0
-> 172.17.34.3:80 Masq 1 0 0
-> 172.17.84.2:80 Masq 1 0 0
TCP 172.17.34.1:48652 rr
-> 172.17.34.2:80 Masq 1 0 0
-> 172.17.34.3:80 Masq 1 0 0
-> 172.17.84.2:80 Masq 1 0 0
TCP 192.168.0.126:48652 rr
-> 172.17.34.2:80 Masq 1 0 0
-> 172.17.34.3:80 Masq 1 0 0
-> 172.17.84.2:80 Masq 1 0 0
TCP 10.0.0.1:443 rr
-> 192.168.0.123:6443 Masq 1 0 0
-> 192.168.0.124:6443 Masq 1 0 0
TCP 10.0.0.171:88 rr
-> 172.17.34.2:80 Masq 1 0 0
-> 172.17.34.3:80 Masq 1 0 0
-> 172.17.84.2:80 Masq 1 0 0