k8s1.13.0二进制部署-node节点（四）

Master apiserver启用TLS认证后，Node节点kubelet组件想要加入集群，必须使用CA签发的有效证书才能与apiserver通信，当Node节点很多时，签署证书是一件很繁琐的事情，因此有了TLS Bootstrapping机制，kubelet会以一个低权限用户自动向apiserver申请证书，kubelet的证书由apiserver动态签署。认证大致工作流程如图所示：

准备二进制文件

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

创建角色绑定

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

创建 kubelet bootstrapping kubeconfig 文件

# 设置集群参数
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

# 设置客户端认证参数
kubectl config set-credentials kubelet-bootstrap 
  --token=${BOOTSTRAP_TOKEN} 
  --kubeconfig=bootstrap.kubeconfig

# 设置上下文参数
kubectl config set-context default 
  --cluster=kubernetes 
  --user=kubelet-bootstrap 
  --kubeconfig=bootstrap.kubeconfig

# 设置默认上下文
kubectl config use-context default --kubeconfig=bootstrap.kubeconfig

将bootstrap.kubeconfig文件拷贝到node节点

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

创建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"

参数说明：

--hostname-override 在集群中显示的主机名 --kubeconfig 指定kubeconfig文件位置，会自动生成 --bootstrap-kubeconfig 指定刚才生成的bootstrap.kubeconfig文件 --cert-dir 颁发证书存放位置 --pod-infra-container-image 管理Pod网络的镜像

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

创建kubelet系统服务

[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

启动kubelet

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

查看csr请求

[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 证书请求

[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已经加入集群

[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

创建 kube-proxy 证书请求

[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"
    }
  ]
}

生成证书

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

将证书分发到node节点

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

创建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

分发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/

创建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"

创建kube-proxy系统服务

[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

启动kube-proxy

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

运行一个测试示例

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

访问部署的nginx

查看访问日志

[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状态

[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