手动搭建k8s-1.16.6高可用集群之部署worker节点-部署kube-proxy组件

kube-proxy 运行在所有 worker 节点上，它监听 apiserver 中 service 和 endpoint 的变化情况，创建路由规则以提供服务 IP 和负载均衡功能。

本文档讲解部署 ipvs 模式的 kube-proxy 过程。

注意：如果没有特殊指明，本文档的所有操作均在 k8s-01 节点上执行，然后远程分发文件和执行命令。

下载和分发在部署master节点时已经做过，依赖包也在work节点中安装了，可以直接进入配置步骤。

一、创建 kube-proxy 证书

cd /opt/k8s/work

cat > kube-proxy-csr.json <<EOF
{
  "CN": "system:kube-proxy",
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "BeiJing",
      "L": "BeiJing",
      "O": "k8s",
      "OU": "opsnull"
    }
  ]
}
EOF

• CN：指定该证书的 User 为 system:kube-proxy；
• 预定义的 RoleBinding system:node-proxier 将User system:kube-proxy 与 Role system:node-proxier 绑定，该 Role 授予了调用 kube-apiserver Proxy 相关 API 的权限；
• 该证书只会被 kube-proxy 当做 client 证书使用，所以 hosts 字段为空；

生成证书和私钥：

$ cd /opt/k8s/work

$ cfssl gencert -ca=/opt/k8s/work/ca.pem \
  -ca-key=/opt/k8s/work/ca-key.pem \
  -config=/opt/k8s/work/ca-config.json \
  -profile=kubernetes  kube-proxy-csr.json | cfssljson -bare kube-proxy
  
$ ls kube-proxy*

二、 创建和分发 kubeconfig 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh

kubectl config set-cluster kubernetes \
  --certificate-authority=/opt/k8s/work/ca.pem \
  --embed-certs=true \
  --server=${KUBE_APISERVER} \
  --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 文件：

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
do
    echo ">>> ${node_name}"
    scp kube-proxy.kubeconfig root@${node_name}:/etc/kubernetes/
done
EOF

三、 创建 kube-proxy 配置文件

从 v1.10 开始，kube-proxy 部分参数可以配置文件中配置。可以使用 --write-config-to 选项生成该配置文件，或者参考 源代码的注释。

创建 kube-proxy config 文件模板：

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh

cat > kube-proxy-config.yaml.template <<EOF
kind: KubeProxyConfiguration
apiVersion: kubeproxy.config.k8s.io/v1alpha1
clientConnection:
  burst: 200
  kubeconfig: "/etc/kubernetes/kube-proxy.kubeconfig"
  qps: 100
bindAddress: ##NODE_IP##
healthzBindAddress: ##NODE_IP##:10256
metricsBindAddress: ##NODE_IP##:10249
enableProfiling: true
clusterCIDR: ${CLUSTER_CIDR}
hostnameOverride: ##NODE_NAME##
mode: "ipvs"
portRange: ""
iptables:
  masqueradeAll: false
ipvs:
  scheduler: rr
  excludeCIDRs: []
EOF

• bindAddress: 监听地址；
• clientConnection.kubeconfig: 连接 apiserver 的 kubeconfig 文件；
• clusterCIDR: kube-proxy 根据 --cluster-cidr 判断集群内部和外部流量，指定 --cluster-cidr 或 --masquerade-all 选项后 kube-proxy 才会对访问 Service IP 的请求做 SNAT；
• hostnameOverride: 参数值必须与 kubelet 的值一致，否则 kube-proxy 启动后会找不到该 Node，从而不会创建任何 ipvs 规则；
• mode: 使用 ipvs 模式；

为各节点创建和分发 kube-proxy 配置文件：

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for (( i=0; i < 3; i++ ))
do  
    echo ">>> ${NODE_NAMES[i]}"
    sed -e "s/##NODE_NAME##/${NODE_NAMES[i]}/" -e "s/##NODE_IP##/${NODE_IPS[i]}/" kube-proxy-config.yaml.template > kube-proxy-config-${NODE_NAMES[i]}.yaml.template
    scp kube-proxy-config-${NODE_NAMES[i]}.yaml.template root@${NODE_NAMES[i]}:/etc/kubernetes/kube-proxy-config.yaml
done
EOF

四、 创建和分发 kube-proxy systemd unit 文件

cd /opt/k8s/work
source /opt/k8s/bin/environment.sh

cat > kube-proxy.service <<EOF
[Unit]
Description=Kubernetes Kube-Proxy Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target

[Service]
WorkingDirectory=${K8S_DIR}/kube-proxy
ExecStart=/opt/k8s/bin/kube-proxy \\
  --config=/etc/kubernetes/kube-proxy-config.yaml \\
  --logtostderr=true \\
  --v=2
Restart=on-failure
RestartSec=5
LimitNOFILE=65536

[Install]
WantedBy=multi-user.target
EOF

分发 kube-proxy systemd unit 文件：

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_name in ${NODE_NAMES[@]}
do
    echo ">>> ${node_name}"
    scp kube-proxy.service root@${node_name}:/etc/systemd/system/
done
EOF

五、 启动 kube-proxy 服务

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "mkdir -p ${K8S_DIR}/kube-proxy"
    ssh root@${node_ip} "modprobe ip_vs_rr"
    ssh root@${node_ip} "systemctl daemon-reload && systemctl enable kube-proxy && systemctl restart kube-proxy"
done
EOF

六、检查启动结果

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "systemctl status kube-proxy|grep Active"
done
EOF

输出结果如下：

$ ./deploy.sh
>>> 192.168.0.71
   Active: active (running) since Mon 2020-04-27 15:49:46 CST; 9s ago
>>> 192.168.0.72
   Active: active (running) since Mon 2020-04-27 15:49:47 CST; 8s ago
>>> 192.168.0.73
   Active: active (running) since Mon 2020-04-27 15:49:48 CST; 8s ago

确保状态为 active (running)，否则如下命令查看日志，确认原因：

journalctl -u kube-proxy

七、 查看监听端口

$ sudo netstat -lnpt|grep kube-prox
tcp        0      0 192.168.0.71:10249      0.0.0.0:*               LISTEN      47812/kube-proxy    
tcp        0      0 192.168.0.71:10256      0.0.0.0:*               LISTEN      47812/kube-proxy    

八、 查看 ipvs 路由规则

cat > deploy.sh << "EOF"
#!/bin/bash
cd /opt/k8s/work
source /opt/k8s/bin/environment.sh
for node_ip in ${NODE_IPS[@]}
do
    echo ">>> ${node_ip}"
    ssh root@${node_ip} "/usr/sbin/ipvsadm -ln"
done
EOF

输出结果如下：

$ ./deploy.sh 
>>> 192.168.0.71
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.254.0.1:443 rr
  -> 192.168.0.71:6443            Masq    1      0          0         
  -> 192.168.0.72:6443            Masq    1      0          0         
  -> 192.168.0.73:6443            Masq    1      0          0         
>>> 192.168.0.72
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.254.0.1:443 rr
  -> 192.168.0.71:6443            Masq    1      0          0         
  -> 192.168.0.72:6443            Masq    1      0          0         
  -> 192.168.0.73:6443            Masq    1      0          0         
>>> 192.168.0.73
IP Virtual Server version 1.2.1 (size=4096)
Prot LocalAddress:Port Scheduler Flags
  -> RemoteAddress:Port           Forward Weight ActiveConn InActConn
TCP  10.254.0.1:443 rr
  -> 192.168.0.71:6443            Masq    1      0          0         
  -> 192.168.0.72:6443            Masq    1      0          0         
  -> 192.168.0.73:6443            Masq    1      0          0     

可见所有通过 https 访问 K8S SVC kubernetes 的请求都转发到 kube-apiserver 节点的 6443 端口。