kubernetes部署 kube-apiserver服务

kubernetes部署 kube-apiserver 组件

本文档讲解使用 keepalived 和 haproxy 部署一个 3 节点高可用 master 集群的步骤。

kube-apiserver 集群各节点的名称和 IP 如下：

kube-node0：192.168.111.10
kube-node1：192.168.111.11
kube-node2：192.168.111.12

创建 kubernetes 证书和私钥
其中会用到上面的三个主机IP，一个vip（192.168.111.9），这些都是kube-apiserver的对外提供服务的IP，还有就是kubernetes本身会创建一个service，它的IP是我们在启动kube-apiserver是定义的--service-cluster-ip-range 参数指定的IP地址段（10.254.0.0/24,）的第一个IP地址，后续可以通过kubectl get svc kubernetes命令获取。

cat > kubernetes-csr.json <<EOF
{
  "CN": "kubernetes",
  "hosts": [
    "127.0.0.1",
    "192.168.111.9",
    "192.168.111.10",
    "192.168.111.11",
    "192.168.111.12",
    "10.254.0.1",
    "kubernetes",
    "kubernetes.default",
    "kubernetes.default.svc",
    "kubernetes.default.svc.cluster",
    "kubernetes.default.svc.cluster.local"
  ],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "ChongQing",
      "L": "ChongQing",
      "O": "k8s",
      "OU": "yunwei"
    }
  ]
}
EOF

生成认证文件：

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

将生成的证书和私钥文件拷贝到其他kube-apiserver节点
# scp /etc/kubernetes/ca/kubernetes* 192.168.111.11:/etc/kubernetes/ca/
# scp /etc/kubernetes/ca/kubernetes* 192.168.111.12:/etc/kubernetes/ca/

生成token认证文件

#生成随机token
# head -c 16 /dev/urandom | od -An -t x | tr -d ' '
8afdf3c4eb7c74018452423c29433609

#按照固定格式写入token.csv，注意替换token内容
# echo "8afdf3c4eb7c74018452423c29433609,kubelet-bootstrap,10001,\"system:kubelet-bootstrap\"" > /etc/kubernetes/ca/token.csv
kube-apiserver的配置文件，三台一样（配置文件中将127.0.0.1的非https的api开放，在kube-scheduler服务和kube-controller-manager服务就可以不用认证授权了。）：

cat > /lib/systemd/system/kube-apiserver.service <<EOF
[Unit]
Description=Kubernetes API Server
Documentation=https://github.com/GoogleCloudPlatform/kubernetes
After=network.target
[Service]
ExecStart=/usr/local/bin/kube-apiserver \
  --admission-control=NamespaceLifecycle,LimitRanger,ServiceAccount,DefaultStorageClass,ResourceQuota,NodeRestriction \
  --insecure-bind-address=127.0.0.1 \
  --kubelet-https=true \
  --bind-address=192.168.111.12 \
  --authorization-mode=Node,RBAC \
  --runtime-config=api/all \
  --enable-bootstrap-token-auth \
  --token-auth-file=/etc/kubernetes/ca/token.csv \
  --tls-cert-file=/etc/kubernetes/ca/kubernetes.pem \
  --tls-private-key-file=/etc/kubernetes/ca/kubernetes-key.pem \
  --client-ca-file=/etc/kubernetes/ca/ca.pem \
  --service-account-key-file=/etc/kubernetes/ca/ca-key.pem \
  --etcd-cafile=/etc/kubernetes/ca/ca.pem \
  --etcd-certfile=/etc/kubernetes/ca/kubernetes.pem \
  --etcd-keyfile=/etc/kubernetes/ca/kubernetes-key.pem \
  --service-cluster-ip-range=10.254.0.0/16 \
  --etcd-servers=https://192.168.111.10:2379,https://192.168.111.11:2379,https://192.168.111.12:2379 \
  --enable-swagger-ui=true \
  --allow-privileged=true \
  --audit-log-maxage=30 \
  --audit-log-maxbackup=3 \
  --audit-log-maxsize=100 \
  --audit-log-path=/var/lib/audit.log \
  --v=2
Restart=on-failure
RestartSec=5
Type=notify
LimitNOFILE=65536
[Install]
WantedBy=multi-user.target
EOF

systemctl daemon-reload && for SERVICES in kube-apiserver;do systemctl enable $SERVICES; systemctl restart $SERVICES; systemctl status $SERVICES; done

打印 kube-apiserver 写入 etcd 的数据

ETCDCTL_API=3 etcdctl \
--endpoints=https://192.168.111.10:2379,https://192.168.111.11:2379,https://192.168.111.12:2379 \
--cacert=/etc/kubernetes/ca/ca.pem \
--cert=/etc/kubernetes/ca/etcd.pem \
--key=/etc/kubernetes/ca/etcd-key.pem \
get /registry/ --prefix --keys-only

部署 kubectl 命令行工具

cat > admin-csr.json <<EOF
{
  "CN": "admin",
  "hosts": [],
  "key": {
    "algo": "rsa",
    "size": 2048
  },
  "names": [
    {
      "C": "CN",
      "ST": "ChongQing",
      "L": "ChongQing",
      "O": "system:masters",
      "OU": "yunwei"
    }
  ]
}
EOF

生成认证文件：

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

生成kubectl的config文件（可以三台都执行一遍，也可以一台执行后复制过去）：

kubectl config set-cluster kubernetes \
  --certificate-authority=/etc/kubernetes/ca/ca.pem \
  --embed-certs=true \
  --server=https://192.168.111.9:8443
kubectl config set-credentials admin \
  --client-certificate=/etc/kubernetes/ca/admin.pem \
  --client-key=/etc/kubernetes/ca/admin-key.pem \
  --embed-certs=true
kubectl config set-context kubernetes \
  --cluster=kubernetes \
  --user=admin
kubectl config use-context kubernetes 

mkdir -p ~/.kube

scp ~/.kube/config 192.168.111.11:~/.kube/config
scp ~/.kube/config 192.168.111.12:~/.kube/config

检查集群信息(任意一台)

# kubectl cluster-info
Kubernetes master is running at https://192.168.111.9:8443

To further debug and diagnose cluster problems, use 'kubectl cluster-info dump'.
# kubectl get all --all-namespaces
NAMESPACE   NAME                 TYPE        CLUSTER-IP   EXTERNAL-IP   PORT(S)   AGE
default     service/kubernetes   ClusterIP   10.254.0.1   <none>        443/TCP   34d
# kubectl get componentstatuses
NAME                 STATUS      MESSAGE                                                                                     ERROR
scheduler            Unhealthy   Get http://127.0.0.1:10251/healthz: dial tcp 127.0.0.1:10251: connect: connection refused
controller-manager   Unhealthy   Get http://127.0.0.1:10252/healthz: dial tcp 127.0.0.1:10252: connect: connection refused
etcd-2               Healthy     {"health": "true"}
etcd-0               Healthy     {"health": "true"}
etcd-1               Healthy     {"health": "true"}                                                           

检查 kube-apiserver 监听的端口
6443: 接收 https 请求的安全端口，对所有请求做认证和授权

# ss -netstat -lnpt|grep kube
LISTEN     0      128    192.168.111.12:6443                     *:*                   users:(("kube-apiserver",pid=878,fd=3)) timer:(keepalive,031ms,0) ino:23491 sk:ffff880078d34d80 <->
LISTEN     0      128    127.0.0.1:8080                     *:*                   users:(("kube-apiserver",pid=4168,fd=68)) ino:35479 sk:ffff88002391ec80 <->