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使用 kubeadm 搭建 Kubernetes 高可用集群

基础设施
394 字
DockerKubernetes
本文记录了如何使用 kubeadm 工具搭建高可用 Kubernetes 集群，主要通过 keepalived+haproxy 组合实现 master 节点的高可用架构，整个部署基于 CentOS 7 系统，Kubernetes 版本为 1.16.3。

kubeadm 是 Kubernetes 官方推出的集群部署工具，通过简单的命令即可快速搭建生产级别的 Kubernetes 集群。

1. 环境要求

  • 操作系统: CentOS 7.x-86_x64
  • 硬件配置: 2GB+ RAM，2+ CPU，30GB+ 磁盘
  • 网络要求: 能够访问外网拉取镜像
  • 其他要求: 禁用 swap 分区

2. 集群规划

角色IP 地址备注
master1192.168.44.155主控制节点
master2192.168.44.156备用控制节点
node1192.168.44.157工作节点
VIP192.168.44.158虚拟 IP

3. 基础环境配置

在所有节点执行以下操作：

bash 
# 关闭防火墙和 SELinux
systemctl stop firewalld && systemctl disable firewalld
sed -i 's/enforcing/disabled/' /etc/selinux/config && setenforce 0

# 关闭 swap
swapoff -a && sed -ri 's/.*swap.*/#&/' /etc/fstab

# 配置主机名和 hosts 文件
hostnamectl set-hostname <对应主机名>
cat >> /etc/hosts << EOF
192.168.44.158    master.k8s.io
192.168.44.155    master01.k8s.io
192.168.44.156    master02.k8s.io
192.168.44.157    node01.k8s.io
EOF

# 配置内核参数
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

# 时间同步
yum install ntpdate -y && ntpdate time.windows.com
# 关闭防火墙和 SELinux
systemctl stop firewalld && systemctl disable firewalld
sed -i 's/enforcing/disabled/' /etc/selinux/config && setenforce 0

# 关闭 swap
swapoff -a && sed -ri 's/.*swap.*/#&/' /etc/fstab

# 配置主机名和 hosts 文件
hostnamectl set-hostname <对应主机名>
cat >> /etc/hosts << EOF
192.168.44.158    master.k8s.io
192.168.44.155    master01.k8s.io
192.168.44.156    master02.k8s.io
192.168.44.157    node01.k8s.io
EOF

# 配置内核参数
cat > /etc/sysctl.d/k8s.conf << EOF
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

# 时间同步
yum install ntpdate -y && ntpdate time.windows.com

4. 配置高可用负载均衡

4.1 安装 keepalived

在两台 master 节点安装 keepalived：

bash 
yum install -y keepalived
yum install -y keepalived

master1 配置 (/etc/keepalived/keepalived.conf)：

bash 
cat > /etc/keepalived/keepalived.conf <<EOF 
global_defs {
   router_id k8s
}

vrrp_script check_haproxy {
    script "killall -0 haproxy"
    interval 3
    weight -2
    fall 10
    rise 2
}

vrrp_instance VI_1 {
    state MASTER 
    interface ens33 
    virtual_router_id 51
    priority 250
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass ceb1b3ec013d66163d6ab
    }
    virtual_ipaddress {
        192.168.44.158
    }
    track_script {
        check_haproxy
    }
}
EOF
cat > /etc/keepalived/keepalived.conf <<EOF 
global_defs {
   router_id k8s
}

vrrp_script check_haproxy {
    script "killall -0 haproxy"
    interval 3
    weight -2
    fall 10
    rise 2
}

vrrp_instance VI_1 {
    state MASTER 
    interface ens33 
    virtual_router_id 51
    priority 250
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass ceb1b3ec013d66163d6ab
    }
    virtual_ipaddress {
        192.168.44.158
    }
    track_script {
        check_haproxy
    }
}
EOF

master2 配置：同 master1，但修改 state BACKUP 和 priority 200。

启动 keepalived：

bash 
systemctl enable keepalived && systemctl start keepalived
systemctl enable keepalived && systemctl start keepalived

4.2 安装 HAProxy

在两台 master 节点安装并配置 HAProxy：

bash 
yum install -y haproxy

cat > /etc/haproxy/haproxy.cfg << EOF
global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

frontend kubernetes-apiserver
    mode                 tcp
    bind                 *:16443
    option               tcplog
    default_backend      kubernetes-apiserver

backend kubernetes-apiserver
    mode        tcp
    balance     roundrobin
    server      master01.k8s.io   192.168.44.155:6443 check
    server      master02.k8s.io   192.168.44.156:6443 check

listen stats
    bind                 *:1080
    stats auth           admin:awesomePassword
    stats refresh        5s
    stats realm          HAProxy\ Statistics
    stats uri            /admin?stats
EOF

systemctl enable haproxy && systemctl start haproxy
yum install -y haproxy

cat > /etc/haproxy/haproxy.cfg << EOF
global
    log         127.0.0.1 local2
    chroot      /var/lib/haproxy
    pidfile     /var/run/haproxy.pid
    maxconn     4000
    user        haproxy
    group       haproxy
    daemon

defaults
    mode                    http
    log                     global
    option                  httplog
    option                  dontlognull
    option http-server-close
    option forwardfor       except 127.0.0.0/8
    option                  redispatch
    retries                 3
    timeout http-request    10s
    timeout queue           1m
    timeout connect         10s
    timeout client          1m
    timeout server          1m
    timeout http-keep-alive 10s
    timeout check           10s
    maxconn                 3000

frontend kubernetes-apiserver
    mode                 tcp
    bind                 *:16443
    option               tcplog
    default_backend      kubernetes-apiserver

backend kubernetes-apiserver
    mode        tcp
    balance     roundrobin
    server      master01.k8s.io   192.168.44.155:6443 check
    server      master02.k8s.io   192.168.44.156:6443 check

listen stats
    bind                 *:1080
    stats auth           admin:awesomePassword
    stats refresh        5s
    stats realm          HAProxy\ Statistics
    stats uri            /admin?stats
EOF

systemctl enable haproxy && systemctl start haproxy

5. 安装容器运行时和 Kubernetes 组件

在所有节点执行：

5.1 安装 Docker

bash 
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum install -y docker-ce-18.06.1.ce-3.el7

cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF

systemctl enable docker && systemctl start docker
wget https://mirrors.aliyun.com/docker-ce/linux/centos/docker-ce.repo -O /etc/yum.repos.d/docker-ce.repo
yum install -y docker-ce-18.06.1.ce-3.el7

cat > /etc/docker/daemon.json << EOF
{
  "registry-mirrors": ["https://b9pmyelo.mirror.aliyuncs.com"]
}
EOF

systemctl enable docker && systemctl start docker

5.2 安装 kubeadm、kubelet、kubectl

bash 
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

yum install -y kubelet-1.16.3 kubeadm-1.16.3 kubectl-1.16.3
systemctl enable kubelet
cat > /etc/yum.repos.d/kubernetes.repo << EOF
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64
enabled=1
gpgcheck=0
repo_gpgcheck=0
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF

yum install -y kubelet-1.16.3 kubeadm-1.16.3 kubectl-1.16.3
systemctl enable kubelet

6. 初始化 Kubernetes 集群

6.1 创建集群配置文件

在 master1 节点创建 kubeadm 配置文件：

bash 
mkdir -p /usr/local/kubernetes/manifests && cd /usr/local/kubernetes/manifests

cat > kubeadm-config.yaml << EOF
apiServer:
  certSANs:
    - master1
    - master2
    - master.k8s.io
    - 192.168.44.158
    - 192.168.44.155
    - 192.168.44.156
    - 127.0.0.1
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta1
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "master.k8s.io:16443"
controllerManager: {}
dns: 
  type: CoreDNS
etcd:
  local:  
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.16.3
networking: 
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.1.0.0/16
scheduler: {}
EOF
mkdir -p /usr/local/kubernetes/manifests && cd /usr/local/kubernetes/manifests

cat > kubeadm-config.yaml << EOF
apiServer:
  certSANs:
    - master1
    - master2
    - master.k8s.io
    - 192.168.44.158
    - 192.168.44.155
    - 192.168.44.156
    - 127.0.0.1
  extraArgs:
    authorization-mode: Node,RBAC
  timeoutForControlPlane: 4m0s
apiVersion: kubeadm.k8s.io/v1beta1
certificatesDir: /etc/kubernetes/pki
clusterName: kubernetes
controlPlaneEndpoint: "master.k8s.io:16443"
controllerManager: {}
dns: 
  type: CoreDNS
etcd:
  local:  
    dataDir: /var/lib/etcd
imageRepository: registry.aliyuncs.com/google_containers
kind: ClusterConfiguration
kubernetesVersion: v1.16.3
networking: 
  dnsDomain: cluster.local
  podSubnet: 10.244.0.0/16
  serviceSubnet: 10.1.0.0/16
scheduler: {}
EOF

6.2 初始化第一个 master 节点

bash 
kubeadm init --config kubeadm-config.yaml

# 配置 kubectl
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config
kubeadm init --config kubeadm-config.yaml

# 配置 kubectl
mkdir -p $HOME/.kube
cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
chown $(id -u):$(id -g) $HOME/.kube/config

记录输出的 join 命令，后续加入节点时使用。

6.3 安装网络插件

bash 
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml
wget https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
kubectl apply -f kube-flannel.yml

7. 添加第二个 master 节点

7.1 复制证书文件

从 master1 复制必要文件到 master2：

bash 
ssh root@192.168.44.156 mkdir -p /etc/kubernetes/pki/etcd
scp /etc/kubernetes/admin.conf root@192.168.44.156:/etc/kubernetes
scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@192.168.44.156:/etc/kubernetes/pki
scp /etc/kubernetes/pki/etcd/ca.* root@192.168.44.156:/etc/kubernetes/pki/etcd
ssh root@192.168.44.156 mkdir -p /etc/kubernetes/pki/etcd
scp /etc/kubernetes/admin.conf root@192.168.44.156:/etc/kubernetes
scp /etc/kubernetes/pki/{ca.*,sa.*,front-proxy-ca.*} root@192.168.44.156:/etc/kubernetes/pki
scp /etc/kubernetes/pki/etcd/ca.* root@192.168.44.156:/etc/kubernetes/pki/etcd

7.2 加入集群

在 master2 节点执行 join 命令（添加 --control-plane 参数）：

bash 
kubeadm join master.k8s.io:16443 --token <token> \
    --discovery-token-ca-cert-hash sha256:<hash> \
    --control-plane
kubeadm join master.k8s.io:16443 --token <token> \
    --discovery-token-ca-cert-hash sha256:<hash> \
    --control-plane

8. 添加工作节点

在 node1 节点执行 join 命令（不需要 --control-plane 参数）：

bash 
kubeadm join master.k8s.io:16443 --token <token> \
    --discovery-token-ca-cert-hash sha256:<hash>
kubeadm join master.k8s.io:16443 --token <token> \
    --discovery-token-ca-cert-hash sha256:<hash>

9. 验证集群

创建测试应用验证集群功能：

bash 
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pods,svc
kubectl create deployment nginx --image=nginx
kubectl expose deployment nginx --port=80 --type=NodePort
kubectl get pods,svc

通过 http://<任意节点 IP>:<NodePort> 访问 nginx 服务。

10. 常用维护命令

bash 
# 查看集群状态
kubectl get nodes
kubectl get cs

# 查看所有 Pod
kubectl get pods --all-namespaces

# 重新生成 join token
kubeadm token create --print-join-command

# 查看集群信息
kubectl cluster-info
# 查看集群状态
kubectl get nodes
kubectl get cs

# 查看所有 Pod
kubectl get pods --all-namespaces

# 重新生成 join token
kubeadm token create --print-join-command

# 查看集群信息
kubectl cluster-info

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