搭建高可用Kubernetes集群

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本文链接地址: 搭建高可用Kubernetes集群

搭建高可用Kubernetes集群基本遵循一些范例，本文参考他人的文章实验了一次，其中发现了一些问题，经过Debug调试通过，难点在网络问题和kubernates的授权问题。

网络规划

全部节点都在一个低延迟的子网中：

主机名 IP 说明
k8s-lb-01 192.168.0.151
192.168.0.170		 HAProxy + Keepalived (master)
k8s-lb-02 192.168.0.161
192.168.0.170		 HAProxy + Keepalived (backup)
k8s-master-01 192.168.0.152 Master节点1
k8s-master-02 192.168.0.153 Master节点2
k8s-master-03 192.168.0.162 Master节点3
k8s-worker-01 192.168.0.154 Worker节点1

说明：

  • 采用外部HAProxy作集群负载均衡器；
  • 采用2个 HAProxy + Keepalived 来保证负载均衡的高可用，Keepalived VIP为192.168.0.170；即整个集群的IP地址。
  • 采用每个Master节点上伴随部署Etcd的方式(Slacked Etcd typology 堆叠Etcd拓扑），而Etcd高可用最少需要3个节点（奇数），因此Master节点至少为3个。
  • 1个worker节点，只是测试集群，所以1个就OK了。
  • 服务器规格都为CentOS7 x86_64。
  • 全部机器都在192.168.0.0/24网段，且相互连通。
  • Docker 19.03.11
  • Kubernetes v1.19.3
  • Calico网络组件
  • HAProxy负载均衡
  • 集群Control-Plane Endpoint：192.168.0.170:6443
  • 集群API Server(s)：
    • 192.168.0.152:6443
    • 192.168.0.153:6443
    • 192.168.0.162:6443
    部署一个基础镜像供拷贝使用
    拉取k8s-deploy项目
    # 安装Git
yum install git -y
 
# 拉取k8s-deploy项目
mkdir -p ~/k8s
cd ~/k8s
git clone https://github.com/cookcodeblog/k8s-deploy.git
 
# 增加脚本的可执行文件权限
cd k8s-deploy/kubeadm_v1.19.3
find . -name '*.sh' -exec chmod u+x {} \;
    安装Kubernetes
    # 安装前检查和配置
bash 01_pre_check_and_configure.sh
 
# 安装Docker
bash 02_install_docker.sh
 
# 安装kubeadm, kubectl, kubelet
bash 03_install_kubernetes.sh
 
# 拉取Kubernetes集群要用到的镜像
bash 04_pull_kubernetes_images_from_aliyun.sh
 
# 拉取Calico网络组件的镜像
bash 04_pull_calico_images.sh
 
iptables -P FORWARD ACCEPT
    克隆服务器作为基准镜像

    关机，然后拷贝这个镜像，生成k8s-master-02，k8s-master-03，k8s-worker-01，k8s-lb-01，k8s-lb-02。然后修改所有机器的IP地址为对应的静态地址。
    vi /etc/sysconfig/network-scripts/ifcfg-ens33

    bootproto=static
onboot=yes
IPADDR=192.168.0.153
NETMASK=255.255.255.0
GATEWAY=192.168.0.1
DNS1=192.168.0.1
DNS2=8.8.8.8

    #重启网络服务
    systemctl restart network

    部署负载均衡服务器（k8s-lb-01，k8s-lb-02）
    安装和配置HAProxy

    安装HAProxy：

    yum install haproxy -y

    编辑/etc/haproxy/haproxy.cfg，删掉对应默认的代理设置，添加负载均衡反向代理到Kubernetes集群Master节点的设置：

    #---------------------------------------------------------------------
# apiserver frontend which proxys to the masters
#---------------------------------------------------------------------
frontend apiserver
    bind *:6443
    mode tcp
    option tcplog
    default_backend apiserver
 
#---------------------------------------------------------------------
# round robin balancing for apiserver
#---------------------------------------------------------------------
backend apiserver
    option httpchk GET /healthz
    http-check expect status 200
    mode tcp
    option ssl-hello-chk
    balance     roundrobin
        server k8s-master-01 192.168.0.152:6443 check
        server k8s-master-02 192.168.0.153:6443 check
        server k8s-master-03 192.168.0.162:6443 check

    开启HAProxy服务：

    systemctl daemon-reload
systemctl enable haproxy
systemctl start haproxy
systemctl status haproxy -l
    安装和配置Keepalived

    安装Keepalived：

    yum install keepalived -y

    配置Linux系统内核参数：

    sudo cat <  /etc/sysctl.d/keepalived.conf
net.ipv4.ip_forward = 1
net.ipv4.ip_nonlocal_bind = 1
EOF
 
#ip_forward 允许IP转发
#ip_nonlocal_bind允许绑定浮动IP，即VIP
sudo sysctl --system

    在/etc/keepalived下新建check_apiserver.sh用来Keepalived作健康检查：

    #!/bin/sh
 
 
APISERVER_VIP=$1
APISERVER_DEST_PORT=$2
 
errorExit() {
    echo "*** $*" 1>&2
    exit 1
}
 
curl --silent --max-time 2 --insecure https://localhost:${APISERVER_DEST_PORT}/ -o /dev/null || errorExit "Error GET https://localhost:${APISERVER_DEST_PORT}/"
if ip addr | grep -q ${APISERVER_VIP}; then
    curl --silent --max-time 2 --insecure https://${APISERVER_VIP}:${APISERVER_DEST_PORT}/ -o /dev/null || errorExit "Error GET https://${APISERVER_VIP}:${APISERVER_DEST_PORT}/"
fi
    chmod +x /etc/keepalived/check_apiserver.sh

    在Keepalived master节点上的/etc/keepalived/keepalived.conf中的配置为：

    ! /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
    router_id LVS_DEVEL
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh 192.168.0.170 6443"
  interval 3
  weight -2
  fall 10
  rise 2
}
 
vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 101
    authentication {
        auth_type PASS
        auth_pass Keep@lived
    }
    virtual_ipaddress {
        192.168.0.170
    }
    track_script {
        check_apiserver
    }
}

    在Keepalived backup节点上的/etc/keepalived/keepalived.conf中的配置为：

    ! /etc/keepalived/keepalived.conf
! Configuration File for keepalived
global_defs {
    router_id LVS_DEVEL
}
vrrp_script check_apiserver {
  script "/etc/keepalived/check_apiserver.sh 192.168.0.170 6443"
  interval 3
  weight -2
  fall 10
  rise 2
}
 
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 51
    priority 100
    authentication {
        auth_type PASS
        auth_pass Keep@lived
    }
    virtual_ipaddress {
        192.168.0.170
    }
    track_script {
        check_apiserver
    }
}

    让HAProxy使用Keepalived VIP，修改HAProxy的配置文件，绑定frontend IP为Keepalived VIP：

    frontend apiserver
    bind 192.168.0.170:6443

    运行Keepalived：

    systemctl daemon-reload
systemctl enable keepalived
systemctl start keepalived
systemctl status keepalived -l
 
systemctl daemon-reload
systemctl restart haproxy
    初始化集群（在k8s-master-02上）
    kubeadm init
    cd ~/k8s
cd k8s-deploy/kubeadm_v1.19.3
 
# 05_kubeadm_init.sh 
bash 05_kubeadm_init.sh 192.168.0.170:6443

    05_kubeadm_init.sh中的service-cidr和pod-network-cidr需要修改，且不能和当前主机环境的CIDR一样。pod-network-cidr后面安装网络插件calico需要使用。

    kubeadm init \
  --kubernetes-version=v1.19.3 \
  --control-plane-endpoint=${CONTROL_PLANE_ENDPOINT} \
  --service-cidr=10.96.0.0/16 \
  --pod-network-cidr=10.244.0.0/16 \
  --image-repository=${IMAGE_REPOSITORY} \
  --upload-certs

    记录上面脚本输出中的kubeadm join 内容，后面用。

    安装Calico网络组件

    需要先修改calico/calico-ens33.xml中的内容：

                - name: CALICO_IPV4POOL_CIDR
              value: "10.244.0.0/16"
 
            - name: KUBERNETES_SERVICE_HOST
              value: "192.168.0.170"
            - name: KUBERNETES_SERVICE_PORT
              value: "6443"
            - name: KUBERNETES_SERVICE_PORT_HTTPS
              value: "6443"
    # support eth* and ens* networkd interfaces
bash 06_install_calico.sh ens33
    部署Worker节点

    运行kubeadm init中打印的日志中关于加入“worker node”的命令。

    示例：

    kubeadm join 192.168.0.170:6443 --token r7w69v.3e1nweyk81h5zj6y \
    --discovery-token-ca-cert-hash sha256:1234a2317d27f0a4c6bcf5f284416a2fb3e8f3bd61aa88bc279a4f6ef18e09a1

    让Worker节点上的kubectl命令生效：

    bash enable_kubectl_worker.sh
    部署其他Master节点

    运行kubeadm init中打印的日志中关于加入“control-plane node”的命令。

    示例：

    kubeadm join 192.168.0.170:6443 --token r7w69v.3e1nweyk81h5zj6y \
    --discovery-token-ca-cert-hash sha256:1234a2317d27f0a4c6bcf5f284416a2fb3e8f3bd61aa88bc279a4f6ef18e09a1 \
    --control-plane --certificate-key 0e48107fbcd11cda60a5c2b76ae488b4ebf57223a4001acac799996740a6044e

    如果忘记了kubeadm join命令的内容，可运行kubeadm token create –print-join-command重新获取，并可运行kubeadm init phase upload-certs –upload-certs获取新的certificate-key。

    让Master节点上的kubectl命令生效：

    bash enable_kubectl_master.sh
    查看集群部署情况
    # Display cluster info
kubectl cluster-info
 
# Nodes
kubectl get nodes
 
# Display pds
kubectl get pods --all-namespaces -o wide
 
# Check pods status incase any pods are not in running status
kubectl get pods --all-namespaces | grep -v Running
    (可选）安装Dashboard
    kubectl apply -f https://raw.githubusercontent.com/kubernetes/dashboard/v2.2.0/aio/deploy/recommended.yaml

    创建文件dashboard-adminuser.yaml应用来添加管理员

    ---
apiVersion: v1
kind: ServiceAccount
metadata:
  name: admin-user
  namespace: kubernetes-dashboard
 
---
apiVersion: rbac.authorization.k8s.io/v1
kind: ClusterRoleBinding
metadata:
  name: admin-user
roleRef:
  apiGroup: rbac.authorization.k8s.io
  kind: ClusterRole
  name: cluster-admin
subjects:
- kind: ServiceAccount
  name: admin-user
  namespace: kubernetes-dashboard

    然后执行下面命令后，拷贝输出的token来登录Dashboard：

    kubectl apply -f dashboard-adminuser.yaml
 
kubectl -n kubernetes-dashboard describe secret $(kubectl -n kubernetes-dashboard get secret | grep admin-user | awk '{print $1}')

    使用如下命令来把Dashboard暴露出docker：

    kubectl -n kubernetes-dashboard  port-forward kubernetes-dashboard-7cb9fd9999-gtjn7 --address 0.0.0.0 8443

    现在可访问：https://k8s-master-01:8443

    大部分内容参考在CentOS7上用kubeadm HAProxy Keepalived 安装多Master节点的高可用Kubernetes集群

本作品采用知识共享署名 4.0 国际许可协议进行许可。

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