Kubernetes 运维 - 高可用集群方案

• 一、概述
• 二、搭建负载均衡高可用
• • 1.1 基础环境
  • • 1.1.1 配置Hosts文件
    • 1.1.2 配置互信(可选)
    • 1.1.3 系统优化
    • • ① 关闭防火墙&selinux&swap分区&iptables
      • ② 优化内核参数
      • ③ 配置时间同步
      • ④ kube-proxy开启ipvs的前置
    • 1.1.4 安装Docker
    • 1.1.5 安装Kubernetes
    • • ① 配置阿里源
      • ② 安装kubelet
  • 1.2 安装Haproxy
  • • 1.2.1 通过yum安装haproxy
    • 1.2.2 配置文件
    • 1.2.3 启动并设置开机自启
  • 1.3 部署Keepalived
  • • 1.3.1 通过yum安装keepalived
    • 1.3.2 配置文件
    • • ① Master-01
      • ② Master-02
      • ③ Master-03
    • 1.3.3 启动并设置开机自启
  • 1.4 初始化集群
  • • 1.4.1 创建kubeadm-config文件
    • 1.4.2 创建目录
    • 1.4.3 安装calico网络
    • 1.4.4 上传证书
    • 1.4.5 将其他Master加入到集群
    • 1.4.6 查看集群状态
    • • ① 检查etcd集群健康状态
      • ② 检查组件
    • 1.4.7 设置污点
  • 1.5 测试
  • • 1.5.1 打开haproxy状态页面

---

一、概述

Keepalived 用于提供 kube-apiserver 对外服务的 VIP 地址
Haproxy 用于监听 VIP 地址，后端连接所有 kube-apiserver 实例，提供监控检查和负载均衡功能

keepalived在运行过程中对本机的haproxy进行状态进行周期性检查，如果检测到haproxy进程异常，则触发重新选主的过程，VIP也将漂移到新选出来的节点上，从而实现VIP的高可用

二、搭建负载均衡高可用

节点名	IP地址	使用端口	K8S版本
master-01	192.168.0.10	HA(8443)	1.18.2
master-02	192.168.0.20	HA(8443)	1.18.2
master-03	192.168.0.30	HA(8443)	1.18.2

1.1 基础环境

1.1.1 配置Hosts文件

192.168.0.10 master-01
192.168.0.20 master-02
192.168.0.30 master-03

1.1.2 配置互信(可选)

ssh-keygen -t rsa
ssh-copy-id 节点名

1.1.3 系统优化

① 关闭防火墙&selinux&swap分区&iptables

systemctl stop firewalld && systemctl disable firewalld

swapoff -a && sed -i '/ swap / s/^\(.*\)$/#\1/g' /etc/fstab

setenforce 0 && sed -i 's/^SELINUX=.*/SELINUX=disabled/' /etc/selinux/config

yum -y install iptables-services
systemctl start iptables && systemctl enable iptables
iptables -F && service iptables save

② 优化内核参数

cat <<EOF >  /etc/sysctl.d/k8s.conf
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
EOF
sysctl --system

cat <<EOF > /etc/sysctl.conf
fs.aio-max-nr=1065535
kernel.pid_max=600000
net.ipv4.tcp_max_syn_backlog=30000
net.core.somaxconn=65535
net.ipv4.tcp_tw_reuse=1
net.ipv4.tcp_timestamps=1
net.ipv4.ip_local_reserved_ports=30000-32767
net.ipv4.ip_local_port_range=30000 65000
net.core.netdev_max_backlog=300000
net.ipv4.tcp_rmem=4096 87380 134217728
net.ipv4.tcp_wmem=4096 87380 134217728
net.ipv4.tcp_sack=0
net.ipv4.tcp_fin_timeout=20
fs.inotify.max_user_watches=102400
EOF
sysctl -p

modprobe br_netfilter
sysctl -p /etc/sysctl.d/k8s.conf

③ 配置时间同步

yum install -y chrony
systemctl enable --now chronyd

timedatectl set-timezone Asia/Shanghai
timedatectl set-local-rtc 0

④ kube-proxy开启ipvs的前置

yum install ipset ipvsadm -y

cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF

chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4

1.1.4 安装Docker

Docker 运维 - 从零开始学习

本章中部署的K8S版本为1.18.2，需要安装Docker版本为18.09.1

1.1.5 安装Kubernetes

① 配置阿里源

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

② 安装kubelet

yum install -y kubelet-1.18.2 kubeadm-1.18.2 kubectl-1.18.2
rpm -qa | grep kube
systemctl enable kubelet

1.2 安装Haproxy

1.2.1 通过yum安装haproxy

yum -y install haproxy

1.2.2 配置文件

vim /etc/haproxy/haproxy.cfg

global
    log /dev/log    local0
    log /dev/log    local1 notice
    chroot /var/lib/haproxy
    stats socket /var/run/haproxy-admin.sock mode 660 level admin
    stats timeout 30s
    user haproxy
    group haproxy
    daemon
    nbproc 1

defaults
    log     global
    timeout connect 5000
    timeout client  10m
    timeout server  10m

listen  admin_stats
    bind 0.0.0.0:10080
    mode http
    log 127.0.0.1 local0 err
    stats refresh 30s
    stats uri /status
    stats realm welcome login\ Haproxy
    stats auth admin:123456
    stats hide-version
    stats admin if TRUE

listen kube-master
    bind 0.0.0.0:8443
    mode tcp
    option tcplog
    balance source
    server 192.168.0.10 192.168.0.10:6443 check inter 2000 fall 2 rise 2 weight 1
    server 192.168.0.20 192.168.0.20:6443 check inter 2000 fall 2 rise 2 weight 1
    server 192.168.0.30 192.168.0.30:6443 check inter 2000 fall 2 rise 2 weight 1

1.2.3 启动并设置开机自启

systemctl enable haproxy && systemctl restart haproxy
netstat -lnpt|grep haproxy

1.3 部署Keepalived

1.3.1 通过yum安装keepalived

yum -y install keepalived

1.3.2 配置文件

vim /etc/keepalived/keepalived.conf

① Master-01

global_defs {
   router_id master-01
}
vrrp_script check-haproxy {
    #检查所在节点的 haproxy 进程是否正常。如果异常则将权重减少3
    script "killall -0 haproxy"
    interval 5
    weight -3
}
vrrp_instance VI_1 {
    state MASTER
    #VIP所在接口
    interface ens33
    dont_track_primary
    #VIP末段
    virtual_router_id 100
    priority 100
    advert_int 3
    track_script {
        check-haproxy
    }
    virtual_ipaddress {
        192.168.0.100/24
    }
}

② Master-02

global_defs {
   router_id master-01
}
vrrp_script check-haproxy {
    script "killall -0 haproxy"
    interval 5
    weight -3
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 100
    dont_track_primary
    priority 99
    advert_int 3
    track_script {
        check-haproxy
    }
    virtual_ipaddress {
        192.168.0.100/24
    }
}

③ Master-03

global_defs {
   router_id master-01
}
vrrp_script check-haproxy {
    script "killall -0 haproxy"
    interval 5
    weight -3
}
vrrp_instance VI_1 {
    state BACKUP
    interface ens33
    virtual_router_id 100
    dont_track_primary
    priority 98
    advert_int 3
    track_script {
        check-haproxy
    }
    virtual_ipaddress {
        192.168.0.100/24
    }
}

1.3.3 启动并设置开机自启

systemctl start keepalived && systemctl enable keepalived

ip a

1.4 初始化集群

1.4.1 创建kubeadm-config文件

mkdir k8s
cd k8s

cat > kubeadm-config.yaml << EOF
apiVersion: kubeadm.k8s.io/v1beta2
kind: ClusterConfiguration
kubernetesVersion: v1.18.2
apiServer:
  certSANs:
  - 192.168.0.10  #Master-01
  - 192.168.0.20  #Master-02
  - 192.168.0.30  #Master-03
  - 192.168.0.100 #VIP
controlPlaneEndpoint: "192.168.0.100:6443"
imageRepository: registry.aliyuncs.com/google_containers

networking:
  podSubnet: "10.244.0.0/16"
  serviceSubnet: 10.1.0.0/16

---
apiVersion: kubeproxy.config.k8s.io/v1alpha1
kind: KubeProxyConfiguration
featureGates:
  SupportIPVSProxyMode: true
mode: ipvs
EOF


kubeadm init --config=kubeadm-config.yaml

1.4.2 创建目录

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

1.4.3 安装calico网络

kubectl apply -f https://docs.projectcalico.org/manifests/calico.yaml

1.4.4 上传证书

先在集群的另外两个Master上创建目录

mkdir -p /etc/kubernetes/pki/etcd

在Master-01创建拷贝脚本

echo 'USER=root
CONTROL_PLANE_IPS="192.168.0.20 192.168.0.30"
for host in ${CONTROL_PLANE_IPS}; do
    scp /etc/kubernetes/pki/ca.crt "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/ca.key "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/sa.key "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/sa.pub "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/front-proxy-ca.crt "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/front-proxy-ca.key "${USER}"@$host:/etc/kubernetes/pki/
    scp /etc/kubernetes/pki/etcd/ca.crt "${USER}"@$host:/etc/kubernetes/pki/etcd/
    scp /etc/kubernetes/pki/etcd/ca.key "${USER}"@$host:/etc/kubernetes/pki/etcd/
done' > ca.sh

bash ca.sh

1.4.5 将其他Master加入到集群

kubeadm join 192.168.0.100:6443 --token edb58d.82zbfmb419vfwfg2 \
    --discovery-token-ca-cert-hash sha256:b3a573358f29f39c20a6e588481f150ea97cc2fe462331282dfc5cb34b88a06e \
    --control-plane

1.4.6 查看集群状态

① 检查etcd集群健康状态

ETCD=`docker ps|grep etcd|grep -v POD|awk '{print $1}'`
docker exec \
  -it ${ETCD} \
  etcdctl \
  --endpoints https://127.0.0.1:2379 \
  --cacert /etc/kubernetes/pki/etcd/ca.crt \
  --cert /etc/kubernetes/pki/etcd/peer.crt \
  --key /etc/kubernetes/pki/etcd/peer.key \
  member list

② 检查组件

kubectl get pods -n kube-system

1.4.7 设置污点

使Master参与POD资源负载

kubectl taint nodes master-02 node-role.kubernetes.io/master-
kubectl taint nodes master-03 node-role.kubernetes.io/master-

1.5 测试

1.5.1 打开haproxy状态页面

账号：admin 密码：123456 [在/etc/haproxy/haproxy.cfg中修改]

#Master-VIP
192.168.0.100:10080/status