• 部署高可用keepalived组件


     

    本文档讲解使用 keepalived 和 haproxy 实现 kube-apiserver 高可用的步骤:

    • keepalived 提供 kube-apiserver 对外服务的 VIP;
    • haproxy 监听 VIP,后端连接所有 kube-apiserver 实例,提供健康检查和负载均衡功能;

    运行 keepalived 和 haproxy 的节点称为 LB 节点。由于 keepalived 是一主多备运行模式,故至少两个 LB 节点。

    本文档复用 master 节点的三台机器,haproxy 监听的端口(8443) 需要与 kube-apiserver 的端口 6443 不同,避免冲突。

    keepalived 在运行过程中周期检查本机的 haproxy 进程状态,如果检测到 haproxy 进程异常,则触发重新选主的过程,VIP 将飘移到新选出来的主节点,从而实现 VIP 的高可用。

    所有组件(如 kubeclt、apiserver、controller-manager、scheduler 等)都通过 VIP 和 haproxy 监听的 8443 端口访问 kube-apiserver 服务。

    安装软件包

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "yum install -y keepalived haproxy"
      done

    配置和下发 haproxy 配置文件

    haproxy 配置文件:

    cat > haproxy.cfg <<EOF
    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 172.27.129.105 172.27.129.105:6443 check inter 2000 fall 2 rise 2 weight 1
        server 172.27.129.111 172.27.129.111:6443 check inter 2000 fall 2 rise 2 weight 1
        server 172.27.129.112 172.27.129.112:6443 check inter 2000 fall 2 rise 2 weight 1
    EOF
    • haproxy 在 10080 端口输出 status 信息;
    • haproxy 监听所有接口的 8443 端口,该端口与环境变量 ${KUBE_APISERVER} 指定的端口必须一致;
    • server 字段列出所有 kube-apiserver 监听的 IP 和端口;

    下发 haproxy.cfg 到所有 master 节点:

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        scp haproxy.cfg root@${node_ip}:/etc/haproxy
      done

    起 haproxy 服务

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "systemctl restart haproxy"
      done

    检查 haproxy 服务状态

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "systemctl status haproxy|grep Active"
      done

    确保状态为 active (running),否则查看日志,确认原因:

    journalctl -u haproxy

    检查 haproxy 是否监听 8443 端口:

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "netstat -lnpt|grep haproxy"
      done

    确保输出类似于:

    tcp        0      0 0.0.0.0:8443            0.0.0.0:*               LISTEN      120583/haproxy

    配置和下发 keepalived 配置文件

    keepalived 是一主(master)多备(backup)运行模式,故有两种类型的配置文件。master 配置文件只有一份,backup 配置文件视节点数目而定,对于本文档而言,规划如下:

    • master: 172.27.129.105
    • backup:172.27.129.111、172.27.129.112

    master 配置文件:

    source /opt/k8s/bin/environment.sh
    cat  > keepalived-master.conf <<EOF
    global_defs {
        router_id lb-master-105
    }
    
    vrrp_script check-haproxy {
        script "killall -0 haproxy"
        interval 5
        weight -30
    }
    
    vrrp_instance VI-kube-master {
        state MASTER
        priority 120
        dont_track_primary
        interface ${VIP_IF}
        virtual_router_id 68
        advert_int 3
        track_script {
            check-haproxy
        }
        virtual_ipaddress {
            ${MASTER_VIP}
        }
    }
    EOF
    • VIP 所在的接口(interface ${VIP_IF})为 eth0
    • 使用 killall -0 haproxy 命令检查所在节点的 haproxy 进程是否正常。如果异常则将权重减少(-30),从而触发重新选主过程;
    • router_id、virtual_router_id 用于标识属于该 HA 的 keepalived 实例,如果有多套 keepalived HA,则必须各不相同;

    backup 配置文件:

    source /opt/k8s/bin/environment.sh
    cat  > keepalived-backup.conf <<EOF
    global_defs {
        router_id lb-backup-105
    }
    
    vrrp_script check-haproxy {
        script "killall -0 haproxy"
        interval 5
        weight -30
    }
    
    vrrp_instance VI-kube-master {
        state BACKUP
        priority 110
        dont_track_primary
        interface ${VIP_IF}
        virtual_router_id 68
        advert_int 3
        track_script {
            check-haproxy
        }
        virtual_ipaddress {
            ${MASTER_VIP}
        }
    }
    EOF
    • VIP 所在的接口(interface ${VIP_IF})为 eth0
    • 使用 killall -0 haproxy 命令检查所在节点的 haproxy 进程是否正常。如果异常则将权重减少(-30),从而触发重新选主过程;
    • router_id、virtual_router_id 用于标识属于该 HA 的 keepalived 实例,如果有多套 keepalived HA,则必须各不相同;
    • priority 的值必须小于 master 的值;

    下发 keepalived 配置文件

    下发 master 配置文件:

    scp keepalived-master.conf root@172.27.129.105:/etc/keepalived/keepalived.conf

    下发 backup 配置文件:

    scp keepalived-backup.conf root@172.27.129.111:/etc/keepalived/keepalived.conf
    scp keepalived-backup.conf root@172.27.129.112:/etc/keepalived/keepalived.conf

    起 keepalived 服务

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "systemctl restart keepalived"
      done

    检查 keepalived 服务

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh root@${node_ip} "systemctl status keepalived|grep Active"
      done

    确保状态为 active (running),否则查看日志,确认原因:

    journalctl -u keepalived

    查看 VIP 所在的节点,确保可以 ping 通 VIP:

    source /opt/k8s/bin/environment.sh
    for node_ip in ${NODE_IPS[@]}
      do
        echo ">>> ${node_ip}"
        ssh ${node_ip} "/usr/sbin/ip addr show ${VIP_IF}"
        ssh ${node_ip} "ping -c 1 ${MASTER_VIP}"
      done

    查看 haproxy 状态页面

    浏览器访问 ${MASTER_VIP}:10080/status 地址,查看 haproxy 状态页面:

    haproxy

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  • 原文地址:https://www.cnblogs.com/cheyunhua/p/10036620.html
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