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keepalived高可用

2019-09-23 10:06:20 阅读：195 来源： 互联网

标签：slave 可用 keepalived 192.168 nginx master root

keepalived高可用

文章目录

keepalived高可用

1. keepalived的重要功能
2. keepalived高可用故障转移的原理
3. keepalived工作原理描述
4. keepalived默认配置文件
5. keepalived实现nginx负载均衡机高可用

5.1 keepalived安装
5.2 在主备机上分别安装nginx
5.3 keepalived配置
5.4 查看VIP在哪里
5.5修改内核参数，开启监听VIP功能
5.6让keepalived监控nginx负载均衡机
5.6 配置keepalived加入监控脚本的配置

1. keepalived的重要功能

keepalived 有三个重要的功能，分别是：

管理LVS负载均衡软件
实现LVS集群节点的健康检查
作为系统网络服务的高可用性（failover）

2. keepalived高可用故障转移的原理

Keepalived 高可用服务之间的故障切换转移，是通过 VRRP (Virtual Router Redundancy Protocol ,虚拟路由器冗余协议）来实现的。

在 Keepalived 服务正常工作时，主 Master 节点会不断地向备节点发送（多播的方式）心跳消息，用以告诉备 Backup 节点自己还活看，当主 Master 节点发生故障时，就无法发送心跳消息，备节点也就因此无法继续检测到来自主 Master 节点的心跳了，于是调用自身的接管程序，接管主 Master 节点的 IP 资源及服务。而当主 Master 节点恢复时，备 Backup 节点又会释放主节点故障时自身接管的IP资源及服务，恢复到原来的备用角色。

那么，什么是VRRP呢？
VRRP ,全称 Virtual Router Redundancy Protocol ,中文名为虚拟路由冗余协议，VRRP的出现就是为了解决静态踣甶的单点故障问题，VRRP是通过一种竞选机制来将路由的任务交给某台VRRP路由器的。

3. keepalived工作原理描述

Keepalived高可用对之间是通过VRRP通信的，因此，我们从 VRRP开始了解起：

VRRP,全称 Virtual Router Redundancy Protocol,中文名为虚拟路由冗余协议，VRRP的出现是为了解决静态路由的单点故障。
VRRP是通过一种竟选协议机制来将路由任务交给某台 VRRP路由器的。
VRRP用 IP多播的方式（默认多播地址（224.0_0.18))实现高可用对之间通信。
工作时主节点发包，备节点接包，当备节点接收不到主节点发的数据包的时候，就启动接管程序接管主节点的开源。备节点可以有多个，通过优先级竞选，但一般 Keepalived系统运维工作中都是一对。
VRRP使用了加密协议加密数据，但Keepalived官方目前还是推荐用明文的方式配置认证类型和密码。

介绍完 VRRP,接下来我再介绍一下 Keepalived服务的工作原理：

Keepalived高可用是通过 VRRP 进行通信的， VRRP是通过竞选机制来确定主备的，主的优先级高于备，因此，工作时主会优先获得所有的资源，备节点处于等待状态，当主挂了的时候，备节点就会接管主节点的资源，然后顶替主节点对外提供服务。

在 Keepalived 服务之间，只有作为主的服务器会一直发送 VRRP 广播包,告诉备它还活着，此时备不会枪占主，当主不可用时，即备监听不到主发送的广播包时，就会启动相关服务接管资源，保证业务的连续性.接管速度最快可以小于1秒。

4. keepalived默认配置文件

keepalived 的主配置文件是 /etc/keepalived/keepalived.conf。其内容如下：

[root@master ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {       //全局配置
   notification_email {     //定义报警收件人邮件地址
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc    //定义报警发件人邮箱
   smtp_server 192.168.200.1    //邮箱服务器地址
   smtp_connect_timeout 30      //定义邮箱超时时间
   router_id LVS_DEVEL          //定义路由标识信息，同局域网内唯一
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {        //定义实例
    state MASTER            //指定keepalived节点的初始状态，可选值为MASTER|BACKUP
    interface eth0          //VRRP实例绑定的网卡接口，用户发送VRRP包
    virtual_router_id 51    //虚拟路由的ID，同一集群要一致
    priority 100            //定义优先级，按优先级来决定主备角色，优先级越大越优先
    nopreempt               //设置不抢占
    advert_int 1            //主备通讯时间间隔
    authentication {        //配置认证
        auth_type PASS      //认证方式，此处为密码
        auth_pass 1111      //同一集群中的keepalived配置里的此处必须一致，推荐使用8位随机数
    }
    virtual_ipaddress {     //配置要使用的VIP地址
        192.168.200.16
    }
}

virtual_server 192.168.200.16 1358 {    //配置虚拟服务器
    delay_loop 6        //健康检查的时间间隔
    lb_algo rr          //lvs调度算法
    lb_kind NAT         //lvs模式
    persistence_timeout 50      //持久化超时时间，单位是秒
    protocol TCP        //4层协议

    sorry_server 192.168.200.200 1358   //定义备用服务器，当所有RS都故障时用sorry_server来响应客户端

    real_server 192.168.200.2 1358 {    //定义真实处理请求的服务器
        weight 1    //给服务器指定权重，默认为1
        HTTP_GET {
            url {
              path /testurl/test.jsp    //指定要检查的URL路径
              digest 640205b7b0fc66c1ea91c463fac6334d   //摘要信息
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            url {
              path /testurl3/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334d
            }
            connect_timeout 3       //连接超时时间
            nb_get_retry 3          //get尝试次数
            delay_before_retry 3    //在尝试之前延迟多长时间
        }
    }

    real_server 192.168.200.3 1358 {
        weight 1
        HTTP_GET {
            url {
              path /testurl/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            url {
              path /testurl2/test.jsp
              digest 640205b7b0fc66c1ea91c463fac6334c
            }
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

5. keepalived实现nginx负载均衡机高可用

环境说明

系统信息	主机名	IP
centos7	master	192.168.76.131
ccentos7	slave	192.168.76.132

高可用虚拟IP暂定为 192.168.76.250

5.1 keepalived安装

配置主keepalived

//关闭防火墙与SELINUX
[root@master ~]# systemctl stop firewalld
[root@master ~]# systemctl disable firewalld
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slave ~]# getenforce
Disabled


//配置网络源
[root@master ~]# curl -o /etc/yum.repos.d/CentOS7-Base-163.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo
[root@master ~]# sed -i 's/\$releasever/7/g' /etc/yum.repos.d/CentOS7-Base-163.repo
[root@master ~]# sed -i 's/^enabled=.*/enabled=1/g' /etc/yum.repos.d/CentOS7-Base-163.repo
[root@master ~]# yum -y install epel-release vim wget gcc gcc-c++
安装过程略.....

//安装keepalived
[root@master ~]# yum -y install keepalived

配置副keepalived

//关闭防火墙与SELINUX
[root@slave ~]# systemctl stop firewalld
[root@slave ~]# systemctl disable firewalld
Removed symlink /etc/systemd/system/multi-user.target.wants/firewalld.service.
Removed symlink /etc/systemd/system/dbus-org.fedoraproject.FirewallD1.service.
[root@slave ~]# getenforce
Disabled


//配置网络源
[root@slave ~]# curl -o /etc/yum.repos.d/CentOS7-Base-163.repo http://mirrors.163.com/.help/CentOS7-Base-163.repo
[root@slave ~]# sed -i 's/\$releasever/7/g' /etc/yum.repos.d/CentOS7-Base-163.repo
[root@slave ~]# sed -i 's/^enabled=.*/enabled=1/g' /etc/yum.repos.d/CentOS7-Base-163.repo
[root@slave ~]# yum -y install epel-release vim wget gcc gcc-c++
安装过程略.....

//安装keepalived
[root@slave ~]# yum -y install keepalived

5.2 在主备机上分别安装nginx

在master上安装nginx

[root@master ~]# yum -y install nginx
[root@master ~]# cd /usr/share/nginx/html/
[root@master html]# ls
404.html  50x.html  index.html  nginx-logo.png  poweredby.png
[root@master html]# mv index.html{,.bak}
[root@master html]# echo 'master' > index.html
[root@master html]# ls
404.html  50x.html  index.html  index.html.bak  nginx-logo.png  poweredby.png
[root@master html]# systemctl start nginx
[root@master html]# systemctl enable nginx
[root@master html]# ss -antl
State       Recv-Q Send-Q Local Address:Port               Peer Address:Port
LISTEN      0      128              *:80                           *:*
LISTEN      0      128              *:22                           *:*
LISTEN      0      100      127.0.0.1:25                           *:*
LISTEN      0      128             :::80                          :::*
LISTEN      0      128             :::22                          :::*
LISTEN      0      100            ::1:25                          :::*

在slave上安装nginx

[root@slave ~]# yum -y install nginx
[root@slave ~]# cd /usr/share/nginx/html/
[root@slave html]# ls
404.html  50x.html  index.html  nginx-logo.png  poweredby.png
[root@slave html]# mv index.html{,.bak}
[root@slave html]# echo 'slave' > index.html
[root@slave html]# ls
404.html  50x.html  index.html  index.html.bak  nginx-logo.png  poweredby.png
[root@slave html]# systemctl start nginx
[root@slave html]# systemctl enable nginx

5.3 keepalived配置

配置主keepalived

[root@master ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id hd1
}

vrrp_instance VI_1 {
    state MASTER
    interface ens32
    virtual_router_id 66
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass hua
    }
    virtual_ipaddress {
        192.168.76.250
    }
}

virtual_server 192.168.76.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.76.131 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.76.132 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@master ~]# systemctl start keepalived
[root@master ~]# systemctl enable keepalived

配置备keepalived

[root@slave ~]# cat /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id hd2
}

vrrp_instance VI_1 {
    state BACKUP
    interface ens32
    virtual_router_id 66
    priority 90
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass hua
    }
    virtual_ipaddress {
        192.168.76.250
    }
}

virtual_server 192.168.76.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.76.131 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.76.132 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}
[root@slave ~]# systemctl start keepalived
[root@slave ~]# systemctl enable keepalived

5.4 查看VIP在哪里

[root@hua ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:ca:e9:03 brd ff:ff:ff:ff:ff:ff
    inet 192.168.76.131/24 brd 192.168.76.255 scope global ens32
       valid_lft forever preferred_lft forever
    inet 192.168.76.250/32 scope global ens32     //可以看到此处有VIP
       valid_lft forever preferred_lft forever

把主keepalived关掉

[root@master ~]# systemctl stop keepalived

在备上看250过去没有

[root@slave ~]# ip a
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN qlen 1
    link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
    inet 127.0.0.1/8 scope host lo
       valid_lft forever preferred_lft forever
    inet6 ::1/128 scope host 
       valid_lft forever preferred_lft forever
2: ens32: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:b9:f1:6b brd ff:ff:ff:ff:ff:ff
    inet 192.168.76.132/24 brd 192.168.76.255 scope global ens32
       valid_lft forever preferred_lft forever
    inet 192.168.76.250/32 scope global ens32
       valid_lft forever preferred_lft forever

5.5修改内核参数，开启监听VIP功能

此步可做可不做，该功能可用于仅监听VIP的时候
在master上修改内核参数

[root@master ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
[root@master ~]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@master ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind
1

在slave上修改内核参数

[root@slave ~]# echo 'net.ipv4.ip_nonlocal_bind = 1' >>/etc/sysctl.conf
[root@slave ~]# sysctl -p
net.ipv4.ip_nonlocal_bind = 1
[root@slave ~]# cat /proc/sys/net/ipv4/ip_nonlocal_bind
1

5.6让keepalived监控nginx负载均衡机

keepalived通过脚本来监控nginx负载均衡机的状态

在master上编写脚本

[root@master ~]# mkdir /scripts
[root@master ~]# cd /scripts/
[root@master scripts]# vim check_n.sh
#!/bin/bash
nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
if [ $nginx_status -lt 1 ];then
    systemctl stop keepalived
fi

[root@master scripts]# chmod +x check_n.sh
[root@master scripts]# ll
total 4
-rwxr-xr-x 1 root root 168 Oct 19 23:38 check_n.sh

[root@master scripts]# vim notify.sh
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" 1470044516@qq.com
}
case "$1" in
  master)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -lt 1 ];then
            systemctl start nginx
        fi
        sendmail
  ;;
  backup)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -gt 0 ];then
            systemctl stop nginx
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac

[root@master scripts]# chmod +x notify.sh
[root@master scripts]# ll
total 8
-rwxr-xr-x 1 root root 168 Oct 19 23:38 check_n.sh
-rwxr-xr-x 1 root root 594 Oct 20 03:24 notify.sh

在slave上编写脚本

[root@slave ~]# mkdir /scripts
[root@slave ~]# cd /scripts/
[root@slave scripts]# vim notify.sh
#!/bin/bash
VIP=$2
sendmail (){
        subject="${VIP}'s server keepalived state is translate"
        content="`date +'%F %T'`: `hostname`'s state change to master"
        echo $content | mail -s "$subject" 1470044516@qq.com
}
case "$1" in
  master)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -lt 1 ];then
            systemctl start nginx
        fi
        sendmail
  ;;
  backup)
        nginx_status=$(ps -ef|grep -Ev "grep|$0"|grep '\bnginx\b'|wc -l)
        if [ $nginx_status -gt 0 ];then
            systemctl stop nginx
        fi
  ;;
  *)
        echo "Usage:$0 master|backup VIP"
  ;;
esac

[root@slave scripts]# chmod +x notify.sh
[root@slave scripts]# ll
total 8
-rwxr-xr-x 1 root root 168 Oct 19 23:38 check_n.sh
-rwxr-xr-x 1 root root 594 Oct 20 03:24 notify.sh

此处的脚本名称应避免与服务名相同，推荐用服务名的首字母代替，如check_n，不要给脚本起名check_nginx

5.6 配置keepalived加入监控脚本的配置

配置主keepalived

[root@master ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb01
}

vrrp_script nginx_check {
    script "/scripts/check_n.sh"
    interval 1
    weight -20
}

vrrp_instance VI_1 {
    state MASTER
    interface ens33
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wangqing
    }
    virtual_ipaddress {
        192.168.76.250
    }
    track_script {
        nginx_check
    }
    notify_master "/scripts/notify.sh master 192.168.76.250"
    notify_backup "/scripts/notify.sh backup 192.168.76.250"
}

virtual_server 192.168.76.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.76.131 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.76.132 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@master ~]# systemctl restart keepalived

配置备keepalived
backup无需检测nginx是否正常，当升级为MASTER时启动nginx，当降级为BACKUP时关闭

[root@slave ~]# vim /etc/keepalived/keepalived.conf
! Configuration File for keepalived

global_defs {
   router_id lb02
}

vrrp_instance VI_1 {
    state BACKUP
    interface eth0
    virtual_router_id 51
    priority 90
    nopreempt
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass wangqing
    }
    virtual_ipaddress {
        192.168.76.250
    }
    notify_master "/scripts/notify.sh master 192.168.76.250"
    notify_backup "/scripts/notify.sh backup 192.168.76.250"
}

virtual_server 192.168.76.250 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.76.131 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }

    real_server 192.168.76.132 80 {
        weight 1
        TCP_CHECK {
            connect_port 80
            connect_timeout 3
            nb_get_retry 3
            delay_before_retry 3
        }
    }
}

[root@slave ~]# systemctl restart keepalived

标签：slave,可用,keepalived,192.168,nginx,master,root
来源： https://blog.csdn.net/weixin_44245976/article/details/100349453

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keepalived高可用

keepalived高可用

文章目录

1. keepalived的重要功能

2. keepalived高可用故障转移的原理

3. keepalived工作原理描述

4. keepalived默认配置文件

5. keepalived实现nginx负载均衡机高可用

5.1 keepalived安装

5.2 在主备机上分别安装nginx

5.3 keepalived配置

5.4 查看VIP在哪里

5.5修改内核参数，开启监听VIP功能

5.6让keepalived监控nginx负载均衡机

5.6 配置keepalived加入监控脚本的配置