双机keepalived高可用集群方案

 

一，双机高可用方案。

1，主机环境。

主机：IP：192.168.122.10，Centos7，MySQL5.7，nginx，keepalived，rsync

备机：IP：192.168.122.20，Centos7，MySQL5.7，nginx，keepalived，rsync

VIP：192.168.122.30

实现效果：两台主机配置mysql双主同步，nginx+rsync实现web资源实时双向同步，vip提供高可用，JAVA应用需手动同步。

2，业务系统高可用拓扑图

二，keepalived安装与配置。

1，keepalived简介

简单地说，keepalived 就是通过管理 VIP 来实现机器的高可用的，在使用 keepalived 的情况下，只有一台服务器能够提供服务(通过 VIP 来实现)，

当 Master 主机宕机后，VIP 会自动飘移到另一台服务器。

keepalived 采用 Master/Slave 模式, 在 Master 上设置配置文件的 VIP，当 Master 宕机后，VIP 自动漂移到另一台 keepalived 服务器上。

keepalived 可以用来做各种软件的高可用集群，它会一直检测服务器的状态，如果有一台服务器宕机，或工作出现故障，keepalived 将检测到，

并将有故障的服务器从系统中剔除，同时使用其他服务器代替该服务器的工作，当服务器工作正常后 keepalived 自动将服务器加入到服务器群中。

2，Yum 安装

yum install -y keepalived

3，源码安装

# 安装依赖
yum install -y gcc popt-devel openssl openssl-devel libssl-dev libnl-devel popt-devel libnfnetlink-devel

# 下载安装包
wget http://www.keepalived.org/software/keepalived-2.1.5.tar.gz

# 解压并安装
tar -xvz -f  keepalived-2.1.5.tar.gz
cd keepalived-2.1.5
./configure --prefix=/usr/local/keepalived
make && make install

cp /usr/local/keepalived/sbin/keepalived /usr/sbin/
cp /usr/local/keepalived/etc/rc.d/init.d/keepalived /etc/init.d/
cp /usr/local/keepalived/etc/sysconfig/keepalived /etc/sysconfig/
mkdir /etc/keepalived/
cp /usr/local/keepalived/etc/keepalived/keepalived.conf /etc/keepalived/

4，keepalived配置。

1），192.168.122.10主机/etc/keepalived.conf配置文件

! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state BACKUP
    nopreempt
  # preempt_delay 30
    interface eth0
    virtual_router_id 51
    priority 100
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.30
    }
}

virtual_server 192.168.122.30 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.10 80 {
        weight 1
        notify_down /etc/keepalived/shutdown.sh
        HTTP_GET {
            url {
              path /index.html
              status_code 200 
            }
            connect_port    80
            connect_timeout 3
            nb_get_retry    3
            delay_before_retry 3
        }
    }
}


virtual_server 192.168.122.30 3306 {
    delay_loop 7
    lb_algo rr 
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.10 3306 {
        weight 1
        notify_down /etc/keepalived/shutdown.sh
        TCP_CHECK { 
            connect_port 3306
            connect_timeout 2 
            nb_get_retry 3 
            delay_before_retry 3
      } 
  } 
}

2），192.168.122.10主机/etc/keepalived.conf配置文件

! Configuration File for keepalived

global_defs {
   notification_email {
     acassen@firewall.loc
     failover@firewall.loc
     sysadmin@firewall.loc
   }
   notification_email_from Alexandre.Cassen@firewall.loc
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
   vrrp_skip_check_adv_addr
   vrrp_strict
   vrrp_garp_interval 0
   vrrp_gna_interval 0
}

vrrp_instance VI_1 {
    state BACKUP
    nopreempt
  # preempt_delay 30    
    interface eth0
    virtual_router_id 51
    priority 99
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    virtual_ipaddress {
        192.168.122.30
    }
}

virtual_server 192.168.122.30 80 {
    delay_loop 6
    lb_algo rr
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.20 80 {
        weight 1
        notify_down /etc/keepalived/shutdown.sh
        HTTP_GET {
            url {
              path /index.html
              status_code 200 
            }
            connect_port 80
            connect_timeout 3
            nb_get_retry    3
            delay_before_retry 3
        }
    }
}


virtual_server 192.168.122.30 3306 {
    delay_loop 7
    lb_algo rr 
    lb_kind DR
    persistence_timeout 50
    protocol TCP

    real_server 192.168.122.20 3306 {
        weight 1
        notify_down /etc/keepalived/shutdown.sh
        TCP_CHECK { 
            connect_port 3306
            connect_timeout 2 
            nb_get_retry    3
            delay_before_retry 3
      } 
  } 
}

3），两台主机都是BACKUP角色，priority也可以一样，只是先启动keepalived的主机占用vip。

4），配置shutdown.sh脚本。脚本内容可根据情况调整。

[root@vm10 ~]# cat /etc/keepalived/shutdown.sh
#!/bin/bash
systemctl stop  keepalived

[root ~ ]#  chmod u+x /etc/keepalived/shutdown.sh
# 给关闭keepalived服务的脚本加执行权限

# nginx检测脚本样例

#!/bin/bash
A=`ps -C nginx --no-header |wc -l`
# 判断nginx是否宕机，如果宕机了，尝试重启
if [ $A -eq 0 ];then
    systemctl restart nginx
    # 等待一小会再次检查nginx，如果没有启动成功，则停止keepalived，使其启动备用机
    sleep 3
    if [ `ps -C nginx --no-header |wc -l` -eq 0 ];then
        killall keepalived
    fi
fi

三，启动keepalived并测试集群。

1，启动keepalived服务。

[root@vm20 ~]# for i in vm10 vm20; do ssh $i 'systemctl enable keepalived && systemctl restart keepalived';done
[root@vm20 ~]# ip addr2: eth0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP group default qlen 1000    link/ether 52:54:00:4f:f2:73 brd ff:ff:ff:ff:ff:ff    inet 192.168.122.20/24 brd 192.168.122.255 scope global noprefixroute eth0       valid_lft forever preferred_lft forever    inet 192.168.122.30/32 scope global eth0       valid_lft forever preferred_lft forever

# 查看vip 192.168.122.30 已经绑定到优先级高或是先启动keepalived服务的主机上。 

2，测试vip漂移是否正常。

在一台主机关闭nginx或是mysql服务，查看vip是否漂移到另外一台主机上面，故障主机的keepalived是否关闭。