18.3/18.4/18.5 用keepalived配置高可用集群

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用keepalived配置高可用集群

准备两台机器130和132，130作为master，132作为backup
两台机器都执行yum install -y keepalived
两台机器都安装nginx，其中130上已经编译安装过nginx，132上需要yum安装nginx: yum install -y nginx
设定vip为100
编辑130上keepalived配置文件，内容获取地址
130编辑监控脚本，内容获取地址
给脚本755权限
systemctl start keepalived 130启动服务
132上编辑配置文件，内容获取地址
132上编辑监控脚本，内容获取地址
给脚本755权限
132上也启动服务 systemctl start keepalived

keepalived配置高可用集群

首先准备两台机器，都安装keepalived

keepalived，实际是包含一个服务的，也就是说这个服务用来实现高可用

A机器，安装keepalived
[root@hanfeng ~]# yum install -y keepalived

B机器，安装keepalived
[root@hf-01 ~]# yum install -y keepalived

这里使用 nginx ，把它作为一个高可用的对象——>使用nginx作为演示对象的原因，因为nginx在工作中，在生产环境中，很多企业把nginx做一个负载均衡器

假设nginx一旦挂掉，那么后端所有的web，即使说是正常的，那也无法访问到

若是A、B机器没有装nginx服务，可以直接 yum安装

若是lnmp安装过nginx，则不需要安装了（源码包安装的nginx）
直接yum安装的nginx，两者很容易区分（PS：有时直接yum安装不了，需要安装yum扩展源——>yum install -y epel-release）
源码包安装nginx
源码安装nginx经常出现的错误

A机器源码安装nginx
（PS：有时初始化的时候，会看到无法初始化，是因为缺少一些包yum install  -y gcc）

B机器yum安装nginx
[root@hf-01 ~]# yum install -y epel-release
[root@hf-01 ~]# yum install -y nginx
[root@hf-01 ~]# systemctl start nginx
[root@hf-01 ~]# ps aux |grep nginx
root      2825  0.0  0.2 123300  2100 ?        Ss   11:40   0:00 nginx: master process /usr/sbin/nginx
nginx     2826  0.0  0.3 123764  3120 ?        S    11:40   0:00 nginx: worker process
root      2828  0.0  0.0 112656   992 pts/0    R+   11:40   0:00 grep --color=auto nginx
[root@hf-01 ~]#

更改keepalived配置文件了，内容地址

默认的配置文件路径在/etc/keepalived/keepalived.conf
清空文件的快捷键方法 > !$

A机器更改配置文件
[root@hanfeng ~]# ls /etc/keepalived/keepalived.conf 
/etc/keepalived/keepalived.conf
[root@hanfeng ~]# > !$        //直接清空文件内容了
> /etc/keepalived/keepalived.conf
[root@hanfeng ~]# cat /etc/keepalived/keepalived.conf
[root@hanfeng ~]# vim /etc/keepalived/keepalived.conf   //去文件地址去下载内容
将拷贝的内容复制进去
只需要改网卡名字和飘逸IP为192.168.133.100
####################### #  全局配置 #######################
global_defs {                            //global_defs 全局配置标识
   notification_email {               //notification_email用于设置报警邮件地址
[email protected]           //可以设置多个，每行一个
   }
   notification_email_from [email protected]    //设置邮件发送地址  
   smtp_server 127.0.0.1                //设置邮件的smtp server地址
   smtp_connect_timeout 30            //设置连接smtp sever超时时间
   router_id LVS_DEVEL
}

###################### #  VRRP配置 ######################
vrrp_script chk_nginx {               
    script "/usr/local/sbin/check_ng.sh"   //检查服务是否正常，通过写脚本实现，脚本检查服务健康状态
    interval 3                      //检查的时间间断是3秒
}
vrrp_instance VI_1 {                        //VRRP配置标识 VI_1是实例名称 
    state MASTER                           //定义master相关
    interface eno16777736                        //通过vrrp协议去通信、去发广播。配置时，需注意自己的网卡名称
    virtual_router_id 51                   //定义路由器ID ，配置的时候和从机器一致
    priority 100                              //权重，主角色和从角色的权重是不同的
    advert_int 1                            //设定MASTER与BACKUP主机质检同步检查的时间间隔，单位为秒
    authentication {                       //认证相关信息
        auth_type PASS                   //这里认证的类型是PASS
        auth_pass aminglinux>com   //密码的形式是一个字符串
    }
    virtual_ipaddress {                  //设置虚拟IP地址 (VIP),又叫做漂移IP地址
        192.168.74.100   //更改为192.168.74.100
    }
    track_script {               //加载脚本 
        chk_nginx            
    }
}

保存退出

virtual_ipaddress：简称VIP，这个vip，两台机器，一个主，一个从，正常的情况是主在服务，主宕掉了，从起来了，从启动服务，从启动nginx以后，，启动以后，访问那个IP呢？把域名解析到那个IP上呢？假如解析到主上，主宕掉了，所以这个，需要定义一个公有IP（主上用的IP，从上也用的IP）；这个IP是随时可以夏掉，去配置的

定义监控脚本，脚本内容获取地址

脚本路径在keepalived配置文件中有定义，路径为/usr/local/sbin/check_ng.sh

A机器定义监控脚本
[root@hanfeng ~]# vim /usr/local/sbin/check_ng.sh

#!/bin/bash
#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        /etc/init.d/nginx start
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log
                systemctl stop keepalived
        fi
fi

保存退出

“脑裂”，在高可用（HA）系统中，当联系2个节点的“心跳线”断开时，本来为一整体、动作协调的HA系统，就分裂成为2个独立的个体。由于相互失去了联系，都以为是对方出了故障。两个节点上的HA软件像“裂脑人”一样，争抢“共享资源”、争起“应用服务”，就会发生严重后果——或者共享资源被瓜分、2边“服务”都起不来了；或者2边“服务”都起来了，但同时读写“共享存储”，导致数据损坏
如何判断脑裂？
- 分别在两台机查看当前服务器是否拥有虚拟IP，如果两台服务器都拥有，则说明发生了脑裂，证明目前双机通信出现问题，产生此问题的原有在于两台服务器都探测不到组内其他服务器的状态（心跳请求无法正常响应），私自判定另一台服务器挂起，则抢占虚拟IP，脑裂的出现是不被允许的，解决此问题的方法为检查防火墙设置（关闭防火墙）或者使用串口通信。

脚本创建完之后，还需要改变脚本的权限（不更改权限，就无法自动加载脚本，那就无法启动keepalived服务）

[root@hanfeng ~]# chmod 755 /usr/local/sbin/check_ng.sh
[root@hanfeng ~]#

启动keepalived服务，并查看是否启动成功（PS：启动不成功，有可能是防火墙未关闭或者规则限制导致的）

systemctl stop firewalld 关闭firewalld
iptables -nvL
setenforce 0 临时关闭selinux
getenforce命令查看是否为Permissive
这时再来启动keepalived，就会看到keepalived进程服务了

[root@hanfeng ~]# systemctl start keepalived
[root@hanfeng ~]# ps aux |grep keepalived
root      2970  0.0  0.1 121324  1404 ?        Ss   07:14   0:00 /usr/sbin/keepalived -D
root      2971  0.0  0.2 123396  2356 ?        S    07:14   0:00 /usr/sbin/keepalived -D
root      2972  0.0  0.2 123396  2384 ?        S    07:14   0:00 /usr/sbin/keepalived -D
root      2974  0.0  0.0 112672   988 pts/1    R+   07:14   0:00 grep --color=auto keepalived
[root@hanfeng ~]#

查看nginx服务进程

[root@hanfeng ~]# ps aux |grep nginx
root      3004  0.0  0.2 123372  2108 ?        Ss   07:18   0:00 nginx: master process /usr/sbin/nginx
nginx     3005  0.0  0.3 123836  3148 ?        S    07:18   0:00 nginx: worker process
root      3007  0.0  0.0 112672   984 pts/1    R+   07:19   0:00 grep --color=auto nginx
[root@hanfeng ~]#

这时停止nginx服务

/etc/init.d/nginx stop

[root@hanfeng ~]# /etc/init.d/nginx stop
Stopping nginx (via systemctl):                            [  确定  ]
[root@hanfeng ~]#

再来查看nginx服务进程，会看到自动加载了

[root@hanfeng ~]# ps aux |grep nginx
root      6238  0.0  0.0  20996   628 ?        Ss   08:07   0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
nobody    6242  0.0  0.3  23440  3212 ?        S    08:07   0:00 nginx: worker process
nobody    6243  0.0  0.3  23440  3212 ?        S    08:07   0:00 nginx: worker process
root      6263  0.0  0.0 112676   980 pts/0    R+   08:07   0:00 grep --color=auto nginx
[root@hanfeng ~]#

keepalived日志文件路径

/var/log/messages

查看ip地址，使用 ip add 命令，而不能使用ifconfig命令，因为 ifconfig命令是无法查看到vip192.168.133.100这个IP的

[root@hanfeng ~]# ip add
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    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: eno16777736:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c7:05:28 brd ff:ff:ff:ff:ff:ff
    inet 192.168.74.130/24 brd 192.168.74.255 scope global dynamic eno16777736
       valid_lft 1158sec preferred_lft 1158sec
    inet 192.168.133.100/32 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fec7:528/64 scope link 
       valid_lft forever preferred_lft forever
[root@hanfeng ~]#

检查A、B 机器下防火墙和selinux是否关闭了，若没有关闭，可能会导致实验失败

systemctl stop firewalld 关闭firewalld
iptables -nvL
setenforce 0 临时关闭selinux
getenforce命令查看是否为Permissive

以上就是主机器A的配置

backup 机器配置

在B机器yum安装nginx和keepalived

[root@hf-01 ~]# yum install -y epel-release
[root@hf-01 ~]# yum install -y nginx

关闭B机器的防火墙和selinux

iptables -F 清空规则
setenforce 0 临时关闭selinux

自定义B机器keepalived配置文件，内容获取地址，更改虚拟IP和主一样的

首先清空B机器keepalived里面自带的配置文件
[root@hf-01 ~]# > /etc/keepalived/keepalived.conf 
[root@hf-01 ~]# cat !$
cat /etc/keepalived/keepalived.conf
[root@hf-01 ~]# 

然后复制配置文件并粘贴进去，更改虚拟IP和主一样的
[root@hf-01 ~]# vim /etc/keepalived/keepalived.conf


global_defs {
   notification_email {
     [email protected]
   }
   notification_email_from [email protected]
   smtp_server 127.0.0.1
   smtp_connect_timeout 30
   router_id LVS_DEVEL
}
vrrp_script chk_nginx {
    script "/usr/local/sbin/check_ng.sh"
    interval 3
}
vrrp_instance VI_1 {
    state BACKUP        //这里 和master不一样的名字
    interface eno16777736        //网卡和当前机器一致，否则无法启动keepalived服务
    virtual_router_id 51        //和主机器 保持一致
    priority 90            //权重，要比主机器小的数值
    advert_int 1
    authentication {
        auth_type PASS
        auth_pass aminglinux>com
    }
    virtual_ipaddress {
        192.168.74.100        //这里更改为192.168.74.100
    }
    track_script {
        chk_nginx
    }
}

保存退出

定义监控脚本，路径再keepalived里面已定义过，脚本内容地址

这个脚本和主上的脚本有一点区别，启动nginx的命令不同，因为一个是yum安装，一个是源码包安装

[root@hf-01 ~]# vim /usr/local/sbin/check_ng.sh

#时间变量，用于记录日志
d=`date --date today +%Y%m%d_%H:%M:%S`
#计算nginx进程数量
n=`ps -C nginx --no-heading|wc -l`
#如果进程为0，则启动nginx，并且再次检测nginx进程数量，
#如果还为0，说明nginx无法启动，此时需要关闭keepalived
if [ $n -eq "0" ]; then
        systemctl start nginx
        n2=`ps -C nginx --no-heading|wc -l`
        if [ $n2 -eq "0"  ]; then
                echo "$d nginx down,keepalived will stop" >> /var/log/check_ng.log                systemctl stop keepalived
        fi
fi
保存退出

改动脚本的权限，设置为755权限

[root@hf-01 ~]# chmod 755 /usr/local/sbin/check_ng.sh
[root@hf-01 ~]#

B机器启动keepalived服务

systemctl start keepalived

[root@hf-01 ~]# systemctl start keepalived
[root@hf-01 ~]# ps aux |grep keep
root      2814  0.0  0.1 121324  1396 ?        Ss   07:10   0:00 /usr/sbin/keepalived -D
root      2815  0.0  0.2 121324  2740 ?        S    07:10   0:00 /usr/sbin/keepalived -D
root      2816  0.0  0.2 121324  2324 ?        S    07:10   0:00 /usr/sbin/keepalived -D
root      2827  0.0  0.0 112672   980 pts/0    R+   07:10   0:00 grep --color=auto keep
[root@hf-01 ~]#

如何区分主和从上的nginx？

A机器，是源码包安装的nginx（PS：这是lnmp配置好的环境虚拟主机内容）

[root@hanfeng ~]# cat /usr/local/nginx/conf/vhost/aaa.com.conf
server
{
    listen 80 default_server; 
    server_name aaa.com;
    index index.html index.htm index.php;
    root /data/wwwroot/default;
 location ~ \.php$
    {
        include fastcgi_params;
        fastcgi_pass unix:/tmp/champ.sock;
       #fastcgi_pass 127.0.0.1:9000;
        fastcgi_index index.php;
        fastcgi_param SCRIPT_FILENAME /data/wwwroot/default$fastcgi_script_name;
    }

}

[root@hanfeng ~]# cat /data/wwwroot/default/index.html 
This is the default sete.
[root@cham002 ~]# vim /data/wwwroot/default/index.html 
master This is the default sete.
[root@cham002 ~]#

B机器是yum安装的nginx
- 默认的索引页在 /usr/share/nginx/html/index.html

[root@hf-02~]# cat /usr/share/nginx/html/index.html 
[root@hf-02 ~]# vim /usr/share/nginx/html/index.html 
backup backup.

![输入图片说明](https://static.oschina.net/uploads/img/201801/28233716_ovDw.png "backup机器访问IP")

访问192.168.74.100这个VIP会看到和主机器（即A机器相同的内容），说明现在访问到的是机器master，VIP在master上

问题-B机器无法调用nginx服务？

B机器关闭nginx服务，keepalived无法拉动nginx服务起来
解决方法：
- 再次设置755权限，就可以拉动nginx服务了

测试高可用

模拟线上生产环境，主机器宕机环境，最简单直接的方法，就是直接关闭keepalived服务
关闭master机器（即A机器）上的keepalived服务关闭

[root@hanfeng ~]# systemctl stop keepalived
[root@hanfeng ~]#

查看A机器上的VIP被已经释放掉了

[root@hanfeng ~]# ip add
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    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: eno16777736:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c7:05:28 brd ff:ff:ff:ff:ff:ff
    inet 192.168.74.130/24 brd 192.168.74.255 scope global dynamic eno16777736
       valid_lft 1219sec preferred_lft 1219sec
    inet6 fe80::20c:29ff:fec7:528/64 scope link 
       valid_lft forever preferred_lft forever
[root@hanfeng ~]#

查看backup机器（即B机器）在监听VIP

[root@hf-01 ~]# ip add
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    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: eno16777736:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:ff:fe:93 brd ff:ff:ff:ff:ff:ff
    inet 192.168.74.129/24 brd 192.168.74.255 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 192.168.74.100/32 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet 192.168.74.150/24 brd 192.168.74.255 scope global secondary eno16777736:0
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:feff:fe93/64 scope link 
       valid_lft forever preferred_lft forever
[root@hf-01 ~]#

查看B机器日志

[root@hf-01 ~]# tail /var/log/messages
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng avahi-daemon[568]: Registering new address record for 192.168.74.100 on eno16777736.IPv4.
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
[root@hf-01 ~]#

浏览器访问vip，会看到已经变成backup机器上的了
在master机器（即A机器）启动keepalived服务，会看到vip这个IP立刻回来了

[root@hanfeng ~]# systemctl start keepalived
[root@hanfeng ~]# ip add
1: lo:  mtu 65536 qdisc noqueue state UNKNOWN 
    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: eno16777736:  mtu 1500 qdisc pfifo_fast state UP qlen 1000
    link/ether 00:0c:29:c7:05:28 brd ff:ff:ff:ff:ff:ff
    inet 192.168.74.130/24 brd 192.168.74.255 scope global dynamic eno16777736
       valid_lft 1577sec preferred_lft 1577sec
    inet 192.168.74.100/32 scope global eno16777736
       valid_lft forever preferred_lft forever
    inet6 fe80::20c:29ff:fec7:528/64 scope link 
       valid_lft forever preferred_lft forever
[root@hanfeng ~]#

查看B机器日志变化

[root@hf-01 ~]# tail /var/log/messages
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:39 hanfeng avahi-daemon[568]: Registering new address record for 192.168.74.100 on eno16777736.IPv4.
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: VRRP_Instance(VI_1) Sending/queueing gratuitous ARPs on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
[root@hf-01 ~]# tail /var/log/messages
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:20:44 hanfeng Keepalived_vrrp[7886]: Sending gratuitous ARP on eno16777736 for 192.168.74.100
Jan 29 08:30:01 hanfeng systemd: Started Session 49 of user root.
Jan 29 08:30:01 hanfeng systemd: Starting Session 49 of user root.
Jan 29 08:30:51 hanfeng Keepalived_vrrp[7886]: VRRP_Instance(VI_1) Received advert with higher priority 100, ours 90
Jan 29 08:30:51 hanfeng Keepalived_vrrp[7886]: VRRP_Instance(VI_1) Entering BACKUP STATE
Jan 29 08:30:51 hanfeng Keepalived_vrrp[7886]: VRRP_Instance(VI_1) removing protocol VIPs.
Jan 29 08:30:51 hanfeng avahi-daemon[568]: Withdrawing address record for 192.168.74.100 on eno16777736.
[root@hf-01 ~]#

##总结

在生产环境中，可能会用到2-3台backup角色, vim /etc/keepalived/keepalived.conf 这里面的权重调成不通级别，权重越高优先级越高！除了nginx服务的话，还可以做MySQL的高可用集群服务。（做mysql的高可用，一定要保证两边的数据一致）

18.3/18.4/18.5 用keepalived配置高可用集群

用keepalived配置高可用集群

keepalived配置高可用集群

以上就是主机器A的配置

backup 机器配置

如何区分主和从上的nginx？

问题-B机器无法调用nginx服务？

测试高可用

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