keepalive+nginx集群架构文档

Bertha 。 2021-10-31 16:34 286阅读 0赞

1.准备两台机器

A机器：192.168.232.132

B机器：192.168.232.131

A级器作为master，B机器作为backup

2.两台机器都安装：keepalived

A机器
    [root@aaa-01 ~]# yum install -y keepalived
    B机器
    [root@bbb-01 ~]# yum install -y keepalived

3.两台机器上都安装nginx

若是A、B机器没有装nginx服务，可以直接 yum安装

因为我A机器上已经源码包安装编译过nginx了所以就不用再安装了

B机器安装完之后启动nginx

[root@bbb-01 ~]# yum install -y nginx
    [root@bbb-01 ~]# service nginx start
    Redirecting to /bin/systemctl start nginx.service
    [root@bbb-01 ~]# ps aux|grep nginx
    root     16687  0.0  0.0  46364   964 ?        Ss   11:51   0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf
    nginx    16688  0.0  0.1  46764  1924 ?        S    11:51   0:00 nginx: worker process
    root     16690  0.0  0.0 112676   980 pts/0    R+   11:51   0:00 grep --color=auto nginx

注意：有时直接yum安装不了，需要安装yum扩展源：yum install -y epel-release

**下面是在A机器上操作的**

1.更改A机器上的更改keepalived配置文件

默认的配置文件路径在/etc/keepalived/keepalived.conf

清空文件内容

> /etc/keepalived/keepalived.conf

编辑配置文件

vim /etc/keepalived/keepalived.conf

添加加以下内容：

global_defs {
       notification_email {
         aming@aminglinux.com
       }
       notification_email_from root@aminglinux.com
       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 MASTER
        interface ens33
        virtual_router_id 51
        priority 100
        advert_int 1
        authentication {
            auth_type PASS
            auth_pass aminglinux>com
        }
        virtual_ipaddress {
            192.168.232.100
        }
        track_script {
            chk_nginx
        }
    }

这里需要注意的是："virtual\_ipaddress"也就是所谓的vip我们设置为192.168.232.100

2.定义监控脚本

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

编辑配置文件：

vim /usr/local/sbin/check_ng.sh

增加以下内容：

#!/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

3.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@aaa-01 ~]# chmod 755 /usr/local/sbin/check_ng.sh

4.启动keepalived服务，并查看是否启动成功

[root@aaa-01 ~]# systemctl start keepalived
    [root@aaa-01 ~]# ps aux |grep keepalived
    root     34653  0.0  0.1 118652  1400 ?        Ss   12:16   0:00 /usr/sbin/keepalived -D
    root     34654  0.0  0.2 122852  2392 ?        S    12:16   0:00 /usr/sbin/keepalived -D
    root     34655  0.0  0.2 122852  2448 ?        S    12:16   0:00 /usr/sbin/keepalived -D
    root     34661  0.0  0.0 112720   988 pts/1    S+   12:16   0:00 grep --color=auto keepalived

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查看防火墙
    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

5.这时停止nginx服务

/etc/init.d/nginx stop

再来查看nginx服务进程，会看到自动加载了

[root@aaa-01 ~]# /etc/init.d/nginx stop
    Stopping nginx (via systemctl):                            [  确定  ]
    [root@aaa-01 ~]# ps aux |grep nginx
    root     34813  0.0  0.0  20548   628 ?        Ss   12:17   0:00 nginx: master process /usr/local/nginx/sbin/nginx -c /usr/local/nginx/conf/nginx.conf
    nobody   34817  0.0  0.3  22992  3216 ?        S    12:17   0:00 nginx: worker process
    nobody   34818  0.0  0.3  22992  3216 ?        S    12:17   0:00 nginx: worker process
    root     34832  0.0  0.0 112720   984 pts/1    R+   12:17   0:00 grep --color=auto nginx

6.查看ip地址，使用 ip add 命令,可以查看到vip192.168.232.100

[root@aaa-01 ~]# ip add
    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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:c2:05:5a brd ff:ff:ff:ff:ff:ff
        inet 192.168.232.132/24 brd 192.168.232.255 scope global dynamic ens33
           valid_lft 1559sec preferred_lft 1559sec
        inet 192.168.232.100/32 scope global ens33
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fec2:55a/64 scope link 
           valid_lft forever preferred_lft forever

**以下是B机器上的配置**

1.自定义B机器keepalived配置文件，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

配置文件路径：/etc/keepalived/keepalived.conf
    清空：> /etc/keepalived/keepalived.conf

编辑配置文件：

[root@bbb-01 ~]# vim /etc/keepalived/keepalived.conf

增加以下内容：

global_defs {
       notification_email {
         aming@aminglinux.com
       }
       notification_email_from root@aminglinux.com
       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192.168.232.100
        }
        track_script {
            chk_nginx
        }
    }

2.定义监控脚本，路径再keepalived里面已定义过

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

增加以下内容：

#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

3.改动脚本的权限，设置为755权限

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

4.启动keepalived服务：

[root@bbb-01 ~]# systemctl start keepalived
    [root@bbb-01 ~]# ps aux |grep keep
    root     19134  0.0  0.1 118608  1384 ?        Ss   12:33   0:00 /usr/sbin/keepalived -D
    root     19135  0.0  0.2 122804  2384 ?        S    12:33   0:00 /usr/sbin/keepalived -D
    root     19136  0.0  0.2 122804  2424 ?        S    12:33   0:00 /usr/sbin/keepalived -D
    root     19143  0.0  0.0 112676   984 pts/0    R+   12:33   0:00 grep --color=auto keep

**区分主和从上的nginx**

1.**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@aaa-01]# 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;
    }

2.索引页：

[root@aaa-01~]# cat /data/wwwroot/default/index.html 
    This is the default sete.
    [root@aaa-01~]# vim /data/wwwroot/default/index.html   #增加内容 
    master This is the default sete.

3.用网页查看

![image.png][]

**B机器**是yum安装的nginx

默认的索引页在 /usr/share/nginx/html/index.html

\[root@bbb-01 ~\]\# vim /usr/share/nginx/html/index.html \#增加内容

backup backup.

网页查看

![image.png][image.png 1]

访问192.168.132.100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

![image.png][image.png 2]

测试高可用

1.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

查看A机器上的VIP被已经释放掉了

[root@aaa-01 ~]# systemctl start keepalived
    [root@aaa-01 ~]# ip add
    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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:c2:05:5a brd ff:ff:ff:ff:ff:ff
        inet 192.168.232.132/24 brd 192.168.232.255 scope global dynamic ens33
           valid_lft 1532sec preferred_lft 1532sec
        inet6 fe80::20c:29ff:fec2:55a/64 scope link 
           valid_lft forever preferred_lft forever

2.查看backup机器（即B机器）发现它在监听VIP

[root@bbb-01 ~]# ip add
    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: ens33: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc pfifo_fast state UP qlen 1000
        link/ether 00:0c:29:fb:fc:6f brd ff:ff:ff:ff:ff:ff
        inet 192.168.232.131/24 brd 192.168.232.255 scope global dynamic ens33
           valid_lft 1179sec preferred_lft 1179sec
        inet 192.168.232.100/32 scope global ens33
           valid_lft forever preferred_lft forever
        inet6 fe80::20c:29ff:fefb:fc6f/64 scope link 
           valid_lft forever preferred_lft forever

3.浏览器访问vip，会看到已经变成backup机器上的了

![image.png][image.png 3]

这证明成功了，当A机器出现问题B机器就顶了上去

[image.png]: /images/20211031/6c87cef6d8734b018dad370a83374749.png
[image.png 1]: /images/20211031/ca29d18af9514cfda7f820c9498d154f.png
[image.png 2]: /images/20211031/30628fbe085e44e0a7e15fa920bac045.png
[image.png 3]: /images/20211031/aa31efab0dcf4d8294c72325c43f4e7c.png