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keepalived+nginx实现高可用实战(nginx和keepalived如何搭建高可用集群)

xnh888 2024-10-02 03:19:58 技术教程 15 ℃ 0 评论

Keepalived的作用是检测服务器的状态,如果有一台web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,这些工作全部自动完成,不需要人工干涉,需要人工做的只是修复故障的服务器。

下面这里我们就用keepalived+nginx来测试下。

一、环境

这里准备两台机器,一台是主一台是备

#nginx11
192.168.192.11 MASTER
#nginx02
192.168.192.12 BACKUP
然后keepalive用的虚拟ip是
192.168.192.13

我们的目的就是通过访问192.168.192.13,会去到192.168.192.11,当192.168.192.11挂了后就会去到192.168.192.12

nginx环境搭建可以参考Nginx实战

虚拟机的安装和克隆可以参考一个Java程序员从事网站开发要了解和掌握的基本技术
中的Linux服务器准备

二、keepalived+nginx实现高可用实战

1、官网下载

https://www.keepalived.org/download.html
这里下载Release版本:keepalived-2.0.6.tar.gz

注:开始我用keepalived-2.1.0.tar.gz版本,报如下错误,找不到解决办法,就只能换低一点的版本了,望知道的说下!

make[1]: Entering directory `/usr/local/keepalived-2.1.0/keepalived'
Making all in core
make[2]: Entering directory `/usr/local/keepalived-2.1.0/keepalived/core'
  CC       namespaces.o
In file included from /usr/include/netlink/handlers.h:19:0,
                 from /usr/include/netlink/socket.h:16,
                 from namespaces.c:171:
/usr/include/netlink/netlink-kernel.h:193:2: error: unknown type name ‘__u32’
  __u32 group;
  ^
make[2]: *** [namespaces.o] Error 1
make[2]: Leaving directory `/usr/local/keepalived-2.1.0/keepalived/core'
make[1]: *** [all-recursive] Error 1
make[1]: Leaving directory `/usr/local/keepalived-2.1.0/keepalived'
make: *** [all-recursive] Error 1

2、解压

上传到/usr/local目录下面解压

tar -zxvf keepalived-2.1.0.tar.gz

3、configure配置

cd /usr/local/keepalived-2.1.0
./configure --prefix=/usr/local/keepalived --sysconf=/etc
  • prefix:keepalived安装的位置
  • sysconf:keepalived核心配置文件所在位置,固定位置,改成其他位置则keepalived启动不了,/var/log/messages中会报错

执行完后会有警告

*** WARNING - this build will not support IPVS with IPv6. Please install libnl/libnl-3 dev libraries to support IPv6 with IPVS.

安装 libnl/libnl-3 依赖

yum -y install libnl libnl-devel

重新执行

./configure --prefix=/usr/local/keepalived --sysconf=/etc

发现没有警告了。

4、安装

make && make install

5、Keepalived 配置

cd /etc/keepalived
[root@localhost keepalived]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 group default qlen 1000
    link/ether 00:50:56:36:1a:25 brd ff:ff:ff:ff:ff:ff
    inet 192.168.192.11/24 brd 192.168.192.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::a4ce:6997:d06a:d685/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever

我们用的网卡是ens33

修改配置文件,假设我们这里的VIP为192.168.192.13,并且这台节点为MASTER,配置文件为

global_defs {
   # 路由id:当前安装keepalived的节点主机标识符,保证全局唯一
   router_id keep_11
}

vrrp_instance VI_1 {
    # 表示状态是MASTER主机还是备用机BACKUP
    state MASTER
    # 该实例绑定的网卡名称
    interface ens33
    # 保证主备节点一致即可
    virtual_router_id 13
    # 权重,master权重一般高于backup,如果有多个,那就是选举,谁的权重高,谁就当选
    priority 100
    # 主备之间同步检查时间间隔,单位秒
    advert_int 2
    # 认证权限密码,防止非法节点进入
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    # 虚拟出来的ip,可以有多个(vip)
    virtual_ipaddress {
        192.168.192.13
    }
}

然后我们克隆一台机器,修改另一台机器的配置文件为BACKUP

global_defs {
   # 路由id:当前安装keepalived的节点主机标识符,保证全局唯一
   router_id keep_12
}

vrrp_instance VI_1 {
    # 表示状态是MASTER主机还是备用机BACKUP
    state BACKUP
    # 该实例绑定的网卡名称
    interface ens33
    # 保证主备节点一致即可
    virtual_router_id 13
    # 权重,master权重一般高于backup,如果有多个,那就是选举,谁的权重高,谁就当选
    priority 80
    # 主备之间同步检查时间间隔,单位秒
    advert_int 2
    # 认证权限密码,防止非法节点进入
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    # 虚拟出来的ip,可以有多个(vip)
    virtual_ipaddress {
        192.168.192.13
    }
}

6、启动MASTER

cd /usr/local/keepalived/sbin
./keepalived
[root@localhost sbin]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 group default qlen 1000
    link/ether 00:50:56:36:1a:25 brd ff:ff:ff:ff:ff:ff
    inet 192.168.192.11/24 brd 192.168.192.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.192.13/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::a4ce:6997:d06a:d685/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@localhost sbin]#

可以看到ens33多了一个192.168.192.13

7、启动BACKUP

cd /usr/local/keepalived/sbin
./keepalived
[root@localhost sbin]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 group default qlen 1000
    link/ether 00:50:56:3c:89:c3 brd ff:ff:ff:ff:ff:ff
    inet 192.168.192.12/24 brd 192.168.192.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet 192.168.192.13/32 scope global ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::a4ce:6997:d06a:d685/64 scope link tentative noprefixroute dadfailed 
       valid_lft forever preferred_lft forever
    inet6 fe80::137c:d64d:c120:b79e/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@localhost sbin]#

可以看到ens33也多了一个192.168.192.13

8、访问

我们访问192.168.192.13,会发现

Welcome to nginx MASTER 11!

页面显示这个,表面目前是在MASTER的

9、模拟服务中断
正常我们定义某个节点有故障了,就是keepalived的进程都不在了,所以我们可以在MASTER执行

killall keepalived

要是没有这命令可以先安装

yum -y  install psmisc

kill后我们发现

[root@localhost html]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
    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 group default qlen 1000
    link/ether 00:50:56:36:1a:25 brd ff:ff:ff:ff:ff:ff
    inet 192.168.192.11/24 brd 192.168.192.255 scope global noprefixroute ens33
       valid_lft forever preferred_lft forever
    inet6 fe80::a4ce:6997:d06a:d685/64 scope link noprefixroute 
       valid_lft forever preferred_lft forever
[root@localhost html]#

192.168.192.13就不见了。

再访问192.168.192.13

Welcome to nginx BACKUP 12!

成功切到了备用机!

我们再启动MASTER的keepalived后,再访问192.168.192.13

Welcome to nginx MASTER 11!

10、那我们监控的好像都是keepalived?不是nginx啊?

正常我们都会在keepalived配置中配置一个检查脚本,定时检查nginx进程是否存在,若是不存在则同时killall keepalived,这样就相当于监控了nginx.

11、keepalived相关命令

# 启动keepalived
systemctl start keepalived
# 停止keepalived
systemctl stop keepalived
# 重启keepalived
systemctl restart keepalived

12、Keepalived 配置 Nginx 自动重启

1、增加Nginx重启检测脚本

vim /etc/keepalived/check_nginx_alive_or_not.sh
#!/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
    /usr/local/nginx/sbin/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

增加运行权限

chmod +x /etc/keepalived/check_nginx_alive_or_not.sh

2、在 keepalived.conf 配置定时监听 nginx 状态脚本

vrrp_script check_nginx_alive {
    script "/etc/keepalived/check_nginx_alive_or_not.sh"
    interval 2 # 每隔两秒运行上一行脚本
    weight 10 # 如果脚本运行成功,则升级权重+10
    # weight -10 # 如果脚本运行失败,则升级权重-10
}

3、在vrrp_instance中新增监控的脚本

track_script {
    check_nginx_alive   # 追踪 nginx 脚本
}

4、重启Keepalived使得配置文件生效

systemctl restart keepalived

5、测试Nginx是否会自动重启

cd /usr/local/nginx/sbin
#停止
./nginx -s stop
#查看进程是否存在
ps -ef|grep nginx

这里我们配置脚本是每隔两秒运行一次,所以手速要快,当然如果你手速不快的话,可以把运行时间加长,就会看到效果。我们已停止nginx,马上查进程是查不到的,过一会再查又有了。

6、加上监控的配置文件

global_defs {
   # 路由id:当前安装keepalived的节点主机标识符,保证全局唯一
   router_id keep_11
}
vrrp_script check_nginx_alive {
    script "/etc/keepalived/check_nginx_alive_or_not.sh"
    interval 2 # 每隔两秒运行上一行脚本
    weight 10 # 如果脚本运行成功,则升级权重+10
    # weight -10 # 如果脚本运行失败,则升级权重-10
}
vrrp_instance VI_1 {
    # 表示状态是MASTER主机还是备用机BACKUP
    state MASTER
    # 该实例绑定的网卡名称
    interface ens33
    # 保证主备节点一致即可
    virtual_router_id 13
    # 权重,master权重一般高于backup,如果有多个,那就是选举,谁的权重高,谁就当选
    priority 100
    # 主备之间同步检查时间间隔,单位秒
    advert_int 2
    # 认证权限密码,防止非法节点进入
    authentication {
        auth_type PASS
        auth_pass 1111
    }
    # 虚拟出来的ip,可以有多个(vip)
    virtual_ipaddress {
        192.168.192.13
    }
    track_script {
        check_nginx_alive   # 追踪 nginx 脚本
    }
}

上面出现了脑裂问题,已经解决,可看本集合下一篇~

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