docker简易实现数据库的双机热备

落日映苍穹つ 2022-05-21 08:16 110阅读 0赞

写在前面：为什么要采用双机热备？虽然我们在数据库进行了负载均衡，但单节点Haproxy不具备高可用，一旦Haroxy节点故障，应用程序将无法访问，故必须要有冗余设计，使用keepalived进行双机热备。注：在阅读此文之前，最好请先阅读《docker简易搭建MySQL集群的负载均衡》[https://blog.csdn.net/belonghuang157405/article/details/80883342][https_blog.csdn.net_belonghuang157405_article_details_80883342]

最终想实现的架构效果图：  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JlbG9uZ2h1YW5nMTU3NDA1_size_16_color_FFFFFF_t_70]

## 第一步 Haproxy容器安装Keepalived ##

Keepalived必须要在Haproxy所在的容器之内。故首先进入Haproxy容器内，执行如下命令：

docker exec -it haproxy1 bash

在进入haproxy1容器后，执行如下命令，安装keepalived：

apt-get update
    apt-get install keepalived

*注：由于Haproxy镜像是基于Ubuntu创建出来的，故使用apt-get 而不是yum。  
如果读者在运行apt-get更新较慢，或者发现安装keepalived出现‘Unable to locate package’错误，是由于更新的数据在国外，可百度apt-get加速方式，也可参考附录提供的方式。*

## 第二步 编写Keepalived配置文件 ##

Keepalived的配置文件位置： /etc/keepalived/keepalived.conf

apt-get install vim
    vim /etc/keepalived/keepalived.conf

将如下文件内容，复制进文件中：

vrrp_instance  VI_1 {
        state  MASTER
        interface  eth0
        virtual_router_id  51
        priority  100
        advert_int  1
        authentication {
            auth_type  PASS
            auth_pass  123456
        }
        virtual_ipaddress {
            172.18.0.201
        }
    }

## 第三步 启动keepalived ##

在keepalived容器中，执行如下命令：

service keepalived start

## 第四步 验证是否成功启动keepalived ##

在宿主机中，ping keepalived设置的虚拟ip（virtual\_ipaddress ），执行如下命令：

ping 172.18.0.201

检查是否能ping通。结果如下：

[root@localhost ~]# ping 172.18.0.201
    PING 172.18.0.201 (172.18.0.201) 56(84) bytes of data.
    64 bytes from 172.18.0.201: icmp_seq=1 ttl=64 time=0.110 ms
    64 bytes from 172.18.0.201: icmp_seq=2 ttl=64 time=0.140 ms
    64 bytes from 172.18.0.201: icmp_seq=3 ttl=64 time=0.080 ms

## 第五步 创建haproxy2容器,并配置与haproxy1相同的环境 ##

创建与haproxy1一样环境的haproxy2容器，安装keepalived实现争抢虚拟ip，实现双机热备。 执行如下命令：

##### 1.创建第2个Haproxy负载均衡服务器haproxy2 #####

docker run -it -d -p 4003:8888 -p 4004:3306 -v /home/soft/haproxy:/usr/local/etc/haproxy --name haproxy2 --privileged --net=net1 haproxy

##### 2.进入haproxy2容器中，并启动Haproxy #####

docker exec -it harpoxy2 bash
       haproxy -f /usr/local/etc/haproxy/haproxy.cfg

##### 3.在haproxy2容器中，安装keepalived并编写该配置文件 #####

#更新软件包
        apt-get update
        #安装VIM
        apt-get install vim
        #安装Keepalived
        apt-get install keepalived
        #编辑Keepalived配置文件
        vim /etc/keepalived/keepalived.conf

配置文件内容如下：

vrrp_instance  VI_1 { 
            state  MASTER
            interface  eth0
            virtual_router_id  51
            priority  100
            advert_int  1
            authentication { 
                auth_type  PASS
                auth_pass  123456
            }
            virtual_ipaddress { 
                172.18.0.201
            }
        }

##### 4.启动keepalived，并测试验证 #####

#启动Keepalived
        service keepalived start
        #宿主机停止haproxy1容器
        docker pause haproxy1
        #宿主机执行ping命令
        ping 172.18.0.201
        #宿主机恢复haproxy1容器
        docker unpause haproxy1

## 第六步 在宿主机上安装keepalived，实现双机热备 ##

在宿主机安装keepalived，并配置该配置文件。

##### 1.在centos窗口执行如下命令,安装keepalived： #####

yum -y install keepalived

##### 2.编写keepalived.conf配置文件，执行如下命令： #####

vi /etc/keepalived/keepalived.conf

删除原先内容，将内容如下粘贴进去：

vrrp_instance VI_1 {
            state MASTER
            interface eth0
            virtual_router_id 51
            priority 100
            advert_int 1
            authentication {
                auth_type PASS
                auth_pass 1111
            }
            virtual_ipaddress {
               	192.168.9.144
            }
        }
    
        virtual_server 192.168.9.144 8888 {
            delay_loop 3
            lb_algo rr
            lb_kind NAT
            persistence_timeout 50
            protocol TCP
    
            real_server 172.18.0.201 8888 {
                weight 1
            }
        }
    
        virtual_server 192.168.9.144 3306 {
            delay_loop 3
            lb_algo rr
            lb_kind NAT
            persistence_timeout 50
            protocol TCP
    
            real_server 172.18.0.201 3306 {
                weight 1
            }
        }

*注：内容中192.168.9.144 该ip是宿主虚拟ip，读者可自定义请自行更改。 172.18.0.201 是容器keepalived设置争抢的虚拟ip，8888是监控界面端口 3306是数据库端口*

##### 3.启动keepalived，执行如下命令： #####

service keepalived start

##### 5.验证keepalived是否成功。 #####

1.数据库验证  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JlbG9uZ2h1YW5nMTU3NDA1_size_16_color_FFFFFF_t_70 1]  
2.haproxy监控界面验证  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2JlbG9uZ2h1YW5nMTU3NDA1_size_16_color_FFFFFF_t_70 2]  
*注：宿主机定义的虚拟ip为192.168.9.144，读者自行更改*

### 附录： ###

**1.Ubuntu将apt-get修改成163镜像的源**

第一步 修改sources.list配置文件

vim /etc/apt/sources.list

*注：如果没有vim，请预先安装vim，执行如下命令：*

apt-get install vim

删除sources.list文件内容，将下方内容粘贴进去，sources.list内容如下：

deb http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse 
    deb-src http://mirrors.163.com/ubuntu/ precise main universe restricted multiverse 
    deb http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted 
    deb-src http://mirrors.163.com/ubuntu/ precise-security universe main multiverse restricted 
    deb http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted 
    deb http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted 
    deb-src http://mirrors.163.com/ubuntu/ precise-proposed universe main multiverse restricted 
    deb http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted 
    deb-src http://mirrors.163.com/ubuntu/ precise-backports universe main multiverse restricted 
    deb-src http://mirrors.163.com/ubuntu/ precise-updates universe main multiverse restricted

粘贴完后，保存退出。  
第二步 apt清除原先的配置并更新，执行如下命令：

apt-get clean
    apt-get update

**2.当Ubuntu容器apt-get update执行后 报出如下错误：**

0% [Connecting to deb.debian.org] [Connecting to security.debian.org]
    0% [Connecting to deb.debian.org] [Connecting to security.debian.org]
    Err:1 http://security.debian.org/debian-security stretch/updates InRelease
      Temporary failure resolving 'security.debian.org'
    Err:2 http://deb.debian.org/debian stretch InRelease                 
      Temporary failure resolving 'deb.debian.org'
    Err:3 http://deb.debian.org/debian stretch-updates InRelease
      Temporary failure resolving 'deb.debian.org'
    Reading package lists... Done    
    W: Failed to fetch http://deb.debian.org/debian/dists/stretch/InRelease  Temporary failure resolving 'deb.debian.org'
    W: Failed to fetch http://security.debian.org/debian-security/dists/stretch/updates/InRelease  Temporary failure resolving 'security.debian.org'
    W: Failed to fetch http://deb.debian.org/debian/dists/stretch-updates/InRelease  Temporary failure resolving 'deb.debian.org'
    W: Some index files failed to download. They have been ignored, or old ones used instead.

请查看自己的docker是否加入了镜像加速。方法如下：  
在宿主机 修改docker的damemon.json文件，如果不存在请新建，将如下内容粘贴保存：

{ 
       "registry-mirrors": ["https://vcmrfdsm.mirror.aliyuncs.com"]
    }

保存成功后，请重启docker服务(在执行此命令前，请先保存好数据库数据)，执行如下命令：

service docker restart

如果意外重启了，发现node1，node2，node3，node4容器节点节无法重启启动，请将先删除这四个容器，并删除v1，v2，v3，v4四个docker卷。而后参考《docker简易搭建MySQL集群》重新创建这四个节点容器。

[https_blog.csdn.net_belonghuang157405_article_details_80883342]: https://blog.csdn.net/belonghuang157405/article/details/80883342
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