首页 > 技术文章 > 在Rancher中添加Mysql-Master-Slave,使得django数据库读写分离。

BigStupid 2018-09-30 16:43 原文

1.拉取mysql镜像

 docker pull deoj/mysql:v1 

2.(1)在Rancher中创建Master容器:

 

添加容器拉去本地镜像,以及开放端口:

 

 

添加外部配置文件,以及数据持久化:

 

 

(2)在Rancher中创建Slave-1、Slave-2容器:

添加容器拉去本地镜像,以及开放端口:

  

 

添加外部配置文件,以及数据持久化:

 

 

如图:

 

 3.(1)进入master容器中:

(2) show databases; #查看数据库test有没有创建成功 

  

红色标记证明创建成功,然后执行如下代码来查看master状态;

show master status;

其中红色标记的参数需要在配置文件中用到先记录下来。

下面是master的配置文件:

[mysqld]
server-id       = 2
port            = 3302
binlog-ignore-db = mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
#default-storage-engine = InnoDB
log-bin         = mysql-bin-master
binlog_cache_size = 1M
binlog_format = mixed
expire_logs_days = 7
#log-error      = /var/log/mysql/error.log
# By default we only accept connections from localhost
bind-address    = 0.0.0.0
#bind-address   = 192.168.1.126
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
character-set-server=utf8mb4
collation-server=utf8mb4_unicode_ci

replicate-wild-ignore-table = mysql.%
sync_binlog                 = 1

*因为我的图片是第二天截取的,docker重启过,导致参数不一致,在配置时填写当前状态的参数即可。

(3)进入slave容器中:

change master to master_host='192.168.1.126', master_user='root', master_password='1', master_port=3302, master_log_file='mysql-bin-master.000006', master_log_pos=126891, master_connect_retry=30;

执行上面的代码来添加master到slave中。

start slave;

开启slave模式;

show slave status \G;

查看slave状态,是否添加成功:

截图中,红色框框包含了master的一些参数,橘黄色框框yes,yes表示slave运行状态(前提是执行了slave start;),如果为no,no则slave没有运行。

下面是slave的配置文件:

[mysqld]
server-id       = 4
port            = 3304

binlog-ignore-db= mysql
pid-file        = /var/run/mysqld/mysqld.pid
socket          = /var/run/mysqld/mysqld.sock
datadir         = /var/lib/mysql
default-storage-engine  = InnoDB
log-bin         = mysql-bin-slave-2
#log-error      = /var/log/mysql/error.log
# By default we only accept connections from localhost
bind-address   = 0.0.0.0
# Disabling symbolic-links is recommended to prevent assorted security risks
symbolic-links=0
character-set-server=utf8mb4
collation-server=utf8mb4_unicode_ci
binlog_cache_size = 1M
binlog_format     = mixed
expire_logs_days  = 7
slave_skip_errors = 1062
relay_log         = mysql-relay-bin-2
log_slave_updates = 1
read_only = 1

 

 4.(1)进入django项目settings.py中,添加master-slave数据库(我添加了2个slave):

  

DATABASES = {
    
    'default': {
         'ENGINE': 'django.db.backends.mysql',
         'NAME': 'test',
         'USER': 'root',
         'PASSWORD': '1',
         'HOST': '192.168.1.126',
         'PORT': '3302',
    },
    'slave-1': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'test',
        'USER': 'root',
        'PASSWORD': '1',
        'HOST': '192.168.1.126',
        'PORT': '3303',
    },
    'slave-2': {
        'ENGINE': 'django.db.backends.mysql',
        'NAME': 'test',
        'USER': 'root',
        'PASSWORD': '1',
        'HOST': '192.168.1.126',
        'PORT': '3304',
    },
}
DATABASE_ROUTERS = ['ergaleng.myrouter.Router',]
 

(2)在settings.py同级目录下创建myrouter.py文件(需要将该文件引入到settings.py不然不能用里面的类):

class Router(object):
    def db_for_read(self, model, **hints):
        """
        读取随即一个数据库
        :param model:
        :param hints:
        :return:
        """
        try:
            import random
            print("into slave")
            return random.choice(['slave-1','slave-2'])
        except:
            return 'default'

    def db_for_write(self, model, **hints):
        """
        写入时选择主数据库
        :param model:
        :param hints:
        :return:
        """
        print("into default")
        return 'default'

    def allow_relation(self, obj1, obj2, **hints):
        return None

    def allow_migrate(self, db, app_label, model=None, **hints):
        return None

*其中,代码逻辑就是将读操作与写操作分离,当涉及到读操作时,数据库在slave-1和slave-2中随机选择,当涉及写操作时,数据库选择default (master)。

(3)进入django容器中,进行数据库表创建:

python manage.py makemigrations
python manage.py migrate   #默认default

因为配置了数据库主从复制,所以在master中创建的数据会自动同步到分数据库中。

执行 python manage.py shell 进入shell中,

root@python-2:/# cd data/
root@python-2:/data# python manage.py shell
Python 3.6.6 (default, Sep  5 2018, 03:40:52)
[GCC 6.3.0 20170516] on linux
Type "help", "copyright", "credits" or "license" for more information.
(InteractiveConsole)
>>> from flow import models
>>> models.User.objects.create(username="hello")
into default
<User: hello>
>>> models.User.objects.all()[0]
into slave
<User: hehe>
>>>

如上结果,说明基于Docker 的 Mysql主从架构已经设置完成。

 (4)用 nginx+vue+django-restframework +uwsgi进行实际项目下的测试结果如下,橘黄色为读操作(读操作:查操作),红色框框为写操作(写操作:创建、更新、删除操作):

 

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