Centos7怎么配置Mysql多主一从

业务场景：

公司几个主要的业务已经独立，放在不同的数据库服务器上面，但是有一个业务又需要关联多个业务库进行联合查询统计。这时候就需要将不同的业务库数据同步到一台从库进行统计。根据mysql主从同步原理使用多从一主的方案解决。主库使用innodb引擎，从库开启多实例使用myisam引擎并将多个实例的数据同步到同一个目录，并通过flush tables 在一个实例里面访问其他实例的数据。

解决思路：

1、主数据库使用innodb引擎，并设置sql_mode为 no_auto_create_user
2、从库开启多实例，将多个主库里面的数据通过主从复制同步到同一个数据目录。从库的每个实例对应一个主库。多个实例使用同一个数据目录。
3、从库使用myisam引擎，关闭从库默认的innodb引擎,myisam引擎可以访问同一个数据目录里面其他实例的表。
4、从库的每个实例需要执行flush tables 才能看到其他实例表的数据变化，可以设置crontab任务计划每分钟在第一个实例刷新表，以便程序连接的默认实例能看到表的实时变化。
5、设置主库和从库的sql_mode都为no_auto_create_user，只有这样主库的innodb引擎的sql同步到从库的时候才能执行成功。

方案架构图：

环境说明：

主库-1：192.168.1.1
主库-2：192.168.1.2
从库-3：192.168.1.3
从库-3：192.168.1.4
从库-3：192.168.1.5

实现步骤：（mysql安装步骤这里不在描述）

1、主数据库配置文件，多个主库配置文件除了server-id不能一样其他都一样。

[root@masterdb01 ~]#cat /etc/my.cnf
[client]
port= 3306
socket= /tmp/mysql.sock
[mysqld]
port = 3306
basedir = /usr/local/mysql
datadir = /data/mysql
character-set-server = utf8mb4
default-storage-engine = innodb
socket = /tmp/mysql.sock
skip-name-resolv = 1
open_files_limit = 65535 
back_log = 103
max_connections = 512
max_connect_errors = 100000
table_open_cache = 2048
tmp-table-size  = 32m
max-heap-table-size = 32m
#query-cache-type = 0
query-cache-size = 0
external-locking = false
max_allowed_packet = 32m
sort_buffer_size = 2m
join_buffer_size = 2m
thread_cache_size = 51
query_cache_size = 32m
tmp_table_size = 96m
max_heap_table_size = 96m
query_cache_type=1
log-error=/data/logs/mysqld.log
slow_query_log = 1
slow_query_log_file = /data/logs/slow.log
long_query_time = 0.1
# binary logging #
server-id = 1
log-bin     = /data/binlog/mysql-bin
log-bin-index  =/data/binlog/mysql-bin.index
expire-logs-days = 14
sync_binlog = 1
binlog_cache_size = 4m
max_binlog_cache_size = 8m
max_binlog_size = 1024m
log_slave_updates
#binlog_format = row 
binlog_format = mixed  //这里使用的混合模式复制
relay_log_recovery = 1
#不需要同步的表
replicate-wild-ignore-table=mydb.sp_counter
#不需要同步的库
replicate-ignore-db = mysql,information_schema,performance_schema
key_buffer_size = 32m
read_buffer_size = 1m
read_rnd_buffer_size = 16m
bulk_insert_buffer_size = 64m
myisam_sort_buffer_size = 128m
myisam_max_sort_file_size = 10g
myisam_repair_threads = 1
myisam_recover
transaction_isolation = repeatable-read
innodb_additional_mem_pool_size = 16m
innodb_buffer_pool_size = 5734m
innodb_buffer_pool_load_at_startup = 1
innodb_buffer_pool_dump_at_shutdown = 1
innodb_data_file_path = ibdata1:1024m:autoextend
innodb_flush_log_at_trx_commit = 2
innodb_log_buffer_size = 32m
innodb_log_file_size = 2g
innodb_log_files_in_group = 2
innodb_io_capacity = 4000
innodb_io_capacity_max = 8000
innodb_max_dirty_pages_pct = 50
innodb_flush_method = o_direct
innodb_file_format = barracuda
innodb_file_format_max = barracuda
innodb_lock_wait_timeout = 10
innodb_rollback_on_timeout = 1
innodb_print_all_deadlocks = 1
innodb_file_per_table = 1
innodb_locks_unsafe_for_binlog = 0
[mysqldump]
quick
max_allowed_packet = 32m

2、从库配置文件。多个从库配置文件除了server-id不能一样其他都一样。

[root@slavedb01 ~]# cat /etc/my.cnf
[client]
port= 3306
socket= /tmp/mysql.sock
[mysqld_multi]
# 指定相关命令的路径
mysqld   = /usr/local/mysql/bin/mysqld_safe
mysqladmin = /usr/local/mysql/bin/mysqladmin
##复制主库1的数据##
[mysqld2]
port = 3306
basedir = /usr/local/mysql
datadir = /data/mysql
character-set-server = utf8mb4
#指定实例1的sock文件和pid文件
socket = /tmp/mysql.sock
pid-file=/data/mysql/mysql.pid
skip-name-resolv = 1
open_files_limit = 65535 
back_log = 103
max_connections = 512
max_connect_errors = 100000
table_open_cache = 2048
tmp-table-size  = 32m
max-heap-table-size = 32m
query-cache-size = 0
external-locking = false
max_allowed_packet = 32m
sort_buffer_size = 2m
join_buffer_size = 2m
thread_cache_size = 51
query_cache_size = 32m
tmp_table_size = 96m
max_heap_table_size = 96m
query_cache_type=1
#指定第一个实例的错误日志和慢查询日志路径
log-error=/data/logs/mysqld.log
slow_query_log = 1
slow_query_log_file = /data/logs/slow.log
long_query_time = 0.1
# binary logging#
# 指定实例1的binlog和relaylog路径为/data/binlog目录
# 每个从库和每个实例的server_id不能一样。
server-id = 2
log-bin     = /data/binlog/mysql-bin
log-bin-index  =/data/binlog/mysql-bin.index
relay_log = /data/binlog/mysql-relay-bin
relay_log_index = /data/binlog/mysql-relay.index
master-info-file = /data/mysql/master.info
relay_log_info_file = /data/mysql/relay-log.info
read_only = 1
expire-logs-days = 14
sync_binlog = 1
#需要同步的库，如果不设置，默认同步所有库。
#replicate-do-db = xxx
#不需要同步的表
replicate-wild-ignore-table=mydb.sp_counter
#不需要同步的库
replicate-ignore-db = mysql,information_schema,performance_schema
binlog_cache_size = 4m
max_binlog_cache_size = 8m
max_binlog_size = 1024m
log_slave_updates =1
#binlog_format = row 
binlog_format = mixed
relay_log_recovery = 1
key_buffer_size = 32m
read_buffer_size = 1m
read_rnd_buffer_size = 16m
bulk_insert_buffer_size = 64m
myisam_sort_buffer_size = 128m
myisam_max_sort_file_size = 10g
myisam_repair_threads = 1
myisam_recover
#设置默认引擎为myisam，下面这些参数一定要加上。
default-storage-engine=myisam
default-tmp-storage-engine=myisam
#关闭innodb引擎
skip-innodb
innodb = off
disable-innodb
#设置sql_mode模式为no_auto_create_user
sql_mode = no_auto_create_user
#关闭innodb引擎
loose-skip-innodb
loose-innodb-trx=0 
loose-innodb-locks=0 
loose-innodb-lock-waits=0 
loose-innodb-cmp=0 
loose-innodb-cmp-per-index=0
loose-innodb-cmp-per-index-reset=0
loose-innodb-cmp-reset=0 
loose-innodb-cmpmem=0 
loose-innodb-cmpmem-reset=0 
loose-innodb-buffer-page=0 
loose-innodb-buffer-page-lru=0 
loose-innodb-buffer-pool-stats=0 
loose-innodb-metrics=0 
loose-innodb-ft-default-stopword=0 
loose-innodb-ft-inserted=0 
loose-innodb-ft-deleted=0 
loose-innodb-ft-being-deleted=0 
loose-innodb-ft-config=0 
loose-innodb-ft-index-cache=0 
loose-innodb-ft-index-table=0 
loose-innodb-sys-tables=0 
loose-innodb-sys-tablestats=0 
loose-innodb-sys-indexes=0 
loose-innodb-sys-columns=0 
loose-innodb-sys-fields=0 
loose-innodb-sys-foreign=0 
loose-innodb-sys-foreign-cols=0
 
 
##复制主库2的数据##
[mysqld3]
port = 3307
basedir = /usr/local/mysql
datadir = /data/mysql
character-set-server = utf8mb4
#指定实例2的sock文件和pid文件
socket = /tmp/mysql3.sock
pid-file=/data/mysql/mysql3.pid
skip-name-resolv = 1
open_files_limit = 65535 
back_log = 103
max_connections = 512
max_connect_errors = 100000
table_open_cache = 2048
tmp-table-size  = 32m
max-heap-table-size = 32m
query-cache-size = 0
external-locking = false
max_allowed_packet = 32m
sort_buffer_size = 2m
join_buffer_size = 2m
thread_cache_size = 51
query_cache_size = 32m
tmp_table_size = 96m
max_heap_table_size = 96m
query_cache_type=1
log-error=/data/logs/mysqld3.log
slow_query_log = 1
slow_query_log_file = /data/logs/slow3.log
long_query_time = 0.1
# binary logging #
# 这里一定要注意，不能把两个实例的binlog和relaylog放到同一个目录，
# 这里指定实例2的binlog日志为/data/binlog2目录
# 每个从库和每个实例的server_id不能一样。
server-id = 22
log-bin     = /data/binlog2/mysql-bin
log-bin-index  =/data/binlog2/mysql-bin.index
relay_log = /data/binlog2/mysql-relay-bin
relay_log_index = /data/binlog2/mysql-relay.index
master-info-file = /data/mysql/master3.info
relay_log_info_file = /data/mysql/relay-log3.info
read_only = 1
expire-logs-days = 14
sync_binlog = 1
#不需要复制的库
replicate-ignore-db = mysql,information_schema,performance_schema
binlog_cache_size = 4m
max_binlog_cache_size = 8m
max_binlog_size = 1024m
log_slave_updates =1
#binlog_format = row 
binlog_format = mixed
relay_log_recovery = 1
key_buffer_size = 32m
read_buffer_size = 1m
read_rnd_buffer_size = 16m
bulk_insert_buffer_size = 64m
myisam_sort_buffer_size = 128m
myisam_max_sort_file_size = 10g
myisam_repair_threads = 1
myisam_recover
#设置默认引擎为myisam
default-storage-engine=myisam
default-tmp-storage-engine=myisam
#关闭innodb引擎
skip-innodb
innodb = off
disable-innodb
#设置sql_mode模式为no_auto_create_user
sql_mode = no_auto_create_user
#关闭innodb引擎，下面这些参数一定要加上。
loose-skip-innodb
loose-innodb-trx=0 
loose-innodb-locks=0 
loose-innodb-lock-waits=0 
loose-innodb-cmp=0 
loose-innodb-cmp-per-index=0
loose-innodb-cmp-per-index-reset=0
loose-innodb-cmp-reset=0 
loose-innodb-cmpmem=0 
loose-innodb-cmpmem-reset=0 
loose-innodb-buffer-page=0 
loose-innodb-buffer-page-lru=0 
loose-innodb-buffer-pool-stats=0 
loose-innodb-metrics=0 
loose-innodb-ft-default-stopword=0 
loose-innodb-ft-inserted=0 
loose-innodb-ft-deleted=0 
loose-innodb-ft-being-deleted=0 
loose-innodb-ft-config=0 
loose-innodb-ft-index-cache=0 
loose-innodb-ft-index-table=0 
loose-innodb-sys-tables=0 
loose-innodb-sys-tablestats=0 
loose-innodb-sys-indexes=0 
loose-innodb-sys-columns=0 
loose-innodb-sys-fields=0 
loose-innodb-sys-foreign=0 
loose-innodb-sys-foreign-cols=0
[mysqldump]
quick
max_allowed_packet = 32m
```

3、设置主库sql_mode,mysql5.6默认需要在启动文件文件里面设置sql_mode才可以生效。

# cat /etc/init.d/mysqld
#other_args="$*"  # uncommon, but needed when called from an rpm upgrade action
      # expected: "--skip-networking --skip-grant-tables"
      # they are not checked here, intentionally, as it is the resposibility
      # of the "spec" file author to give correct arguments only.
#将上面默认的#other_args开启后改为
other_args="--sql-mode=no_auto_create_user"

4、开启主库和从库

#主库
service mysqld start
#开启从库的二个实例
/usr/local/mysql/bin/mysqld_multi start 2
/usr/local/mysql/bin/mysqld_multi start 3

5、在两台主库上面分别授权复制账号

#需要授权三个从库的ip可以同步
mysql> grant replication slave on *.* to rep@'192.168.1.3' identified by 'rep123';
mysql> grant replication slave on *.* to rep@'192.168.1.4' identified by 'rep123';
mysql> grant replication slave on *.* to rep@'192.168.1.5' identified by 'rep123';
mysql> flush privileges;

6、在三个从库分别开启同步。

#进入第一个实例执行
$ mysql -s /tmp/mysql.sock
mysql> change master to master_host='192.168.1.1',master_user='rep',master_password='rep123',master_log_file='mysql-bin.000001',master_log_pos=112;
 
#进入第二个实例执行
$ mysql -s /tmp/mysql3.sock
mysql> change master to master_host='192.168.1.2',master_user='rep',master_password='rep123',master_log_file='mysql-bin.000001',master_log_pos=112;

7、测试数据同步

在二个主数据库分别建表和插入数据，到从库查看可以看到二个主库同步到同一个从库上面的所有数据。

8、在每台从库服务器上设置任务计划每分钟刷新第一个实例的表

# crontab -l
*/1 * * * * mysql -s /tmp/mysql.sock -e 'flush tables;'

mysql5.6多主一从的坑

1、mysql5.6默认的引擎是innodb默认同步的时候一定要把主和从的sql_mode模式里面的no_engine_substitution这个参数关闭。如果不关闭innodb同步到从库上面的sql将会找不到innodb引擎导致同步失败。

2、在mysql5.6开启多实例的时候第一次启动的时候在你数据库的安装目录里面（/usr/local/mysql/)会生成my.cnf配置文件，默认会优先读取数据库安装目录里面的配置文件。导致多实例不生效。