MySQL高可用架构InnoDB Cluster (和NDB Cluster是两码事)

MySQL的高可用架构无论是社区还是官方，一直在技术上进行探索，这么多年提出了多种解决方案，比如MMM, MHA, NDB Cluster, Galera Cluster, InnoDB Cluster, 腾讯的PhxSQL, MySQL Fabric. 本文主要介绍MySQL的高可用架构InnoDB Cluster。 MySQL InnoDB Cluster解决方案其实是由MySQL的几个不同产品和技术组成的，比如MySQL Shell, MySQL Router, Group Replication.

安装mysql, mysql shell, mysql router
略

部署多个实例 

mysqlsh
mysql-js> dba.deployLocalInstance(3310)
mysql-js> dba.deployLocalInstance(3320)
mysql-js> dba.deployLocalInstance(3330)

3310作为master, 3320和3330作为slave

创建集群
mysql-js> \c root@localhost:3310
mysql-js> cluster = dba.createCluster('mycluster')
向集群添加实例 
mysql-js> cluster.addInstance("root@localhost:3320")
mysql-js> cluster.addInstance("root@localhost:3330")
查看集群状态
mysql-js> cluster.status()
{
    "clusterName": "mycluster",
    "defaultReplicaSet": {
        "status": "Cluster tolerant to up to ONE failure.",
        "topology": {
            "localhost:3310": {
                "address": "localhost:3310",
                "status": "ONLINE",
                "role": "HA",
                "mode": "R/W",
                "leaves": {
                    "localhost:3330": {
                        "address": "localhost:3330",
                        "status": "ONLINE",
                        "role": "HA",
                        "mode": "R/O",
                        "leaves": {}
                    },
                    "localhost:3320": {
                        "address": "localhost:3320",
                        "status": "ONLINE",
                        "role": "HA",
                        "mode": "R/O",
                        "leaves": {}
                    }
                }
            }
        }
    }
}

部署MySQL Router
mysqlrouter --bootstrap localhost:3310
返回信息
...
Please enter the administrative MASTER key for the MySQL InnoDB cluster:
MySQL Router has now been configured for the InnoDB cluster 'mycluster'.


The following connection information can be used to connect to the cluster.


Classic MySQL protocol connections to cluster 'mycluster':
- Read/Write Connections: localhost:6446
- Read/Only Connections: localhost:6447

启动Mysql Router

mysqlrouter&

客户端连接Router
mysqlsh --uri root@localhost:6446
mysql-js> \sql
Switching to SQL mode... Commands end with ;


mysql-sql> select @@port;
+--------+
| @@port |
+--------+
|   3310 |
+--------+
1 row in set (0.00 sec)


故障模拟
mysql-js> dba.killLocalInstance(3310)
切换到sql模式，执行sql语句Select @@port
mysql-js> \sql
Switching to SQL mode... Commands end with ;


mysql-sql> SELECT @@port;
ERROR: 2013 (HY000): Lost connection to MySQL server during query
The global session got disconnected.
Attempting to reconnect to 'root@localhost:6446'...
The global session was successfully reconnected.


mysql-sql> SELECT @@port;
+--------+
| @@port |
+--------+
|   3330 |
+--------+
1 row in set (0.00 sec)
可以看到，故障被检查到了，并自动重连，转到了 3330 实例


参考资料
https://dev.mysql.com/doc/refman/5.7/en/mysql-innodb-cluster-userguide.html
http://mysqlserverteam.com/mysql-innodb-cluster-setting-up-a-real-world-cluster/