MySQL 5.7 supports different methods of replication. The traditional method is based on replicating events from the master's binary log, and requires the log files and positions in them to be synchronized between master and slave. The newer method based on global transaction identifiers (GTIDs) is transactional and therefore does not require working with log files or positions within these files, which greatly simplifies many common replication tasks. Replication using GTIDs guarantees consistency between master and slave as long as all transactions committed on the master have also been applied on the slave. For more information about GTIDs and GTID-based replication in MySQL, see Section 16.1.3, “Replication with Global Transaction Identifiers”. For information on using binary log file position based replication, seeSection 16.1, “Configuring Replication”.
Replication in MySQL supports different types of synchronization. The original type of synchronization is one-way, asynchronous replication, in which one server acts as the master, while one or more other servers act as slaves. This is in contrast to the synchronous replication which is a characteristic of NDB Cluster (see Chapter 21, MySQL NDB Cluster 7.5 and NDB Cluster 7.6). In MySQL 5.7, semisynchronous replication is supported in addition to the built-in asynchronous replication. With semisynchronous replication, a commit performed on the master blocks before returning to the session that performed the transaction until at least one slave acknowledges that it has received and logged the events for the transaction; see Section 16.3.9, “Semisynchronous Replication”. MySQL 5.7 also supports delayed replication such that a slave server deliberately lags behind the master by at least a specified amount of time; see Section 16.3.10, “Delayed Replication”. For scenarios where synchronous replication is required, use NDB Cluster (see Chapter 21, MySQL NDB Cluster 7.5 and NDB Cluster 7.6).
MySQL Shell includes the AdminAPI, which is accessed through the dba global variable and its associated methods. The dba variable's methods enable you to deploy, configure, and administer InnoDB clusters. For example, use thedba.createCluster() method to create an InnoDB cluster.
Important
MySQL Shell enables you to connect to servers over a socket connection, but AdminAPI requires TCP connections to a server instance. Do not use socket based connections with AdminAPI.
Group Replication members can contain tables using a storage engine other than InnoDB, for example MyISAM. Such tables cannot be written to by Group Replication, and therefore when using InnoDB cluster. To be able to write to such tables with InnoDB cluster, convert all such tables to InnoDB before using the instance in a InnoDB cluster.
https://dev.mysql.com/doc/refman/5.7/en/mysql-innodb-cluster-introduction.html