Cloud SQL is service for relational database in google cloud platform and fully manage by Google. Cloud SQL support mysql 5.6 (will be deprecete on march 2020), PostgreSql and Sql server. CloudSQl ensures your instance for the database is updated, patch, and backup. GCP provide SLA 99,5% for this servece. You can chose variant from MySql 5.6-5.7 or PgSql 9.6-11 or SQL Server 2017 (Beta).
Since the isntance is managed by Google, you don’t need too worry about backup, ha or replication configuration. All in one click in the Gcloud console interface. Thi service also provide setup to migratio your database from your premisess as master to the Cloud SQL as the slave.
Unfortunally if the replication on the Cloud SQL is using GTID. So you can’t use any database with view or temporary table on your database in order to make the replication work. You can use it in single instance only if you have those kind of tables.