AWS RDS Can't complete Blue / Green changeover

Question

I'm trying to do a Blue / Green changeover but it's failing with the error:

Switchover from DB cluster asamazon2-cluster to asamazon2-cluster-green-xxxx was canceled due to external replication on asamazon2-cluster. Stop replication from an external database to asamazon2-cluster before you switch over.

If I do slow slave status on the Blue database I get:

    Slave_IO_State: 
                  Master_Host: 221.121.140.xxx
                  Master_User: xxx
                  Master_Port: 3306
                Connect_Retry: 60
              Master_Log_File: mysql-bin-changelog.000016
          Read_Master_Log_Pos: 904410367
               Relay_Log_File: relaylog.205102
                Relay_Log_Pos: 4
        Relay_Master_Log_File: mysql-bin-changelog.000016
             Slave_IO_Running: No
            Slave_SQL_Running: No
              Replicate_Do_DB: 
          Replicate_Ignore_DB: 
           Replicate_Do_Table: 
       Replicate_Ignore_Table: mysql.rds_replication_status,mysql.rds_monitor,mysql.rds_sysinfo,mysql.rds_configuration,mysql.rds_history
      Replicate_Wild_Do_Table: 
  Replicate_Wild_Ignore_Table: 
                   Last_Errno: 0
                   Last_Error: 
                 Skip_Counter: 0
          Exec_Master_Log_Pos: 904410367
              Relay_Log_Space: 23318298
              Until_Condition: None
               Until_Log_File: 
                Until_Log_Pos: 0
           Master_SSL_Allowed: No
           Master_SSL_CA_File: 
           Master_SSL_CA_Path: 
              Master_SSL_Cert: 
            Master_SSL_Cipher: 
               Master_SSL_Key: 
        Seconds_Behind_Master: NULL
Master_SSL_Verify_Server_Cert: No
                Last_IO_Errno: 0
                Last_IO_Error: 
               Last_SQL_Errno: 0
               Last_SQL_Error: 
  Replicate_Ignore_Server_Ids: 
             Master_Server_Id: 0
                  Master_UUID: 
             Master_Info_File: mysql.slave_master_info
                    SQL_Delay: 0
          SQL_Remaining_Delay: NULL
      Slave_SQL_Running_State: 
           Master_Retry_Count: 86400
                  Master_Bind: 
      Last_IO_Error_Timestamp: 
     Last_SQL_Error_Timestamp: 
               Master_SSL_Crl: 
           Master_SSL_Crlpath: 
           Retrieved_Gtid_Set: 
            Executed_Gtid_Set: 
                Auto_Position: 0

I tried stop slave as root user but got a permission denied error.

Have also tried "CALL mysstop_replication;", but get the message " Slave is already stopped or may not be configured. Run SHOW SLAVE STATUS\G"

The cluster shouldn't actually be a slave as it's not being synchronised by an external source and has been running independently for several years.

Can't seem to find any information on how to sort this out. Any help appreciated.

Answer 1

We had this issues today as well and it was fixed by running CALL mysql.rds_reset_external_master; on the master/writer node. Our issue was caused by doing a manual replication to upgrade in the pass and never disabling this post promotion of the master node.