You can create a replica of an existing database instance. When you make subsequent changes to the original instance, the system automatically applies those changes to the replica.
This example shows you how to replicate a MySQL database instance.
Get the instance ID
Get the ID of the original instance you want to replicate:
$ trove list
+-----------+------------+-----------+-------------------+--------+-----------+------+
| id | name | datastore | datastore_version | status | flavor_id | size |
+-----------+------------+-----------+-------------------+--------+-----------+------+
| 97b...ae6 | base_1 | mysql | mysql-5.5 | ACTIVE | 10 | 2 |
+-----------+------------+-----------+-------------------+--------+-----------+------+
Create the replica
Create a new instance that will be a replica of the original instance. You do this by passing in the --replica_of option with the trove create command. This example creates a replica called replica_1. replica_1 is a replica of the original instance, base_1:
$ trove create replica_1 6 --size=5 --datastore_version mysql-5.5 \
--datastore mysql --replica_of ID_OF_ORIGINAL_INSTANCE
Verify replication status
Pass in replica_1‘s instance ID with the trove show command to verify that the newly created replica_1 instance is a replica of the original base_1. Note that the replica_of property is set to the ID of base_1.
$ trove show INSTANCE_ID_OF_REPLICA_1
+-------------------+--------------------------------------+
| Property | Value |
+-------------------+--------------------------------------+
| created | 2014-09-16T11:16:49 |
| datastore | mysql |
| datastore_version | mysql-5.5 |
| flavor | 6 |
| id | 49c6eff6-ef91-4eff-91c0-efbda7e83c38 |
| name | replica_1 |
| replica_of | 97b4b853-80f6-414f-ba6f-c6f455a79ae6 |
| status | BUILD |
| updated | 2014-09-16T11:16:49 |
| volume | 5 |
+-------------------+--------------------------------------+
Now pass in base_1‘s instance ID with the trove show command to list the replica(s) associated with the original instance. Note that the replicas property is set to the ID of replica_1. If there are multiple replicas, they appear as a comma-separated list.
$ trove show INSTANCE_ID_OF_BASE_1
+-------------------+--------------------------------------+
| Property | Value |
+-------------------+--------------------------------------+
| created | 2014-09-16T11:04:56 |
| datastore | mysql |
| datastore_version | mysql-5.5 |
| flavor | 6 |
| id | 97b4b853-80f6-414f-ba6f-c6f455a79ae6 |
| ip | 172.16.200.2 |
| name | base_1 |
| replicas | 49c6eff6-ef91-4eff-91c0-efbda7e83c38 |
| status | ACTIVE |
| updated | 2014-09-16T11:05:06 |
| volume | 5 |
| volume_used | 0.11 |
+-------------------+--------------------------------------+
Detach the replica
If the original instance goes down, you can detach the replica. The replica becomes a standalone database instance. You can then take the new standalone instance and create a new replica of that instance.
You detach a replica using the trove detach-replica command:
$ trove detach-replica INSTANCE_ID_OF_REPLICA
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