trove/doc/source/install/get_started.rst

Database service overview

The Database service provides scalable and reliable cloud provisioning functionality for both relational and non-relational database engines. Users can quickly and easily use database features without the burden of handling complex administrative tasks. Cloud users and database administrators can provision and manage multiple database instances as needed.

The Database service provides resource isolation at high performance levels, and automates complex administrative tasks such as deployment, configuration, patching, backups, restores, and monitoring.

Process flow example

This example is a high-level process flow for using Database services:

1. The OpenStack Administrator configures the basic infrastructure using the following steps:
   1. Install the Database service.
   2. Create an image for each type of database. For example, one for MySQL and one for MongoDB.
   3. Use the trove-manage command to import images and offer them to tenants.
2. The OpenStack end user deploys the Database service using the following steps:

   1. Create a Database service instance using the openstack database instance create command.

   2. Use the openstack database instance list command to get the ID of the instance, followed by the openstack database instance show command to get the IP address of it.

   3. Access the Database service instance using typical database access commands. For example, with MySQL:

      $ mysql -u myuser -p -h TROVE_IP_ADDRESS mydb

Components

The Database service includes the following components:

python-troveclient command-line client

A CLI that communicates with the trove-api component.

trove-api component

This component is responsible for providing the RESTful API. It talks to the task manager for complex tasks, but it can also talk to the guest agent directly to perform simple tasks, such as retrieving databases or users from trove instance.

trove-conductor service

The conductor component is responsible for updating the Trove backend database with the information that the guest agent sends regarding the instances. It eliminates the need for direct database access by all the guest agents for updating information.

trove-taskmanager service

The task manager is the engine responsible for doing the majority of the work. It is responsible for provisioning instances, managing the life cycle, and performing different operations. The task manager normally sends common commands to trove guest agent, which are of an abstract nature; it is the responsibility of the guest agent to read them and issue database-specific commands in order to execute them.

trove-guestagent service

The guest agent runs inside the Nova instances that are used to run the database engines. The agent listens to the messaging bus for the topic and is responsible for actually translating and executing the commands that are sent to it by the task manager component for the particular datastore.