openstack-manuals/doc/admin-guide/source/database.rst

Database

The Database service provides database management features.

Introduction

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.

You can modify various cluster characteristics by editing the /etc/trove/trove.conf file. A comprehensive list of the Database service configuration options is described in the Database service chapter in the Configuration Reference.

Create a data store

An administrative user can create data stores for a variety of databases.

This section assumes you do not yet have a MySQL data store, and shows you how to create a MySQL data store and populate it with a MySQL 5.5 data store version.

To create a data store

1. Create a trove image

   Create an image for the type of database you want to use, for example, MySQL, MongoDB, Cassandra.

   This image must have the trove guest agent installed, and it must have the trove-guestagent.conf file configured to connect to your OpenStack environment. To configure trove-guestagent.conf, add the following lines to trove-guestagent.conf on the guest instance you are using to build your image:

   rabbit_host = controller
   rabbit_password = RABBIT_PASS
   nova_proxy_admin_user = admin
   nova_proxy_admin_pass = ADMIN_PASS
   nova_proxy_admin_tenant_name = service
   trove_auth_url = http://controller:35357/v2.0

   This example assumes you have created a MySQL 5.5 image called mysql-5.5.qcow2.

   Important

   If you have a guest image that was created with an OpenStack version before Kilo, modify the guest agent init script for the guest image to read the configuration files from the directory /etc/trove/conf.d.

   For a backwards compatibility with pre-Kilo guest instances, set the database service configuration options injected_config_location to /etc/trove and guest_info to /etc/guest_info.

2. Register image with Image service

   You need to register your guest image with the Image service.

   In this example, you use the glance image-create command to register a mysql-5.5.qcow2 image.

   $ glance image-create --name mysql-5.5 --disk-format qcow2 --container-format bare --is-public True < mysql-5.5.qcow2
   +------------------+--------------------------------------+
   | Property         | Value                                |
   +------------------+--------------------------------------+
   | checksum         | d41d8cd98f00b204e9800998ecf8427e     |
   | container_format | bare                                 |
   | created_at       | 2014-05-23T21:01:18                  |
   | deleted          | False                                |
   | deleted_at       | None                                 |
   | disk_format      | qcow2                                |
   | id               | bb75f870-0c33-4907-8467-1367f8cb15b6 |
   | is_public        | True                                 |
   | min_disk         | 0                                    |
   | min_ram          | 0                                    |
   | name             | mysql-5.5                            |
   | owner            | 1448da1223124bb291f5ae8e9af4270d     |
   | protected        | False                                |
   | size             | 0                                    |
   | status           | active                               |
   | updated_at       | 2014-05-23T21:01:22                  |
   | virtual_size     | None                                 |
   +------------------+--------------------------------------+

3. Create the data store

   Create the data store that will house the new image. To do this, use the trove-manage datastore_update command.

   This example uses the following arguments:

   Argument	Description	In this example:
   config file	The configuration file to use.	--config-file=/etc/trove/trove.conf
   name	Name you want to use for this data store.	mysql
   default version	You can attach multiple versions/images to a data store. For example, you might have a MySQL 5.5 version and a MySQL 5.6 version. You can designate one version as the default, which the system uses if a user does not explicitly request a specific version.	"" At this point, you do not yet have a default version, so pass in an empty string.

   Example:

   $ trove-manage --config-file=/etc/trove/trove.conf datastore_update mysql ""

4. Add a version to the new data store

   Now that you have a MySQL data store, you can add a version to it, using the trove-manage datastore_version_update command. The version indicates which guest image to use.

   This example uses the following arguments:

   Argument	Description	In this example:
   config file	The configuration file to use.	--config-file=/etc/trove/trove.conf
   data store	The name of the data store you just created via trove-manage datastore_update.	mysql
   version name	The name of the version you are adding to the data store.	mysql-5.5
   data store manager	Which data store manager to use for this version. Typically, the data store manager is identified by one of the following strings, depending on the database: cassandra couchbase couchdb db2 mariadb mongodb mysql percona postgresql pxc redis vertica	mysql
   glance ID	The ID of the guest image you just added to the Image service. You can get this ID by using the glance image-show IMAGE_NAME command.	bb75f870-0c33-4907-8467-1367f8cb15b6
   packages	If you want to put additional packages on each guest that you create with this data store version, you can list the package names here.	"" In this example, the guest image already contains all the required packages, so leave this argument empty.
   active	Set this to either 1 or 0: 1 = active 0 = disabled	1

   Example:

   $ trove-manage --config-file=/etc/trove/trove.conf datastore_version_update mysql mysql-5.5 mysql GLANCE_ID "" 1

   Optional. Set your new version as the default version. To do this, use the trove-manage datastore_update command again, this time specifying the version you just created.

   $ trove-manage --config-file=/etc/trove/trove.conf datastore_update mysql mysql-5.5

5. Load validation rules for configuration groups

   Note

   Applies only to MySQL and Percona data stores

   • If you just created a MySQL or Percona data store, then you need to load the appropriate validation rules, as described in this step.
   • If you just created a different data store, skip this step.

   Background. You can manage database configuration tasks by using configuration groups. Configuration groups let you set configuration parameters, in bulk, on one or more databases.

   When you set up a configuration group using the trove configuration-create command, this command compares the configuration values you are setting against a list of valid configuration values that are stored in the validation-rules.json file.

   Operating System	Location of validation-rules.json	Notes
   Ubuntu 14.04	/usr/lib/python2.7/dist-packages/trove/templates/DATASTORE_NAME	DATASTORE_NAME is the name of either the MySQL data store or the Percona data store. This is typically either mysql or percona.
   RHEL 7, CentOS 7, Fedora 20, and Fedora 21	/usr/lib/python2.7/site-packages/trove/templates/DATASTORE_NAME	DATASTORE_NAME is the name of either the MySQL data store or the Percona data store. This is typically either mysql or percona.

   Therefore, as part of creating a data store, you need to load the validation-rules.json file, using the trove-manage db_load_datastore_config_parameters command. This command takes the following arguments:

   • Data store name
   • Data store version
   • Full path to the validation-rules.json file

   This example loads the validation-rules.json file for a MySQL database on Ubuntu 14.04:

   $ trove-manage db_load_datastore_config_parameters mysql mysql-5.5 /usr/lib/python2.7/dist-packages/trove/templates/mysql/validation-rules.json

6. Validate data store

   To validate your new data store and version, start by listing the data stores on your system:

   $ trove datastore-list
   +--------------------------------------+--------------+
   |                  id                  |     name     |
   +--------------------------------------+--------------+
   | 10000000-0000-0000-0000-000000000001 | Legacy MySQL |
   | e5dc1da3-f080-4589-a4c2-eff7928f969a |    mysql     |
   +--------------------------------------+--------------+

   Take the ID of the MySQL data store and pass it in with the datastore-version-list command:

   $ trove datastore-version-list DATASTORE_ID
   +--------------------------------------+-----------+
   |                  id                  |    name   |
   +--------------------------------------+-----------+
   | 36a6306b-efd8-4d83-9b75-8b30dd756381 | mysql-5.5 |
   +--------------------------------------+-----------+

Data store classifications

The Database service supports a variety of both relational and non-relational database engines, but to a varying degree of support for each data store. The Database service project has defined several classifications that indicate the quality of support for each data store. Data stores also implement different extensions. An extension is called a strategy and is classified similar to data stores.

Valid classifications for a data store and a strategy are:

• Experimental
• Technical preview
• Stable

Each classification builds on the previous one. This means that a data store that meets the technical preview requirements must also meet all the requirements for experimental, and a data store that meets the stable requirements must also meet all the requirements for technical preview.

Requirements

• Experimental

  A data store is considered to be experimental if it meets these criteria:

  • It implements a basic subset of the Database service API including create and delete.
  • It has guest agent elements that allow guest agent creation.
  • It has a definition of supported operating systems.
  • It meets the other Documented Technical Requirements.

  A strategy is considered experimental if:

  • It meets the Documented Technical Requirements.

• Technical preview

  A data store is considered to be a technical preview if it meets the requirements of experimental and further:

  • It implements APIs required to plant and start the capabilities of the data store as defined in the Datastore Compatibility Matrix.

    Note

    It is not required that the data store implements all features like resize, backup, replication, or clustering to meet this classification.

  • It provides a mechanism for building a guest image that allows you to exercise its capabilities.

  • It meets the other Documented Technical Requirements.

  Important

  A strategy is not normally considered to be technical preview.

• Stable

  A data store or a strategy is considered stable if:

  • It meets the requirements of technical preview.
  • It meets the other Documented Technical Requirements.

Initial Classifications

The following table shows the current classification assignments for the different data stores.

Classification	Data store
Stable	MySQL
Technical Preview	Cassandra, MongoDB
Experimental	All others

Redis data store replication

Replication strategies are available for Redis with several commands located in the Redis data store manager:

• create
• detach-replica
• eject-replica-source
• promote-to-replica-source

Additional arguments for the create command include --replica_of and --replica_count.

Redis integration and unit tests

Unit tests and integration tests are also available for Redis.

1. Install redstack:

   $ ./redstack install
   
   .. note::
   
      Redstack is a development script used for integration
      testing and Database service development installations.
      Do not use Redstack in a production environment. For
      more information, see `the Database service
      developer docs <http://docs.openstack.org/developer/trove/dev/install.html#running-redstack-to-install-trove>`_

2. Start Redis:

   $ ./redstack kick-start redis

3. Run integration tests:

   $ ./redstack int-tests --group=replication

   You can run --group=redis_supported instead of --group=replication if needed.

Configure a cluster

An administrative user can configure various characteristics of a MongoDB cluster.

Query routers and config servers

Background. Each cluster includes at least one query router and one config server. Query routers and config servers count against your quota. When you delete a cluster, the system deletes the associated query router(s) and config server(s).

Configuration. By default, the system creates one query router and one config server per cluster. You can change this by editing the /etc/trove/trove.conf file. These settings are in the mongodb section of the file:

Setting	Valid values are:
num_config_servers_per_cluster	1 or 3
num_query_routers_per_cluster	1 or 3