Datastore

Introduction

Admin user needs to create datastore and its versions as required.

A datastore is typically created as a type of database, e.g. the cloud admin could create 2 datastores for MySQL and PostgreSQL, separately. For each datastore, there could be multiple datastore versions. For example, for MySQL database, Trove could support 5.7.29, 5.7.30 or 5.8, etc.

Note

Starting from Victoria, the datastore version number must be the same with the image tag of the specific database. To support MySQL 5.7.29, a new datastore version with version number 5.7.29 based on mysql docker image needs to be created.

A datastore version is always associated with a Glance image, either by image ID or image tags. If the image ID is not provided, the image can be retrieved by the image tags. The tags are used for filtering as a whole rather than separately. Using image tags is more flexible than ID especially when a new guest image is uploaded to Glance, Trove can pick up the latest image automatically for creating instances.

Create datastore version

When creating a datastore version, Trove will create the datastore first if it doesn’t exist. Different datastore versions can have the same name but different version numbers, or same version number but different names.

When using image tags, make sure the image with the tags exists before creating the datastore version.

Note

From Victoria release, all the datastores can be configured with a same Glance image but with different datastore name and version name.

To create a datastore version:

1. Create a trove guest image

   Refer to Build images using trovestack

2. Register image with Image service

   You need to register your guest image with the Image service as cloud admin. In this example, the image is assigned tags that will be used when creating datastore version.

   openstack image create \
     trove-guest-ubuntu-focal \
     --private \
     --disk-format qcow2 --container-format bare \
     --file $image_file \
     --property hw_rng_model='virtio' \
     --tag trove --tag mysql
   

3. Create the datastore version

   openstack datastore version create 5.7.29 mysql mysql "" \
     --image-tags trove,mysql \
     --active --default \
     --version-number 5.7.29
   

4. Load validation rules for configuration groups

   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 openstack database 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 18.04	/usr/lib/python3/dist-packages/trove/templates/DATASTORE_NAME	DATASTORE_NAME is the name of the datastore, e.g. mysql or postgresql.
   RHEL 7, CentOS 7, Fedora 20, and Fedora 21	/usr/lib/python3/site-packages/trove/templates/DATASTORE_NAME	DATASTORE_NAME is the name of the datastore, e.g. mysql or postgresql.

   
   

   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 on trove controller node. 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 18.04:

   $ trove-manage db_load_datastore_config_parameters mysql 5.7.29 /usr/lib/python3/dist-packages/trove/templates/mysql/validation-rules.json
   

Hide a datastore version

Sometimes, it’s needed to make a datastore version invisible to the cloud users, e.g when a datastore version is deprecated or creating a datastore version for testing purpose, to do that:

$ openstack datastore version set <version-id> --disable

Replace image ID with tags

For datastore versions that are created using image ID, it’s easy to switch to image tags without affecting the existing instances. New instances will be created by the image ID (the most recently uploaded) that getting from Glance using image tags. To do that, as the cloud admin user:

$ openstack datastore version set <version-id> --image-tags trove,mysql

Ignoring --image means removing the image ID from the datastore version if it’s associated.