Keystone-schema-in-cassandra
Contents
Introduction
The purpose of this wiki article is to describe the Cassandra tables for each of the backends of Keystone. A discussion of the general concepts related to schema design in Cassandra has been covered separately.
Identity
The identity backend of Keystone holds data for users, groups and user-group membership. There are three tables in the MySQL DB for this purpose.
- user
- group
- user_group_membership
The user Table
The user table in MySQL is as follows.
id | domain_id | name | enabled | password | extra | default_project_id |
---|---|---|---|---|---|---|
Primary Key: (id), Unique Key: (domain_id, name) |
The operations pertaining to this table rely on being able to access data given one of the following sets of columns: (domain_id), (domain_id, name), (id). The equivalent operations in Cassandra are supported by the following two tables.
id | domain_id | name | enabled | password | extra | default_project_id |
---|---|---|---|---|---|---|
Primary Key: (id) |
domain_id | name | id |
---|---|---|
Primary Key: (domain_id, name) |
The group table
The group table in MySQL is similar to the user table, and is as follows.
id | domain_id | name | extra | description |
---|---|---|---|---|
Primary Key: (id), Unique Key: (domain_id, name) |
The operations pertaining to this table rely on being able to access data given one of the following sets of columns: (domain_id), (domain_id, name), (id). Keeping the equivalent data in Cassandra is done similarly to what was done with the user table, i.e., with two Cassandra tables as follows.
id | domain_id | name | extra | description |
---|---|---|---|---|
Primary Key: (id) |
domain_id | name | id |
---|---|---|
Primary Key: (domain_id, name) |
The user_group_membership Table
The user_group_membership table used in MySQL is as follows.
user_id | group_id |
---|---|
Primary Key: (user_id, group_id), Key: (group_id) |
The operations pertaining to this table rely on accessing data given one of the following sets of columns: (user_id), (user_id, group_id), (group_id), or (group_id, user_id). There are two tables in Cassandra to store user_group_membership. All the insert, update and delete go to both the tables in Cassandra.
user_id | group_id |
---|---|
Primary Key: (user_id, group_id); clustering column: group_id |
group_id | user_id |
---|---|
Primary Key: (group_id, user_id); clustering column: user_id |
Assignment
The assignment backend holds data about the role assignments. It additionally has a "role backend" which stores data for all the roles. There are two tables in the MySQL DB.
- assignment
- role
The assignment Table
The assignment table in MySQL is as follows.
type | actor_id | target_id | role_id | inherited |
---|---|---|---|---|
Primary Key: (type, actor_id, target_id, role_id), Key: (actor_id), Key: (role_id) |
The operations pertaining to this table are based on one of the following sets of columns: (type, actor_id, target_id, role_id), (type, actor_id, target_id), (actor_id), (target_id), or (role_id). This table looks the same in Cassandra. Additionally there are two secondary index on columns target_id and role_id. These are intended to be used when a role_id or target_id is deleted from Keystone.
Note: Since the Hierarchical Multi-Tenancy feature is not yet included in this schema design, the inherited column has been omitted from the Cassandra schema.
type | actor_id | target_id | role_id |
---|---|---|---|
Primary Key: (type, actor_id, target_id, role_id), Secondary Indices: (target_id) and (role_id) |
The role Table
The role table in MySQL is as follows.
id | name | extra |
---|---|---|
Primary Key: (id), Unique Key: (name) |
Most of the operations on this table are done based on role_id. There is an api in v2.0 which allows the client to get a role by its name. So we need the name to id mapping in second table. To preserve the uniqueness of the name, a row is first inserted to the role_name_index table. If that succeeds then the row is inserted to the role table. The equivalent in Cassandra is two tables.
id | name | extra |
---|---|---|
Primary Key: (id) |
name | id |
---|---|
Primary Key: (name) |
Resource
The resource backend holds data about projects and domains. There are two tables in this backend.
- project
- domain
The project Table
The project table in MySQL is as follows.
id | domain_id | name | enabled | description | extra | parent_id |
---|---|---|---|---|---|---|
Primary Key:(id), Unique Key: (domain_id, name), Key: (parent_id) |
The operations pertaining to this table are based on one of the following sets of columns: (id), (domain_id), or (domain_id, name). Currently, this schema does not account for Hierarchical Multi Tenancy, which will be done later. If we leave out the parent_id part in this table, then this table looks exactly similar to user table and also is modeled exactly the same.
id | domain_id | name | enabled | extra | description |
---|---|---|---|---|---|
Primary Key: (id) |
domain_id | name | id |
---|---|---|
Primary Key: (domain_id, name) |
The domain Table
The domain table in MySQL is as follows.
id | name | extra |
---|---|---|
Primary Key: (id), Unique Key: (name) |
The operations on this table are based on the id column. These operations are supported by following tables in Cassandra.
id | name | extra |
---|---|---|
Primary Key: (id) |
name | id |
---|---|
Primary Key: (name) |
Credential
The Credential backend holds data related to EC2 credentials. It has one table.
The credential Table
The credential table in MySQL is as follows.
id | user_id | project_id | blob | type | extra | |
---|---|---|---|---|---|---|
Primary Key: (id) |
The operations pertaining to this table are based on one of the following columns: (id), (user_id), or (project_id). These operations are supported by the following Cassandra table. Additionally as an optimization later, secondary indices can be created on columns user_id and project_id.
id | user_id | project_id | blob | type | extra | |
---|---|---|---|---|---|---|
Primary Key: (id) |
Trust
The Trust backend stores data related to trust delegation functionality offered to users.
The trust Table
There are two tables pertaining to this backend. They are as follows.
id | trustor_user_id | trustee_user_id | project_id | impersonation | deleted_at | expires_at | remaining_uses | extra | |
---|---|---|---|---|---|---|---|---|---|
Primary Key: (id) |
trust_id | role_id |
---|---|
Primary Key: (trust_id, role_id) |
These two tables can be combined into one in Cassandra and the roles would be a stored as a set. (Note: Cassandra provides support for richer data types such as list, map, set etc.)
id | trustor_user_id | trustee_user_id | project_id | impersonation | deleted_at | expires_at | remaining_uses | extra | roles(set) |
---|---|---|---|---|---|---|---|---|---|
Primary Key: (id) |