Cassandra is an open source distributed database administrator designed to handle large volumes of data spread across multiple nodes while ensuring high availability, or scalability.
Reduce the number of flexible nodes (Elastic Scalability) and accept some errors (Fault Tolerant). It was developed by Facebook and is still growing and used for the largest social network in the world. In 2008, Facebook passed it over to the open source community and continues to grow by Apache today. Cassandra is considered a combination of Amazon’s Dynamo and Google’s BigTable.
Log in to Cassandra
# / CassandraPath / bin / cqlsh <localhost or ip server> -u cassandra -p cassandra
cassandra : default user / pass
Create User
Syntax
CREATE USER 'user_name' WITH PASSWORD 'password' NOSUPERUSER / SUPERUSER;
| Syntax explanation | Meaning |
|---|---|
| CREATE USER | Create user |
| username / password | User name and password |
NOSUPERUSER/SUPERUSER |
Regular User or Super User |
If there is an error message:
InvalidRequest: Error from server: code = 2200 [Invalid query] message = “remoteuser already exists”
That is, the user you want to create already exists, you can use the following command:
CREATE USER IF NOT EXISTS user_name WITH PASSWORD 'password';
IF NOT EXISTS: If user_name already exists , it will still execute without error.
For example
CREATE USER IF NOT EXISTS remoteuser WITH PASSWORD ' Admin @ 123 ';
Test the user after creating it
cassandra @ cqlsh > list users;
Authorize the user
Syntax
GRANT permission_name ON resource TO user_name
In it, permission_name includes:
| Permission | CQL Statement |
|---|---|
| ALL | All statements |
| ALTER | ALTER KEYSPACE, ALTER TABLE, CREATE INDEX, DROP INDEX |
| AUTHORIZE | GRANT, REVOKE |
| CREATE | CREATE KEYSPACE, CREATE TABLE |
| DROP | DROP KEYSPACE, DROP TABLE |
| MODIFY | INSERT, DELETE, UPDATE, TRUNCATE |
| SELECT | SELECT |
Resources include:
- ALL KEYSPACES
- KEYSPACE keyspace_name
- TABLE keyspace_name. table_name
For example
GRANT ALL ON ALL KEYSPACES TO remoteuser;
Check permissions for remoteuser:
Good luck.
