RANGER-5736: Fix MariaDB grant failure during Ranger Admin DB setup

[ramackri]

Summary

Fixes Ranger Admin and KMS database setup failure on MariaDB when dba_script.py grants privileges to a host-specific admin user (e.g. 'rangeradmin'@'ranger-db' or 'rangerkms'@'ranger-db.rangernw'). MariaDB returns MySQL error 1133 (Can't find any matching row in the user table) after wildcard/localhost grants when FLUSH PRIVILEGES runs between grants.

Ranger Docker's DB_FLAVOR=MYSQL path uses MariaDB (Dockerfile.ranger-mysql), not Oracle MySQL Server. This change detects MariaDB at runtime via SELECT VERSION() and applies MariaDB-specific grant order, flush timing, and a one-time user recreate/retry on failure. Oracle MySQL and all other DB flavor classes (PostgresConf, OracleConf, SqlServerConf, SqlAnywhereConf) are unchanged.

Jira: https://issues.apache.org/jira/browse/RANGER-5736

Changes

• Detect MariaDB in MysqlConf using SELECT VERSION() in both security-admin/scripts/dba_script.py and kms/scripts/dba_script.py
• MariaDB only: grant @db_host before @'%' / @'localhost', run FLUSH PRIVILEGES once at the end, drop/recreate user and retry grant once on failure
• Non-MariaDB MySQL: preserve original grant order and flush-after-each-grant behavior
• Add detect_server_type() and user_hosts() helpers; keep grant/flush logic inline in grant_xa_db_user()
• No changes to init_mysql.sql or other DB flavor setup paths

Manual testing — Ranger Admin

Ran security-admin/scripts/dba_script.py -q (JDK 17) against Docker-backed databases using the corresponding Ranger Admin install properties (db_host=ranger-db where applicable):

DB flavor	Server	Result	Notes
MYSQL (MariaDB path)	MariaDB 10.7.3 + init_mysql.sql	PASS	Host-specific grant first; single FLUSH; recreate/retry if needed
MYSQL (non-MariaDB path)	Oracle MySQL 8.0.36 + init_mysql.sql	PASS	Original grant/flush sequence preserved
POSTGRES	PostgreSQL 13.16	PASS	No MariaDB logic involved
MSSQL	SQL Server 2022	PASS	No MariaDB logic involved
ORACLE	Oracle Free 23	PASS	No MariaDB logic involved
SQLA (SQL Anywhere)	—	Not tested	No SQL Anywhere image in ranger-docker

Verified the original failure is reproducible on MariaDB 10.7.3 and 10.11 with the pre-fix grant+flush sequence, and that the patched script completes successfully on MariaDB without modifying init_mysql.sql.

Manual testing — Ranger KMS

Mirrored the same MysqlConf fix in kms/scripts/dba_script.py (KMS Docker hits the same 1133 grant failure). Ran kms/scripts/dba_script.py -q (JDK 17) using KMS Docker install properties (db_host=ranger-db.rangernw, db_user=rangerkms, db_name=rangerkms):

DB flavor	Server	Result	Notes
MYSQL (MariaDB path)	MariaDB 10.7.3	PASS	Grants 'rangerkms'@'ranger-db.rangernw' first; single FLUSH at end
MYSQL (non-MariaDB path)	Oracle MySQL 8.0.36	PASS	Non-MariaDB path; per-grant FLUSH preserved
POSTGRES	PostgreSQL 13.16	PASS	No MariaDB logic involved
MSSQL	SQL Server 2022	PASS	Requires rangerkms DB + login/user (same as Docker init_mssql.sh)
ORACLE	Oracle Free 23.6	PASS	No MariaDB logic involved
SQLA (SQL Anywhere)	—	Not tested	No SQL Anywhere image in ranger-docker