Sentry是一个RPC服务，将认证元数据信息存储在关系型数据库，并提供RPC接口检索和操作权限。利用Kerveros支持安全访问。Sentry Service通过后台数据库存储提供认证元数据信息，不处理真实的权限验证，当Hive,Impala等服务的配置使用Sentry权限的时候，Hive，Impala只作为Sentry的client。

    最早的Sentry是使用policy file配置权限，逐渐版本升级过程中，目前采用关系型数据库存储权限角色等。使用新的Sentry服务相比于旧的policy file能够更容易处理用户权限，新的Sentry服务提供了更传统的 GRANT/REVOKE语句修改权限。


早版本Sentry中的策略文件policy file:

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[groups] 
manager = customers_insert_role, 
customers_select_role
analyst = customers_select_role 
[roles] 
customers_insert_role = server=server1->db=customers->table=*->action= insert 
customers_select_role = server=server1->db=customers->table=*->action=select


Sentry历史版本功能：

  • Sentry with policy files is added in CDH 5.1.0.

  • Sentry with config support is added in CDH 5.5.0.

  • Sentry with database-backed Sentry service is added with CDH 5.8.0.



Sentry中基础名词：

1.object Sentry认证规则所保护的一个对象，包括 server, database, table, URI, collection, and config

2.role 访问给定object的规则集合

3.privilege 包括insert select update等

4.user 来自于能够访问Sentry服务的一个认证系统用户，user可以是Kerberos的principal, LDAP的userid，或其他认证系统的标识

5.group 组，一个或者多个用户的集合，Sentry中将role分配给group，一个组就相应担当某个角色

6.A configured group provider determines a user’s affiliation with a group. The current release supports HDFS-backed groups and locally configured groups.

Privilege Object
INSERT DB, TABLE
SELECT SERVER, DB, TABLE, COLUMN
UPDATE COLLECTION, CONFIG
QUERY COLLECTION, CONFIG
ALL SERVER, TABLE, DB, URI, COLLECTION, CONFIG

Sentry权限模型：

Sentry使用基于角色权限模型，有如下特征

1、允许所有用户执行show functions，show locks等

2、允许用户看到那些有权限的tables,databases,collections，configs等

3、HiveQL执行例如LOAD，IMPORT等操作，需要用户有相应URI的权限

4、赋予一个URI某个权限，其子目录也递归赋予这个权限，所以只需将权限grant给一个父目录

5、CDH 5.5引入Column级别的访问控制，之前版本的如果要控制到列级别访问，使用View，创建一个只包含有访问权限Column的View

Tips

    Hive中使用Sentry的时候，必须使用Beeline方式执行查询，Hive Cli方式不支持Sentry



Hive On Sentry中Object层级结构关系

权限能够赋予层级中的不同的object，一个权限如果赋予层级中一个object，则这个object子层级中的object继承这个权限。

比如赋予DATABASE的SELECT权限给用户A，则用户A拥有DATABASE下所有Object的SELECT权限

wKioL1mTwyGgdoqjAAAL7oOGnWc408.png

权限类型和Object的对应关系

Privilege Object
INSERT DB, TABLE
SELECT DB, TABLE, VIEW, COLUMN
ALL SERVER, TABLE, DB, URI

权限层级

Base Object Granular privileges on object Container object that contains the base object Privileges on container object that implies privileges on the base object
DATABASE ALL SERVER ALL
TABLE INSERT DATABASE ALL
TABLE SELECT DATABASE ALL
COLUMN SELECT DATABASE ALL
VIEW SELECT DATABASE ALL

Hive&Impala操作权限表

Operation Scope Privileges Required URI
CREATE DATABASE SERVER ALL
DROP DATABASE DATABASE ALL
CREATE TABLE DATABASE ALL
DROP TABLE TABLE ALL
CREATE VIEW-This operation is allowed if you have column-level SELECTaccess to the columns being used. DATABASE; SELECT on TABLE; ALL
ALTER VIEW-This operation is allowed if you have column-level SELECTaccess to the columns being used. VIEW/TABLE ALL
DROP VIEW VIEW/TABLE ALL
ALTER TABLE .. ADD COLUMNS TABLE ALL
ALTER TABLE .. REPLACE COLUMNS TABLE ALL
ALTER TABLE .. CHANGE column TABLE ALL
ALTER TABLE .. RENAME TABLE ALL
ALTER TABLE .. SET TBLPROPERTIES TABLE ALL
ALTER TABLE .. SET FILEFORMAT TABLE ALL
ALTER TABLE .. SET LOCATION TABLE ALL URI
ALTER TABLE .. ADD PARTITION TABLE ALL
ALTER TABLE .. ADD PARTITION location TABLE ALL URI
ALTER TABLE .. DROP PARTITION TABLE ALL
ALTER TABLE .. PARTITION SET FILEFORMAT TABLE ALL
SHOW CREATE TABLE TABLE SELECT/INSERT
SHOW PARTITIONS TABLE SELECT/INSERT
SHOW TABLES-Output includes all the tables for which the user has table-level privileges and all the tables for which the user has some column-level privileges. TABLE SELECT/INSERT
SHOW GRANT ROLE-Output includes an additional field for any column-level privileges. TABLE SELECT/INSERT
DESCRIBE TABLE-Output shows all columns if the user has table level-privileges or SELECT privilege on at least one table column TABLE SELECT/INSERT
LOAD DATA TABLE INSERT URI
SELECT-You can grant the SELECT privilege on a view to give users access to specific columns of a table they do not otherwise have access to.
-See Column-level Authorization for details on allowed column-level operations.		 VIEW/TABLE; COLUMN SELECT
INSERT OVERWRITE TABLE TABLE INSERT
CREATE TABLE .. AS SELECT-This operation is allowed if you have column-level SELECTaccess to the columns being used. DATABASE; SELECT on TABLE ALL
USE <dbName> Any

CREATE FUNCTION SERVER ALL
ALTER TABLE .. SET SERDEPROPERTIES TABLE ALL
ALTER TABLE .. PARTITION SET SERDEPROPERTIES TABLE ALL
Hive-Only Operations
INSERT OVERWRITE DIRECTORY TABLE INSERT URI
Analyze TABLE TABLE SELECT + INSERT
IMPORT TABLE DATABASE ALL URI
EXPORT TABLE TABLE SELECT URI
ALTER TABLE TOUCH TABLE ALL
ALTER TABLE TOUCH PARTITION TABLE ALL
ALTER TABLE .. CLUSTERED BY SORTED BY TABLE ALL
ALTER TABLE .. ENABLE/DISABLE TABLE ALL
ALTER TABLE .. PARTITION ENABLE/DISABLE TABLE ALL
ALTER TABLE .. PARTITION.. RENAME TO PARTITION TABLE ALL
MSCK REPAIR TABLE TABLE ALL
ALTER DATABASE DATABASE ALL
DESCRIBE DATABASE DATABASE SELECT/INSERT
SHOW COLUMNS-Output for this operation filters columns to which the user does not have explicit SELECT access TABLE SELECT/INSERT
CREATE INDEX TABLE ALL
DROP INDEX TABLE ALL
SHOW INDEXES TABLE SELECT/INSERT
GRANT PRIVILEGE Allowed only for Sentry admin users

REVOKE PRIVILEGE Allowed only for Sentry admin users

SHOW GRANT Allowed only for Sentry admin users

SHOW TBLPROPERTIES TABLE SELECT/INSERT
DESCRIBE TABLE .. PARTITION TABLE SELECT/INSERT
ADD JAR Not Allowed

ADD FILE Not Allowed

DFS Not Allowed

Impala-Only Operations
EXPLAIN TABLE; COLUMN SELECT
INVALIDATE METADATA SERVER ALL
INVALIDATE METADATA <table name> TABLE SELECT/INSERT
REFRESH <table name> or REFRESH <table name> PARTITION (<partition_spec>) TABLE SELECT/INSERT
DROP FUNCTION SERVER ALL
COMPUTE STATS TABLE ALL



通过HUE管理Sentry:http://10120275.blog.51cto.com/10110275/1956777