Apache > Hadoop > Core

Service Level Authorization Guide


This document describes how to configure and manage Service Level Authorization for Hadoop.


Ensure that Hadoop is installed, configured and setup correctly. More details:


Service Level Authorization is the initial authorization mechanism to ensure clients connecting to a particular Hadoop service have the necessary, pre-configured, permissions and are authorized to access the given service. For e.g. a Map/Reduce cluster can use this mechanism to allow a configured list of users/groups to submit jobs.

The ${HADOOP_CONF_DIR}/hadoop-policy.xml configuration file is used to define the access control lists for various Hadoop services.

Service Level Authorization is performed much before to other access control checks such as file-permission checks, access control on job queues etc.


This section describes how to configure service-level authorization via the configuration file {HADOOP_CONF_DIR}/hadoop-policy.xml.

Enable Service Level Authorization

By default, service-level authorization is disabled for Hadoop. To enable it set the configuration property hadoop.security.authorization to true in ${HADOOP_CONF_DIR}/core-site.xml.

Hadoop Services and Configuration Properties

This section lists the various Hadoop services and their configuration knobs:

Property Service
security.client.protocol.acl ACL for ClientProtocol, which is used by user code via the DistributedFileSystem.
security.client.datanode.protocol.acl ACL for ClientDatanodeProtocol, the client-to-datanode protocol for block recovery.
security.datanode.protocol.acl ACL for DatanodeProtocol, which is used by datanodes to communicate with the namenode.
security.inter.datanode.protocol.acl ACL for InterDatanodeProtocol, the inter-datanode protocol for updating generation timestamp.
security.namenode.protocol.acl ACL for NamenodeProtocol, the protocol used by the secondary namenode to communicate with the namenode.
security.inter.tracker.protocol.acl ACL for InterTrackerProtocol, used by the tasktrackers to communicate with the jobtracker.
security.job.submission.protocol.acl ACL for JobSubmissionProtocol, used by job clients to communciate with the jobtracker for job submission, querying job status etc.
security.task.umbilical.protocol.acl ACL for TaskUmbilicalProtocol, used by the map and reduce tasks to communicate with the parent tasktracker.
security.refresh.policy.protocol.acl ACL for RefreshAuthorizationPolicyProtocol, used by the dfsadmin and mradmin commands to refresh the security policy in-effect.

Access Control Lists

${HADOOP_CONF_DIR}/hadoop-policy.xml defines an access control list for each Hadoop service. Every access control list has a simple format:

The list of users and groups are both comma separated list of names. The two lists are separated by a space.

Example: user1,user2 group1,group2.

Add a blank at the beginning of the line if only a list of groups is to be provided, equivalently a comman-separated list of users followed by a space or nothing implies only a set of given users.

A special value of * implies that all users are allowed to access the service.

Refreshing Service Level Authorization Configuration

The service-level authorization configuration for the NameNode and JobTracker can be changed without restarting either of the Hadoop master daemons. The cluster administrator can change ${HADOOP_CONF_DIR}/hadoop-policy.xml on the master nodes and instruct the NameNode and JobTracker to reload their respective configurations via the -refreshServiceAcl switch to dfsadmin and mradmin commands respectively.

Refresh the service-level authorization configuration for the NameNode:

$ bin/hadoop dfsadmin -refreshServiceAcl

Refresh the service-level authorization configuration for the JobTracker:

$ bin/hadoop mradmin -refreshServiceAcl

Of course, one can use the security.refresh.policy.protocol.acl property in ${HADOOP_CONF_DIR}/hadoop-policy.xml to restrict access to the ability to refresh the service-level authorization configuration to certain users/groups.


Allow only users alice, bob and users in the mapreduce group to submit jobs to the Map/Reduce cluster:

    <value>alice,bob mapreduce</value>

Allow only DataNodes running as the users who belong to the group datanodes to communicate with the NameNode:

    <value> datanodes</value>

Allow any user to talk to the HDFS cluster as a DFSClient: