~~ Licensed under the Apache License, Version 2.0 (the "License"); ~~ you may not use this file except in compliance with the License. ~~ You may obtain a copy of the License at ~~ ~~ http://www.apache.org/licenses/LICENSE-2.0 ~~ ~~ Unless required by applicable law or agreed to in writing, software ~~ distributed under the License is distributed on an "AS IS" BASIS, ~~ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. ~~ See the License for the specific language governing permissions and ~~ limitations under the License. See accompanying LICENSE file. --- Service Level Authorization Guide --- --- ${maven.build.timestamp} Service Level Authorization Guide %{toc|section=1|fromDepth=0} * Purpose This document describes how to configure and manage Service Level Authorization for Hadoop. * Prerequisites Make sure Hadoop is installed, configured and setup correctly. For more information see: * {{{./SingleCluster.html}Single Node Setup}} for first-time users. * {{{./ClusterSetup.html}Cluster Setup}} for large, distributed clusters. * Overview Service Level Authorization is the initial authorization mechanism to ensure clients connecting to a particular Hadoop service have the necessary, pre-configured, permissions and are authorized to access the given service. For example, a MapReduce cluster can use this mechanism to allow a configured list of users/groups to submit jobs. The <<<${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. * Configuration 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. *-------------------------------------+--------------------------------------+ security.ha.service.protocol.acl | ACL for HAService protocol used by HAAdmin to manage the active and stand-by states of namenode. *-------------------------------------+--------------------------------------+ ** Access Control Lists <<<${HADOOP_CONF_DIR}/hadoop-policy.xml>>> defines an access control list for each Hadoop service. Every access control list has a simple format: The list of users and groups are both comma separated list of names. The two lists are separated by a space. Example: <<>>. Add a blank at the beginning of the line if only a list of groups is to be provided, equivalently a comma-separated list of users followed by a space or nothing implies only a set of given users. A special value of <<<*>>> implies that all users are allowed to access the service. If access control list is not defined for a service, the value of <<>> is applied. If <<>> is not defined, <<<*>>> is applied. ** Blocked Access Control Lists In some cases, it is required to specify blocked access control list for a service. This specifies the list of users and groups who are not authorized to access the service. The format of the blocked access control list is same as that of access control list. The blocked access control list can be specified via <<<${HADOOP_CONF_DIR}/hadoop-policy.xml>>>. The property name is derived by suffixing with ".blocked". Example: The property name of blocked access control list for <<> will be <<>> For a service, it is possible to specify both an access control list and a blocked control list. A user is authorized to access the service if the user is in the access control and not in the blocked access control list. If blocked access control list is not defined for a service, the value of <<>> is applied. If <<>> is not defined, empty blocked access control list is applied. ** 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 <<>> and <<>> 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 <<>> 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. ** Examples Allow only users <<>>, <<>> and users in the <<>> group to submit jobs to the MapReduce cluster: ---- security.job.submission.protocol.acl alice,bob mapreduce ---- Allow only DataNodes running as the users who belong to the group datanodes to communicate with the NameNode: ---- security.datanode.protocol.acl datanodes ---- Allow any user to talk to the HDFS cluster as a DFSClient: ---- security.client.protocol.acl * ----