1. Defining Service Users and Groups for a HDP 2.x Stack

The individual services in Hadoop run under the ownership of their respective Unix accounts. These accounts are known as service users. These service users belong to a special Unix group. "Smoke Test" is a service user dedicated specifically for running smoke tests on components during installation using the Services View of the Ambari Web GUI. You can also run service checks as the "Smoke Test" user on-demand after installation. You can customize any of these users and groups using the Misc tab during the Customize Services installation step.

[Note]Note

Use the Skip Group Modifications option to not modify the Linux groups in the cluster. Choosing this option is typically required if your environment manages groups using LDAP and not on the local Linux machines.

If you choose to customize names, Ambari checks to see if these custom accounts already exist. If they do not exist, Ambari creates them. The default accounts are always created during installation whether or not custom accounts are specified. These default accounts are not used and can be removed post-install.

[Note]Note

All new service user accounts, and any existing user accounts used as service users, must have a UID >= 1000.

Service Users

Service*

Component

Default User Account

Accumulo

Accumulo Tracer, Accumulo Monitor, Accumulo GC, Accumulo Master

accumulo (HDP 2.2 and 2.3 Stack)

Ambari Metrics

Metrics Collector, Metrics Monitor

ams

Atlas

Atlas Metadata Server

atlas (HDP 2.3 Stack)

Falcon

Falcon Server

falcon (HDP 2.1, 2.2 and 2.3 Stack)

Flume

Flume Agents

flume

HBase

MasterServer RegionServer

hbase

HDFS

NameNode SecondaryNameNode DataNode

hdfs

Hive

Hive Metastore, HiveServer2

hive

Kafka

Kafka Broker

kafka

Knox

Knox Gateway

knox

Mahout

Mahout clients

mahout (HDP 2.2 and 2.3 Stack)

MapReduce2

HistoryServer

mapred

Oozie

Oozie Server

oozie

PostgreSQL

PostgreSQL (with Ambari Server)

postgres (Created as part of installing the default PostgreSQL database with Ambari Server. If you are not using the Ambari PostgreSQL database, this user is not needed.)

Ranger

Ranger Admin, Ranger Usersync

ranger (Ranger is available with HDP 2.2 Stack)

Ranger KMS

Ranger KMS Server

kms (HDP 2.3 Stack)

Spark

Spark History Server

spark (Spark is available with HDP 2.2 Stack)

Sqoop

Sqoop

sqoop

Storm

Masters (Nimbus, DRPC Server, Storm REST API, Server, Storm UI Server) Slaves (Supervisors, Logviewers)

storm (HDP 2.1, 2.2 and 2.3 Stack)

Tez

Tez clients

tez (HDP 2.1, 2.2 and 2.3 Stack)

WebHCat

WebHCat Server

hcat

YARN

NodeManager ResourceManager

yarn

ZooKeeper

ZooKeeper

zookeeper

*For all components, the Smoke Test user performs smoke tests against cluster services as part of the install process. It also can perform these on-demand, from the Ambari Web UI. The default user account for the smoke test user is ambari-qa.

Service Groups

Service

Components

Default Group Account

All

All

hadoop

Atlas

Atlas Metadata Server

atlas

Knox

Knox Gateway

knox

Ranger

Ranger Admin, Ranger Usersync

ranger

Ranger KMS

Ranger KMS Server

kms

Spark

Spark History Server

spark


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