Understanding Cloudera Hadoop users

Step 1: A number of special users are created by default when installing and using CDH and Cloudera Manager. For example

Unix user id: hdfs
groups: hdfs hadoop

Unix user id: spark
groups: spark

Unix user id: hive
groups: hive

and so on.

Cloudera Manager

The Cloudera manager processes will use the Unix Id of “cloudera-scm” and group of “cloudera-scm”. Cloudera Manager Server runs as a central server which hosts the UI Web Server and the application logic for managing CDH (i.e. Cloudera Distribution including Hadoop). Everything related to installing CDH, configuring services, and starting and stopping services is managed by the Cloudera Manager Server.

The Cloudera Manager Agents are installed on every managed host. They are responsible for starting and stopping Linux processes, unpacking configurations, triggering various installation paths, and monitoring the host.

Unix Terminal on VMWare

Open a command-line by clicking on the terminal window icon or via “Applications –> System Tools –> Terminal”

The default user is “cloudera

You can list the “groups” as shown below:

or as

Switch to “root” user with

Switch back to “cloudera” user with

Step 2: You can list HDFS files as

You can recursively list all the files in HDFS recursively as a “cloudera” user as shown below:

Step 3: Go to Hue UI via a web browser, and go to “Files” and inspect the HDFS folders and users in the “/users” folder as shown below.

HDFS folders with user, group, and permissions

You can change permissions by selecting a folder and then picking the drop down “Actions” followed by “Change permissions“.

Step 4: Superusers are defined by a group named in hdfs-site.xml, “dfs.permissions.superusergroup“, which is the UNIX group containing users that will be treated as superusers by HDFS. The default is supergroup if installing with Cloudera Manager, and can be changed in the “Cloudera Manager UI” as shown below.

Cloudera supergroup setting


BigData on Cloudera
Module 1 Installing & getting started with Cloudera Quick Start-
Unit 1 Installing & getting started with Cloudera QuickStart on VMWare for windows in 17 steps  - Preview
Unit 2 ⏯ Cloudera Hue, Terminal Window (on edge node) & Cloudera Manager overview  - Preview
Unit 3 Understanding Cloudera Hadoop users  - Preview
Unit 4 Upgrading Java version to JDK 8 in Cloudera Quickstart  - Preview
Module 2 Getting started with HDFS on Cloudera+
Unit 1 ⏯ Hue and terminal window to work with HDFS  - Preview
Unit 2 Java program to list files in HDFS & write to HDFS using Hadoop API  - Preview
Unit 3 ⏯ Java program to list files on HDFS & write to a file in HDFS  - Preview
Unit 4 Write to & Read from a csv file in HDFS using Java & Hadoop API  - Preview
Unit 5 ⏯ Write to & read from HDFS using Hadoop API in Java  - Preview
Module 3 Running an Apache Spark job on Cloudera+
Unit 1 Before running a Spark job on a YARN cluster in Cloudera  - Preview
Unit 2 Running a Spark job on YARN cluster in Cloudera  - Preview
Unit 3 ⏯ Running a Spark job on YARN cluster  - Preview
Unit 4 Write to HDFS from Spark in YARN mode & local mode  - Preview
Unit 5 ⏯ Write to HDFS from Spark in YARN & local modes  - Preview
Unit 6 Spark running on YARN and Local modes reading from HDFS  - Preview
Unit 7 ⏯ Spark running on YARN and Local modes reading from HDFS  - Preview
Module 4 Hive on Cloudera+
Unit 1 Getting started with Hive  - Preview
Unit 2 ⏯ Getting started with Hive  - Preview
Module 5 HBase on Cloudera+
Unit 1 Write to HBase from Java  - Preview
Unit 2 Read from HBase in Java  - Preview
Unit 3 HBase shell commands to get, scan, and delete  - Preview
Unit 4 ⏯ Write to & read from HBase  - Preview
Module 6 Writing to & reading from Avro in Spark+
Unit 1 Write to an Avro file from a Spark job in local mode  - Preview
Unit 2 Read an Avro file from HDFS via a Spark job running in local mode  - Preview
Unit 3 ⏯ Write to & read from an Avro file on HDFS using Spark  - Preview
Unit 4 Write to HDFS as Avro from a Spark job using Avro IDL  - Preview
Unit 5 ⏯ Write to Avro using Avro IDL from a Spark job  - Preview
Unit 6 Create a Hive table over Avro data  - Preview
Unit 7 ⏯ Hive table over an Avro folder & avro-tools to generate the schema  - Preview
Module 7 Writing to & reading from Parquet in Spark+
Unit 1 Write to a Parquet file from a Spark job in local mode  - Preview
Unit 2 Read from a Parquet file in a Spark job running in local mode  - Preview
Unit 3 ⏯ Write to and read from Parquet data on HDFS via Spark  - Preview
Unit 4 Create a Hive table over Parquet data  - Preview
Unit 5 ⏯ Hive over Parquet data  - Preview
Module 8 Spark SQL+
Unit 1 Spark SQL read a Hive table  - Preview
Unit 2 Write to Parquet using Spark SQL & Dataframe  - Preview
Unit 3 Read from Parquet with Spark SQL & Dataframe  - Preview
Unit 4 ⏯ Spark SQL basics video tutorial  - Preview
Module 9 Spark streaming+
Unit 1 Spark streaming text files  - Preview
Unit 2 Spark file streaming in Java  - Preview
Unit 3 ⏯ Spark streaming video tutorial  - Preview
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