6.0 Administration
This section describes how to manage the nodes and services that make up a cluster.
- Administering Users and Clusters
  - Managing Users and Groups
  - Managing the Cluster
    - Managing Auditing
      Provides instructions for using MapR auditing features.
    - Configuring Balancer Settings
    - Managing Licenses
    - Setting Quota Defaults for Users and Groups
    - Specifying the Location of Gateways
    - Managing Alarms
    - Working with Multiple Instances of the MapR-FS
      The Multi-MapR-FS feature allows multiple instances of the file server to run on a single node in a single process.
    - Converting a Cluster from Root to Non-Root User from the Command-Line
    - Starting Up a Cluster
    - Shutting Down a Cluster
    - Managing Another Unsecure Cluster Using MCS
    - Allocating Cluster Resource from the Command-Line
- Administering Nodes
- Administering Volumes
  This section provide information about how to organize and manage data using volumes, a unique feature of MapR clusters.
- Administering Files and Directories
- Administering Tables
  Administration of the MapR-DB is done primarily via the command line (maprcli) or with the MapR Control System (MCS). Regardless of whether the MapR-DB table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. MapR-DB administration is associated with tables, columns and column families, and table regions.
- Administering Streams
- Administering MapR Gateways
  A MapR gateway mediates one-way communication between a source MapR cluster and a destination cluster. You can replicate MapR-DB tables (binary and JSON) and MapR-ES streams. MapR gateways also apply updates from JSON tables to their secondary indexes and propagate Change Data Capture (CDC) logs.
- Administering Services
- Monitoring the Cluster
  This section describes how to monitor the health and performance of a MapR cluster.
- Configuring Security
  Describes how to configure MapR security and manage secure clusters.
- Managing Secure Clusters
  Provides procedures that will enable you to use MapR clusters securely.
- Administering the MapR Data Access Gateway
  The MapR Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the MapR cluster. This section describes considerations when upgrading the service, how to modify configuration settings, and how to administer and manage the service.
- Planning for High Availability
- Administrator's Reference
  This section contains in-depth reference information for the administrator.
- Troubleshooting Cluster Administration
- Best Practices for Backing Up MapR Information

Allocating Cluster Resource from the Command-Line

In a MapR Hadoop cluster, warden sets the default resource allocation for the operating system, MapR-FS, MapR Hadoop services, and YARN applications. Warden allocates resources to MapR Hadoop services and applications based on the roles installed on a node. For example, warden allocates resources for YARN applications on nodes with NodeManager role installed.

In general, you should not need to override the values set in the default configuration files and by warden. However, users can provide updated values by adding or updating parameters in the Hadoop site configuration files or warden files. To override parameter values for a single job, the option can be overridden in the command line when submitting a YARN application to the cluster.

To determine the current value of a hadoop parameter, run hadoop conf | grep <ParameterName>. In the following example, the hadoop conf command was used to get the value of mapreduce.map.memory.md:

# hadoop conf | grep mapreduce.map.memory.mb
<property><name>mapreduce.map.memory.mb</name><value>1024</value><source>mapred-site.xml</source></property>

Alternatively, run hadoop conf without the grep command to get a full list of the current parameter values. To determine the current value of a warden parameter, open the warden files located in the following directories: /opt/mapr/conf/conf.d and /opt/mapr/conf.

NOTE: In some cases, the current value of the parameter can only be seen in the MCS or in ResourceManager.

Refer to Allocating Memory for Nodes to allocate memory and resources in a MapR cluster.