HPE Ezmeral Data Fabric 6.2 is In Maintenance and transitions to "End of Maintenance" in June 2024. Please see the latest documentation.

About Release 6.2
This site contains documentation for HPE Ezmeral Data Fabric release 6.2 including installation, configuration, administration, and reference content, as well as content for the associated bundled ecosystem components and drivers.
6.2 Installation
This section contains information about installing and upgrading HPE Ezmeral Data Fabric software. It also contains information about how to migrate data and applications from an Apache Hadoop cluster to a HPE Ezmeral Data Fabric cluster.
6.2 Data Fabric
HPE Ezmeral Data Fabric is the industry-leading data platform for AI and analytics that solves enterprise business needs.
6.2 Administration
This section describes how to manage the nodes and services that make up a cluster.
- Administering Users and Clusters
  Lists topics that help manage a data-fabric cluster.
- Administering Nodes
  Provides a synopsis of managing nodes in a cluster.
  - Managing Nodes
    Describes the Nodes page on the Control System.
    - Viewing the list of Nodes
      Explains how to view the list of Nodes using either the Control System or the CLI.
    - Monitoring Nodes
      Explains how to monitor nodes using either the Control System or the CLI.
    - Gathering Node Metrics
      Explains how to gather node metrics using the CLI.
    - Viewing Node Details
      Describes how to view node details using either the Control System or the CLI.
    - Setting Up Node Topology
      Define node topologies for every node in the cluster.
    - Adding Nodes to a Cluster
      Describes how to add nodes to a cluster.
    - Removing Nodes from a Cluster
      Provides an overview of how to remove nodes from a cluster.
    - Reconfiguring a Node from the Command-Line
      Provides an overview of the procedure to reconfigure a node using the CLI.
    - Renaming a Node from the Command-Line
      Provides distribution-specific instructions for renaming a node.
    - Changing the IP Address of a Node
      Describes how to change the IP address of any node in the cluster using the CLI.
    - Viewing Active Node Alarms
      Describes how to view active node alarms using the Control System and the CLI.
    - Allocating Memory for Nodes
      Describes how the Warden allocates memory for nodes.
    - Performing Maintenance on a Node from the Command-Line
      Describes how to maintain the performance of a node using the CLI.
      - Putting a Node into Maintenance Mode
        Describes how to put a node into maintenance mode.
      - Taking a Node Out of Maintenance Mode
        Describes how to bring a node back online from maintenance mode.
  - Managing Roles
    Describes how to manage roles on a node.
  - Managing Services
    Synopsis on managing services.
  - Managing Disks
    Provides a brief overview of adding and removing disks from the HPE Ezmeral Data Fabric file system.
- Administering Volumes
  This section provide information about how to organize and manage data using volumes, a unique feature of HPE Ezmeral Data Fabric clusters.
- Administering Files and Directories
- Administering Tables
  Administration of the HPE Ezmeral Data Fabric Database is done primarily via the command line (maprcli) or with the Managed Control System (MCS). Regardless of whether the HPE Ezmeral Data Fabric Database table is used for binary files or JSON documents, the same types of commands are used with slightly different parameter options. HPE Ezmeral Data Fabric Database administration is associated with tables, columns and column families, and table regions.
- Administering Streams
- Administering Data Fabric Gateways
  A HPE Ezmeral Data Fabric gateway mediates one-way communication between a source HPE Ezmeral Data Fabric cluster and a destination cluster. You can replicate HPE Ezmeral Data Fabric Database tables (binary and JSON) and HPE Ezmeral Data Fabric Streams streams. HPE Ezmeral Data Fabric 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 security and manage secure clusters.
- Managing Secure Clusters
  Provides procedures that will enable you to use MapR clusters securely.
- Administering the Data Access Gateway
  The HPE Ezmeral Data Fabric Data Access Gateway is a service that acts as a proxy and gateway for translating requests between lightweight client applications and the HPE Ezmeral Data Fabric 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
  Lists the common errors and their solutions.
- Best Practices for Backing Up HPE Ezmeral Data Fabric Information
  Lists the best practices and performance considerations to follow when backing up HPE Ezmeral Data Fabric information.
6.2 Development
This section contains information related to application development for Ezmeral ecosystem components and HPE Ezmeral Data Fabric products, including the file system, Database (Key-Value and JSON), and Event Streams.
Other Docs
This section contains release-independent information, including: Installer documentation, Ecosystem release notes, interoperability matrices, security vulnerabilities, and links to other data-fabric version documentation.
Glossary
Definitions for commonly used terms in MapR Converged Data Platform environments.

Putting a Node into Maintenance Mode

Describes how to put a node into maintenance mode.

About this task

If you put a node into maintenance mode, the node is marked unserviceable, but is still attached to the cluster.

Before putting a node into maintenance mode, ensure that:

All copies of the CLDB volume exist if the node is a CLDB node. You cannot put a CLDB master into maintenance mode until the CLDB service is stopped. You can shut down the CLDB service only if the CLDB is a secondary CLDB or you have enabled high availability for CLDB.
You cannot put a node into maintenance mode if the node is running as the CLDB master and also supporting file-system services.
All running processing tasks (NodeManager and Spark, for example) that depend on the file system have been stopped.

WARNING Do not put a node under maintenance if there are any volume under-replicated alarms because doing so might take some data completely offline.

To put a node into maintenance mode, perform the following actions:

Procedure

From a terminal, issue the node maintenance command:
```
/opt/mapr/bin/maprcli node maintenance -nodes <IP|hostname> -timeoutminutes <minutes>
```
If you run this command, specify a timeout (in minutes) long enough for you to perform necessary maintenance on the node.

NOTE For the duration of the timeout, the cluster CLDB considers this node as unavailable. Under this scenario, the CLDB does not trigger data replication for this node until it exits maintenance mode. Furthermore, clients accessing containers on the node receive the appropriate error and retry other container copies. Note also that if a node is put under maintenance for more than five minutes, the file system shuts down on that node to prevent any other operations from occurring. This value of five minutes is hard-coded and cannot be changed. Even if you reboot the node, the maintenance mode persists until the timeout is reached.
Stop Warden on the node:
```
service mapr-warden stop
```
To bring the node back online, see Taking a Node Out of Maintenance Mode.