About Release 7.9.0
This site contains documentation for HPE Ezmeral Data Fabric release 7.9.0, including installation, configuration, administration, and reference content, as well as content for the associated ecosystem components and drivers.
7.9.0 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.
7.9.0 Data Fabric
HPE Ezmeral Data Fabric is the industry-leading data platform for AI and analytics that solves enterprise business needs.
7.9.0 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.
  - Managing Roles
    Describes how to manage roles on a node.
    - Adding Roles to a Node
      Summarizes the process to add a role.
    - Removing Roles from a Node
      Describes how to remove a role from a node.
      - Removing a Role
        Describes how to remove a role from a node, using the CLI.
      - Removing a CLDB Role
        Describes how to remove the CLDB role from a node.
      - Removing a ZooKeeper Role
        Describes how to remove the ZooKeeper role from a node by using the CLI.
      - Removing a Fileserver Role
        Describes how to remove the Fileserver role from a node.
    - Assigning Roles to Nodes for Best Performance
      Guidelines to optimise the cluster's service layout for best performance.
  - 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 Data Fabric 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.
- IPv6 Support in Data Fabric
  Describes the IPv6 support feature for Data Fabric.
7.9.0 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.

Removing a ZooKeeper Role

Describes how to remove the ZooKeeper role from a node by using the CLI.

About this task

This procedure removes one ZooKeeper node from a previously installed cluster and uses rolling restarts to avoid cluster outages. If multiple ZooKeeper instances need to be removed, repeat this procedure from start to finish for each such ZooKeeper.

While it is possible to use a modified version of this procedure to remove multiple ZooKeepers at once, doing so involves more complexity and carries increased risk of creating a cluster outage if incorrect steps are followed.

Procedure

On each node, identify the state of the ZooKeeper service:
```
/opt/mapr/initscripts/zookeeper qstatus
```
All previously installed ZooKeeper services, other than the one being removed, must be running and in either the leader or follower state. Do not proceed further if the ZooKeeper services are not in the expected state.
On the node being removed, run the following command to stop ZooKeeper:
```
service mapr-zookeeper stop
```
On the node being removed, purge the mapr-zookeeper package.
On all nodes in the cluster, run configure.sh with the following options:
1. -Z: Specify all existing ZooKeeper nodes except the one being removed.
2. -R: Specify this option to use all previously set configurations.
For example:
```
/opt/mapr/server/configure.sh -Z <all-nodes-excluding-removed-one> -R
```
To identify the list of current ZooKeeper nodes in the cluster, run maprcli node listzookeepers.
On the remaining nodes, perform a rolling restart of the ZooKeeper services. Use the following command to restart the ZooKeeper services:
```
systemctl restart mapr-zookeeper
```
For each remaining ZooKeeper node, one by one, restart the ZooKeeper service and then wait until its state is shown as either leader or follower before proceeding to the next node:
Perform a rolling restart of Warden. On all nodes, run the following command to restart Warden:
```
systemctl restart mapr-warden
```
Run maprcli node listzookeepers. The output should show only the remaining ZooKeeper nodes.

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HPE Ezmeral Data Fabric – Customer-Managed 7.9.0 Documentation
Abstract	This site contains documentation for the customer-managed platform of the HPE Ezmeral Data Fabric version 7.9.0 including installation, configuration, administration, and reference content, as well as content for the associated bundled ecosystem components and drivers.
Published	November 2024
Edition	7.9.0