Because HBase depends on Hadoop, it bundles an instance of the Hadoop jar under its lib directory. The bundled jar is ONLY for use in standalone mode. In distributed mode, it is critical that the version of Hadoop that is out on your cluster match what is under HBase. Replace the hadoop jar found in the HBase lib directory with the hadoop jar you are running on your cluster to avoid version mismatch issues. Make sure you replace the jar in HBase everywhere on your cluster.
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Preface This is the official reference guide for the HBase version it ships with. Herein you will find either the definitive documentation on an HBase topic as of its standing when the referenced HBase version shipped, or it will point to the location in Javadoc or JIRA where the pertinent information can be found.
About This Guide This reference guide is a work in progress. Run mvn site to generate this documentation. Amendments and improvements to the documentation are welcomed.
Click this link to file a new documentation bug against Apache HBase with some values pre-selected. Contributing to the Documentation For an overview of AsciiDoc and suggestions to get started contributing to the documentation, see the relevant section later in this documentation. First off, distributed systems are hard; making a distributed system hum requires a disparate skillset that spans systems hardware and software and networking. You will also need to do a recalibration if up to this your computing has been bound to a single box.
Here is one good starting point: Fallacies of Distributed Computing. That said, you are welcome. Yours, the HBase Community. To protect existing HBase installations from new vulnerabilities, please do not use JIRA to report security-related bugs. Instead, send your report to the mailing list private hbase. Someone on that list will contact you to follow up on your report. In the interest of clarity, here is a brief explanation of what is generally meant by these phrases, in the context of HBase.
Commercial technical support for Apache HBase is provided by many Hadoop vendors. The Apache HBase team assumes no responsibility for your HBase clusters, your configuration, or your data.
If you think this designation should be reconsidered for a given feature or use pattern, file a JIRA or start a discussion on one of the mailing lists. It is an unknown, and there are no guarantees. Getting Started Quickstart will get you up and running on a single-node, standalone instance of HBase.
It is our most basic deploy profile. We will show you how to create a table in HBase using the hbase shell CLI, insert rows into the table, perform put and scan operations against the table, enable or disable the table, and start and stop HBase.
Apart from downloading HBase, this procedure should take less than 10 minutes. See Java for information about supported JDK versions. Click on the suggested top link. This will take you to a mirror of HBase Releases. Extract the downloaded file and change to the newly-created directory. First, locate the installation of java on your machine. On Unix systems, you can use the whereis java command. The java implementation to use.
At this time, you may consider changing the location on the local filesystem where HBase writes its application data and the data written by its embedded ZooKeeper instance. By default, HBase uses paths under hbase. Example 1.
Example hbase-site. When unconfigured, HBase uses hbase. Notable among them are hbase. This is most likely acceptable for local development and testing use cases. It is not appropriate for production deployments; eventually you will lose data. Instead, ensure your production deployment sets hbase.
Issue the command, and if all goes well, a message is logged to standard output showing that HBase started successfully. You can use the jps command to verify that you have one running process called HMaster. Java needs to be installed and available.
In this example, some usage and version information that is printed when you start HBase Shell has been omitted. Type help and press Enter, to display some basic usage information for HBase Shell, as well as several example commands. Notice that table names, rows, columns all must be enclosed in quote characters. Create a table.
Use the create command to create a new table. You must specify the table name and the ColumnFamily name. To put data into your table, use the put command. The first insert is at row1, column cf:a, with a value of value1. Columns in HBase are comprised of a column family prefix, cf in this example, followed by a colon and then a column qualifier suffix, a in this case.
Scan the table for all data at once. One of the ways to get data from HBase is to scan. Use the scan command to scan the table for data. You can limit your scan, but for now, all data is fetched. To get a single row of data at a time, use the get command. If you want to delete a table or change its settings, as well as in some other situations, you need to disable the table first, using the disable command. You can re-enable it using the enable command. To drop delete a table, use the drop command.
To exit the HBase Shell and disconnect from your cluster, use the quit command. HBase is still running in the background. The above has shown you how to start and stop a standalone instance of HBase.
In the next sections we give a quick overview of other modes of hbase deploy. Pseudo-Distributed Local Install After working your way through the quickstart using standalone mode, you can re-configure HBase to run in pseudo-distributed mode.
Previously in standalone mode , all these daemons ran in a single jvm process, and your data was stored under hbase. This is optional; you can skip the HDFS configuration to continue storing your data in the local filesystem. It also assumes you are using Hadoop 2. Stop HBase if it is running. If you have just finished quickstart and HBase is still running, stop it. This procedure will create a totally new directory where HBase will store its data, so any databases you created before will be lost.
Configure HBase. Edit the hbase-site. First, add the following property which directs HBase to run in distributed mode, with one JVM instance per daemon. In this example, HDFS is running on the localhost at port If you create the directory, HBase will attempt to do a migration, which is not what you want. Finally, remove the configuration for hbase.
Start HBase. If your system is configured correctly, the jps command should show the HMaster and HRegionServer processes running. You can use the HBase Shell to create a table, populate it with data, scan and get values from it, using the same procedure as in shell exercises. Running multiple HMaster instances on the same hardware does not make sense in a production environment, in the same way that running a pseudo-distributed cluster does not make sense for production.
This step is offered for testing and learning purposes only. The HMaster server controls the HBase cluster. You can start up to 9 backup HMaster servers, which makes 10 total HMasters, counting the primary.
To start a backup HMaster, use the local-master-backup. For each backup master you want to start, add a parameter representing the port offset for that master. Each HMaster uses two ports and by default. The port offset is added to these ports, so using an offset of 2, the backup HMaster would use ports and The only contents of the file is the PID.
You can use the kill -9 command to kill that PID. Generally, one HRegionServer runs per node in the cluster. Running multiple HRegionServers on the same system can be useful for testing in pseudo-distributed mode. The local-regionservers. It works in a similar way to the local-master-backup. Each RegionServer requires two ports, and the default ports are and Since HBase version 1.
With values and for base ports, 99 additional RegionServers can be supported, on a server. Advanced - Fully Distributed In reality, you need a fully-distributed configuration to fully test HBase and to use it in real-world scenarios. In a distributed configuration, the cluster contains multiple nodes, each of which runs one or more HBase daemon.
Preface This is the official reference guide for the HBase version it ships with. Herein you will find either the definitive documentation on an HBase topic as of its standing when the referenced HBase version shipped, or it will point to the location in Javadoc or JIRA where the pertinent information can be found. About This Guide This reference guide is a work in progress. Run mvn site to generate this documentation. Amendments and improvements to the documentation are welcomed. Click this link to file a new documentation bug against Apache HBase with some values pre-selected. Contributing to the Documentation For an overview of AsciiDoc and suggestions to get started contributing to the documentation, see the relevant section later in this documentation.
Apache HBase Guide
Drilling down You can drill down on a metric record by pressing i key in the top screen. With this feature, you can find hot regions easily in a top-down manner. Help screen You can see the help screen by pressing h key in the top screen. How hbtop gets the metrics data hbtop gets the metrics from ClusterMetrics which is returned as the result of a call to Admin getClusterMetrics on the current HMaster. To add metrics to hbtop, they will need to be exposed via ClusterMetrics.
Fix some issues with the HBase reference guide