Managing HBase | 6.3.x | Cloudera Documentation (2023)

Gracefully Shutting Down an HBase RegionServer

1. Go to the HBase service.
2. Click the Instances tab.
3. From the list of Role Instances, select the RegionServer you want to shut down gracefully.
4. Select Actions for Selected > Decommission (Graceful Stop).
5. Cloudera Manager attempts to gracefully shut down the RegionServer for the interval configured in the Graceful Shutdown Timeout configuration option, which defaults to 3 minutes. If the gracefulshutdown fails, Cloudera Manager forcibly stops the process by sending a SIGKILL (kill -9) signal. HBase will perform recovery actions onregions that were on the forcibly stopped RegionServer.
6. If you cancel the graceful shutdown before the Graceful Shutdown Timeout expires, you can still manually stop a RegionServer by selecting Actions for Selected > Stop, which sends a SIGTERM (kill -5) signal.

Gracefully Shutting Down the HBase Service

1. Go to the HBase service.
2. Select Actions > Stop. This tries to perform an HBase Master-driven gracefulshutdown for the length of the configured Graceful Shutdown Timeout (three minutes by default), after which it abruptly shuts down the whole service.

Configuring the Graceful Shutdown Timeout Property

Minimum Required Role: Configurator (also provided by Cluster Administrator, Full Administrator)

This timeout only affects a graceful shutdown of the entire HBase service, not individual RegionServers. Therefore, if you have a large cluster with many RegionServers, you shouldstrongly consider increasing the timeout from its default of 180 seconds.

1. Go to the HBase service.
2. Click the Configuration tab.
3. Select Scope > HBASE-1 (Service Wide)
4. Use the Search box to search for the Graceful Shutdown Timeout property and edit the value.
5. Click Save Changes to save this setting.

The Thrift Server role is not added by default when you install HBase, but it is required before you can use certain other features such as theHue HBase browser. To add the Thrift Server role:

1. Go to the HBase service.
2. Click the Instances tab.
3. Click the Add Role Instances button.
4. Select the host(s) where you want to add the Thrift Server role (you only need one for Hue) and click Continue. The Thrift Server role should appearin the instances list for the HBase server.
5. Select the Thrift Server role instance.
6. Select Actions for Selected > Start.

The HBase coprocessor framework provides a way to extend HBase with custom functionality. To configure these properties in Cloudera Manager:

1. Select the HBase service.
2. Click the Configuration tab.
3. Select Scope > All.
4. Select Category > All.
5. Type HBase Coprocessor in the Search box.
6. You can configure the values of the following properties:
   • HBase Coprocessor Abort on Error (Service-Wide)
   • HBase Coprocessor Master Classes (Master Default Group)
   • HBase Coprocessor Region Classes (RegionServer Default Group)
7. Enter a Reason for change, and then click Save Changes to commit the changes.

In CDH 5.7 and higher, you can disable loading of system (HBase-wide) or user (table-wide) coprocessors. Cloudera recommends against disabling loading of system coprocessors, becauseHBase security functionality is implemented using system coprocessors. However, disabling loading of user coprocessors may be appropriate.

1. Select the HBase service.
2. Click the Configuration tab.
3. Search for HBase Service Advanced Configuration Snippet (Safety Valve) for hbase-site.xml.
4. To disable loading of all coprocessors, add a new property with the name hbase.coprocessor.enabled and set its value to false. Cloudera does not recommend this setting.
5. To disable loading of user coprocessors, add a new property with the name hbase.coprocessor.user.enabled and set its value to false.
6. Enter a Reason for change, and then click Save Changes to commit the changes.

1. Go to the HBase service.
2. Click the Configuration tab.
3. Select Scope > HBASE-1 (Service-Wide).
4. Select Category > Performance.
5. Configure the HDFS Hedged Read Threadpool Size and HDFS Hedged Read Delay Threshold properties. The descriptions foreach of these properties on the configuration pages provide more information.
6. Enter a Reason for change, and then click Save Changes to commit the changes.

HBase includes several advanced configuration parameters for adjusting the number of threads available to service flushes and compactions in the presence of write-heavy workloads.Tuning these parameters incorrectly can severely degrade performance and is not necessary for most HBase clusters. If you use Cloudera Manager, configure these options using the HBase Service Advanced Configuration Snippet (Safety Valve) for hbase-site.xml.

hbase.hstore.flusher.count

The number of threads available to flush writes from memory to disk. Never increase hbase.hstore.flusher.count to more of 50% of the number of disksavailable to HBase. For example, if you have 8 solid-state drives (SSDs), hbase.hstore.flusher.count should never exceed 4. This allows scanners and compactions toproceed even in the presence of very high writes.

hbase.regionserver.thread.compaction.large and hbase.regionserver.thread.compaction.small

The number of threads available to handle small and large compactions, respectively. Never increase either of these options to more than 50% of the number of disks available toHBase.

Ideally, hbase.regionserver.thread.compaction.small should be greater than or equal to hbase.regionserver.thread.compaction.large, since the large compaction threads do more intense work and will be in use longer for a given operation.