[HBASE-6721] RegionServer Group based Assignment

• Type: New Feature
• Status: Closed
• Priority: Major
• Resolution: Fixed
• Fix Version/s: 2.0.0
• Component/s: regionserver
• Labels: hbase-6721
• Hadoop Flags: Reviewed

Release Note

[ADVANCED USERS ONLY] This patch adds a new experimental module hbase-rsgroup. It is an advanced feature for partitioning regionservers into distinctive groups for strict isolation, and should only be used by users who are sophisticated enough to understand the full implications and have a sufficient background in managing HBase clusters.

RSGroups can be defined and managed with shell commands or corresponding Java APIs. A server can be added to a group with hostname and port pair, and tables can be moved to this group so that only regionservers in the same rsgroup can host the regions of the table. RegionServers and tables can only belong to 1 group at a time. By default, all tables and regionservers belong to the "default" group. System tables can also be put into a group using the regular APIs. A custom balancer implementation tracks assignments per rsgroup and makes sure to move regions to the relevant regionservers in that group. The group information is stored in a regular HBase table, and a zookeeper-based read-only cache is used at the cluster bootstrap time.

To enable, add the following to your hbase-site.xml and restart your Master:


 <property>
   <name>hbase.coprocessor.master.classes</name>
   <value>org.apache.hadoop.hbase.rsgroup.RSGroupAdminEndpoint</value>
 </property>
 <property>
   <name>hbase.master.loadbalancer.class</name>
   <value>org.apache.hadoop.hbase.rsgroup.RSGroupBasedLoadBalancer</value>
 </property>


Then use the shell 'rsgroup' commands to create and manipulate regionserver groups: e.g. to add a group and then add a server to it, do as follows:

 hbase(main):008:0> add_rsgroup 'my_group'
 Took 0.5610 seconds

This adds a group to the 'hbase:rsgroup' system table. Add a server (hostname + port) to the group using the 'move_rsgroup_servers' command as follows:

 hbase(main):010:0> move_rsgroup_servers 'my_group',['k.att.net:51129']

• Assignee: Francis Christopher Liu
• Reporter: Francis Christopher Liu
• Created: 05/Sep/12 17:41
• Updated: 14/Jun/22 17:50
• Resolved: 15/Mar/16 01:45

Description

In multi-tenant deployments of HBase, it is likely that a RegionServer will be serving out regions from a number of different tables owned by various client applications. Being able to group a subset of running RegionServers and assign specific tables to it, provides a client application a level of isolation and resource allocation.

The proposal essentially is to have an AssignmentManager which is aware of RegionServer groups and assigns tables to region servers based on groupings. Load balancing will occur on a per group basis as well.

This is essentially a simplification of the approach taken in HBASE-4120. See attached document.

Issue Links

• relates to: HBASE-7042 Master Coprocessor Endpoint
• relates to: HBASE-7043 Region Server Group CLI commands
• relates to: HBASE-4120 isolation and allocation
• relates to: HBASE-15631 Backport Regionserver Groups (HBASE-6721) to branch-1

Sub-Tasks

• Implement RegionServer Group Based Balancer: Closed
• RegionServer Groups corpcoessor apis: Closed
• Master Coprocessor Endpoint: Closed
• Region Server Group CLI commands: Closed
• Update Loadbalancer method to throw HBaseIOException: Closed
• Add initialize method to load balancer interface: Closed
• Merge group admin APIs into Admin: Closed
• Backwards compatiblity support for new MasterObserver APIs: Closed
• Forward port some fixes from hbase-6721-0.98 to hbase-6721: Closed
• Add doc for regionserver group-based assignment: Closed
• Fixup of regionserver group-based assignment: Closed
• rsgroup server move can get stuck if unassigning fails: Closed
• Add doc for regionserver groups feature: Closed