hbase in action - chapter 09: deploying hbase

Chapter 09: Deploying HBase

HBase IN ACTIONby Nick Dimiduk et. al.

Overview: Deploying HBase

Planning your clusterDeploying softwareDistributionsConfigurationManaging the daemonsSummary

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9.1 Planning your cluster

Planning an HBase cluster includes planning the underlying Hadoop cluster.

This section will highlight the considerations to keep in mind when choosing hardware and how the roles (HBase Master, RegionServers, ZooKeeper, and so on) should be deployed on the cluster. Prototype cluster

A prototype cluster is one that doesn’t have strict SLAs, and it’s okay for it to go

down. Collocate the HBase Master with the Hadoop NameNode and JobTracker

on the same node. It typically has fewer than 10 nodes. It’s okay to collocate multiple services on a single node in a prototype

cluster. 4–6 cores, 24–32 GB RAM, and 4 disks per node should be a good place

to start.

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9.1 Planning your cluster (con't)

Small production cluster (10–20 servers) : Generally, you shouldn’t have fewer than 10 nodes in a production HBase cluster. Fewer than 10 slave nodes is hard to make operationalize. Consider relatively better hardware for the Master nodes if

you’re deploying a production cluster. Dual power supplies and perhaps RAID are the order of the day.

Small production clusters with not much traffic/workload can have services collocated.

A single HBase Master is okay for small clusters. A single ZooKeeper is okay for small clusters and can be

collocated with the HBase Master. If the host running the NameNode and JobTracker is beefy enough, put ZooKeeper and HBase Master on it too. This will save you having to buy an extra machine.

A single HBase Master and ZooKeeper limits serviceability.

Hbase Course

Data Manipulation at Scale: Systems and Algorithms

Using HBase for Real-time Access to Your Big Data

05/01/23

9.1 Planning your cluster (con't)

Medium production cluster (up to ~50 servers) Up to 50 nodes, possibly in production, would fall in this category. We recommend that you not collocate HBase and MapReduce

for performance reasons. If you do collocate, deploy NameNode and JobTracker on separate hardware.

Three ZooKeeper and three HBase Master nodes should be deployed, especially if this is a production system. You don’t need three HBase Masters and can do with two; but given that you already have three ZooKeeper nodes and are sharing ZooKeeper and HBase Master, it doesn’t hurt to have a third Master.

Don’t cheap out on the hardware for the NameNode and Secondary NameNodes.

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9.1 Planning your cluster (con't)

Large production cluster (>~50 servers) Everything for the medium-sized cluster holds true, except that

you may need five ZooKeeper instances that can also collocate with HBase Masters.

Make sure NameNode and Secondary NameNode have enough memory, depending on the storage capacity of the cluster.

Hadoop Master nodes Have redundancy at the hardware level for the various

components: NICs, RAID disks There is enough RAM to be able to address the entire

namespace : Namenode The Secondary NameNode should have the same hardware as

the NameNode.

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9.1 Planning your cluster (con't)

HBase Master HBase Master is a lightweight process and doesn’t need a lot of

resources, but it’s wise to keep it on independent hardware if possible.

Have multiple HBase Masters for redundancy. cores, 8–16 GB RAM, and 2 disks are more than enough for the

HBase Master nodes.Hadoop DataNodes and HBase RegionServers

DataNodes and RegionServers are always collocated. They serve the traffic. Avoid running MapReduce on the same nodes.

8–12 cores, 24–32 GB RAM, 12x 1 TB disks is a good place to start. You can increase the number of disks for higher storage density, but

don’t go too high or replication will take time in the face of node or disk failure.

Get a larger number of reasonably sized boxes instead of fewer beefy ones.

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9.1 Planning your cluster (con't)

ZooKeeper(s) ZooKeepers are lightweight but latency sensitive. Hardware similar to that of the HBase Master works fine if you’re

looking to deploy them separately. HBase Master and ZooKeeper can be collocated safely as long as

you make sure ZooKeeper gets a dedicated spindle for its data persistence.

Add a disk (for the ZooKeeper data to be persisted on) to the configuration mentioned in the HBase Master section if you’re collocating.

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9.1 Planning your cluster (con't)

What about the cloud? At least 16 GB RAM. HBase RegionServers are RAM hungry. But

don’t give them too much, or you’ll run into Java GC issues. We’ll talk about tuning GC later in this chapter.

Have as many disks as possible. Most EC2 instances at the time of writing don’t provide a high number of disks.

A fatter network is always better. Get ample compute based on your individual use case. MapReduce

jobs need more compute power than a simple website-serving database.

It’s important that you’re aware of the arguments in favor of and against deploying HBase in the cloud. Cost Ease of use Operations Reliability Lack of customization Performance Security

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9.2 Deploying software

Managing and deploying on a cluster of machines, especially in production, is nontrivial and needs careful work.

When deploying to a large number of machines, we recommend that you automate the process as much as possible.

Our intent is to introduce you to all the ways you can think about deployments. Whirr: deploying in the cloud : If you’re looking to deploy HBase in

the cloud, you should get Apache Whirr to make your life easier.

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9.3 Distributions

This section will cover installing HBase on your cluster. Numerous distributions (or packages) of HBase are available, and each has multiple releases. The most notable distributions currently are the stock Apache distribution and Cloudera’s CDH: Apache : The Apache HBase project is the parent project where all

the development for HBase happens. Cloudera’s CDH : Cloudera is a company that has its own

distribution containing Hadoop and other components in the ecosystem, including HBase.

We recommend using Cloudera’s CDH distribution. It typically includes more patches than the stock releases to add stability, performance improvements, and sometimes features.

CDH is also better tested than the Apache releases and is running in production in more clusters than stock Apache. These are points we recommend thinking about before you choose the distribution for your cluster.

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9.3.1 Using the stock Apache distribution

To install the stock Apache distribution, you need to download the tarballs and install those into a directory of your choice.

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9.3.2 Using Cloudera’s CDH distribution

The current release for CDH is CDH4u0 which is based on the 0.92.1 Apache release. The installation instructions are environment specific; the fundamental steps are as follows:

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9.4 Configuration

Deploying HBase requires configuring Linux, Hadoop, and, of course, HBase.

In order to configure the system in the most optimal manner, it’s important that you understand the parameters and the implications of tuning them one way or another.

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9.4.1 HBase configurations

ENVIRONMENT CONFIGURATIONS : hbase-env.sh things like the Java heap size, garbage-collection parameters, and other environment variables are set here.

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9.4.1 HBase configurations (con't)

The configuration parameters for HBase daemons are put in an XML file called hbase-site.xml.

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9.4.1 HBase configurations (con't)

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9.4.2 Hadoop configuration parameters relevant to HBase

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9.4.3 Operating system configurations

HBase is a database and needs to keep files open so you can read from and write to them without incurring the overhead of opening and closing them on each operation.

To increase the open-file limit for the user, put the following statements in your /etc/ security/limits.conf file for the user that will run the Hadoop and HBase daemons. CDH does this for you as a part of the package installation:

hadoopuser nofile 32768hbaseuser nofile 32768hadoopuser soft/hard nproc 32000hbaseuser soft/hard nproc 32000

Another important configuration parameter to tune is the swap behavior.$ sysctl -w vm.swappiness=0

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9.5 Managing the daemons

The relevant services need to be started on each node of the cluster : Use the bundled start and stop scripts. Cluster SSH (http://sourceforge.net/projects/clusterssh) is a useful

tool if you’re dealing with a cluster of machines. It allows you to simultaneously run the same shell commands on a cluster of machines that you’re logged in to in separate windows.

Homegrown scripts are always an option. Use management software like Cloudera Manager that allows you

to manage all the services on the cluster from a single web-based UI.

Hbase Course

Data Manipulation at Scale: Systems and Algorithms

Using HBase for Real-time Access to Your Big Data

05/01/23

9.5 Summary

In this chapter, we covered the various aspects of deploying HBase in a fully distributed environment for your production application. We talked about the considerations to take into account when

choosing hardware for your cluster, including whether to deploy on your own hardware or in the cloud.

This chapter gets you ready to think about putting HBase in production.