以下内容由http://hbase.apache.org/book.html#getting_started节选并改编而来。
运行环境:hadoop-1.0.4,hbase-0.94.22,jdk1.7.0_65
Chapter 1. Getting Started
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,
start and stop HBase
Local Filesystem and Durability
Using HBase 0.98.2 and earlier releases with a local filesystem does not guarantee durability. The HDFS local filesystem implementation will lose edits if files are not properly closed. This is very likely to happen when you are experimenting with new software, starting and stopping the daemons often and not always cleanly. You need to run HBase on HDFS to ensure all writes are preserved. 尽管有bug,我们依然这样做的目的是快速方便地熟悉HBase的相关知识。
Loopback IP - HBase 0.94.x and earlier
Prior to HBase 0.94.x, HBase expected the loopback IP address to be 127.0.0.1. Ubuntu and some other distributions default to 127.0.1.1 and this will cause problems for you . See Why does HBase care about /etc/hosts? for detail.
The following /etc/hosts
file works correctly for HBase 0.94.x and earlier, on Ubuntu. Use this as a template if you run into trouble.
127.0.0.1 localhost 127.0.0.1 ubuntu.ubuntu-domain ubuntu
HBase requires that a JDK be installed. See Table 2.1, “Java” for information about supported JDK versions.
1.2.2. Get Started with HBase
- For HBase 0.98.5 and later, you are required to set the
JAVA_HOME
environment variable before starting HBase. Prior to 0.98.5, HBase attempted to detect the location of Java if the variables was not set. You can set the variable via your operating system‘s usual mechanism, but HBase provides a central mechanism,conf/hbase-env.sh
. Edit this file, uncomment the line starting withJAVA_HOME
, and set it to the appropriate location for your operating system. TheJAVA_HOME
variable should be set to a directory which contains the executable filebin/java
. Most modern Linux operating systems provide a mechanism, such as /usr/bin/alternatives on RHEL or CentOS, for transparently switching between versions of executables such as Java. In this case, you can setJAVA_HOME
to the directory containing the symbolic link tobin/java
, which is usually/usr
.JAVA_HOME=/usr
- Edit main HBase configuration file
conf/hbase-site.xml
. At this time, only need to specify the directory on the local filesystem where HBase and Zookeeper write data. By default, a new directory is created under /tmp. Many servers are configured to delete the contents of /tmp upon reboot, so you should store the data elsewhere. The following configuration will store HBase‘s data in thehbase
directory, in the home directory of the user calledtestuser
. Paste the<property> tags beneath the <configuration> tags, which should be empty in a new HBase install. - Example
hbase-site.xml
for Standalone HBase<configuration> <property> <name>hbase.rootdir</name> <value>file:///home/testuser/hbase</value> //hbase是用户为存储数据而建立的一个目录 </property> <property> //我还没有安装zookeeper,所以没有这部分的配置信息 <name>hbase.zookeeper.property.dataDir</name> <value>/home/testuser/zookeeper</value> </property> </configuration>
- The
bin/start-hbase.sh
script is provided as a convenient way to start 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 calledHMaster
. In standalone mode HBase runs all daemons within this single JVM, i.e. the HMaster, a single HRegionServer, and the ZooKeeper daemon.
Procedure 1.2. Use HBase For the First Time
- Connect to HBase.
$
./bin/hbase shell
hbase(main):001:0> - Display HBase Shell Help Text.
Type
help
and press Enter, to display some basic usage information for HBase Shell, as well as several example commands. - Create a table.
You must specify the table name and the ColumnFamily name.
hbase>
create ‘test‘, ‘cf‘
0 row(s) in 1.2200 seconds - List Information About your Table
hbase>
list ‘test‘
TABLE test 1 row(s) in 0.0350 seconds => ["test"] - Put data into your table.
hbase>
put ‘test‘, ‘row1‘, ‘cf:a‘, ‘value1‘
0 row(s) in 0.1770 seconds hbase>put ‘test‘, ‘row2‘, ‘cf:b‘, ‘value2‘
0 row(s) in 0.0160 seconds hbase>put ‘test‘, ‘row3‘, ‘cf:c‘, ‘value3‘
0 row(s) in 0.0260 seconds - Scan the table for all data at once.
hbase>
scan ‘test‘
ROW COLUMN+CELL row1 column=cf:a, timestamp=1403759475114, value=value1 row2 column=cf:b, timestamp=1403759492807, value=value2 row3 column=cf:c, timestamp=1403759503155, value=value3 3 row(s) in 0.0440 seconds - Get a single row of data.
hbase>
get ‘test‘, ‘row1‘
COLUMN CELL cf:a timestamp=1403759475114, value=value1 1 row(s) in 0.0230 seconds - Disable a table.
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 theenable
command.hbase> disable ‘test‘ 0 row(s) in 1.6270 seconds hbase> enable ‘test‘ 0 row(s) in 0.4500 seconds
hbase> disable ‘test‘ 0 row(s) in 1.6270 seconds
- Drop the table.
hbase> drop ‘test‘ 0 row(s) in 0.2900 seconds
- Exit the HBase Shell.
To exit the HBase Shell and disconnect from your cluster, use the quit command.
- Stop HBase
-
$ ./bin/stop-hbase.sh stopping hbase.................... $
1.2.3. Intermediate - Pseudo-Distributed Local Install
You can re-configure HBase to run in pseudo-distributed mode. Pseudo-distributed mode means that HBase still runs completely on a single host, but each HBase daemon (HMaster, HRegionServer, and Zookeeper) runs as a separate process. By default, unless you configure the hbase.rootdir
property as described in Section 1.2, “Quick Start - Standalone HBase”, your data is still stored in /tmp/
. In this walk-through, we store your data in HDFS instead, assuming you have HDFS available.
我启动hbase后只有HMaster而无HRegionServer,为什么???? 我需要换乘Hadoop2
Hadoop Configuration
This procedure assumes that you have configured Hadoop and HDFS on your local system and or a remote system, and that they are running and available. It also assumes you are using Hadoop 2. Currently, the documentation on the Hadoop website does not include a quick start for Hadoop 2, but the guide athttp://www.alexjf.net/blog/distributed-systems/hadoop-yarn-installation-definitive-guide is a good starting point.
- Stop HBase if it is running.
If you have just finished Section 1.2, “Quick Start - Standalone HBase” 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.xml
configuration. First, add the following property. which directs HBase to run in distributed mode, with one JVM instance per daemon.<property> <name>hbase.cluster.distributed</name> <value>true</value> </property>
Next, change the
hbase.rootdir
from the local filesystem to the address of your HDFS instance, using thehdfs:////
URI syntax. In this example, HDFS is running on the localhost at port 8020.<property> <name>hbase.rootdir</name> <value>hdfs://localhost:8020/hbase</value> </property>
You do not need to create the directory in HDFS. HBase will do this for you. If you create the directory, HBase will attempt to do a migration, which is not what you want.
- Start HBase.
Use the
bin/start-hbase.sh
command to start HBase. If your system is configured correctly, the jps command should show the HMaster and HRegionServer processes running. - Check the HBase directory in HDFS.
If everything worked correctly, HBase created its directory in HDFS. In the configuration above, it is stored in
/hbase/
on HDFS. You can use the hadoop fscommand in Hadoop‘sbin/
directory to list this directory.$
./bin/hadoop fs -ls /hbase
Found 7 items drwxr-xr-x - hbase users 0 2014-06-25 18:58 /hbase/.tmp drwxr-xr-x - hbase users 0 2014-06-25 21:49 /hbase/WALs drwxr-xr-x - hbase users 0 2014-06-25 18:48 /hbase/corrupt drwxr-xr-x - hbase users 0 2014-06-25 18:58 /hbase/data -rw-r--r-- 3 hbase users 42 2014-06-25 18:41 /hbase/hbase.id -rw-r--r-- 3 hbase users 7 2014-06-25 18:41 /hbase/hbase.version drwxr-xr-x - hbase users 0 2014-06-25 21:49 /hbase/oldWALs - Create a table and populate it with data.
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 Procedure 1.2, “Use HBase For the First Time”.
- Start and stop a backup HBase Master (HMaster) server.
Note
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.sh. For each backup master you want to start, add a parameter representing the port offset for that master. Each HMaster uses three ports (16010, 16020, and 16030 by default). The port offset is added to these ports, so using an offset of 2, the backup HMaster would use ports 16012, 16022, and 16032. The following command starts 3 backup servers using ports 16012/16022/16032, 16013/16023/16033, and 16015/16025/16035.
$ ./bin/local-master-backup.sh 2 3 5
To kill a backup master without killing the entire cluster, you need to find its process ID (PID). The PID is stored in a file with a name like
/tmp/hbase-
. The only contents of the file are the PID. You can use the kill -9 command to kill that PID. The following command will kill the master with port offset 1, but leave the cluster running:USER
-X
-master.pid$ cat /tmp/hbase-testuser-1-master.pid |xargs kill -9
- Start and stop additional RegionServers
The HRegionServer manages the data in its StoreFiles as directed by the HMaster. 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.sh command allows you to run multiple RegionServers. It works in a similar way to the local-master-backup.sh command, in that each parameter you provide represents the port offset for an instance. Each RegionServer requires two ports, and the default ports are 16020 and 16030. However, the base ports for additional RegionServers are not the default ports since the default ports are used by the HMaster, which is also a RegionServer since HBase version 1.0.0. The base ports are 16200 and 16300 instead. You can run 99 additional RegionServers that are not a HMaster or backup HMaster, on a server. The following command starts four additional RegionServers, running on sequential ports starting at 16202/16302 (base ports 16200/16300 plus 2).
$ .bin/local-regionservers.sh start 2 3 4 5
To stop a RegionServer manually, use the local-regionservers.sh command with the
stop
parameter and the offset of the server to stop.$ .bin/local-regionservers.sh stop 3
- Stop HBase.
You can stop HBase the same way as in the Section 1.2, “Quick Start - Standalone HBase” procedure, using the
bin/stop-hbase.sh
command.
1.2.4. 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. These include primary and backup Master instances, multiple Zookeeper nodes, and multiple RegionServer nodes.
This advanced quickstart adds two more nodes to your cluster. The architecture will be as follows:
Table 1.1. Distributed Cluster Demo Architecture
Node Name | Master | ZooKeeper | RegionServer |
---|---|---|---|
node-a.example.com | yes | yes | no |
node-b.example.com | backup | yes | yes |
node-c.example.com | no | yes | yes |
This quickstart assumes that each node is a virtual machine and that they are all on the same network. It builds upon the previous quickstart, Section 1.2.3, “Intermediate - Pseudo-Distributed Local Install”, assuming that the system you configured in that procedure is now node-a
. Stop HBase on node-a
before continuing.
Note
Be sure that all the nodes have full access to communicate, and that no firewall rules are in place which could prevent them from talking to each other. If you see any errors like no route to host
, check your firewall.
Procedure 1.4. Configure Password-Less SSH Access
node-a
needs to be able to log into node-b
and node-c
(and to itself) in order to start the daemons. The easiest way to accomplish this is to use the same username on all hosts, and configure password-less SSH login from node-a
to each of the others.
- On
node-a
, generate a key pair.While logged in as the user who will run HBase, generate a SSH key pair, using the following command:
$ ssh-keygen -t rsa
If the command succeeds, the location of the key pair is printed to standard output. The default name of the public key is
id_rsa.pub
. - Create the directory that will hold the shared keys on the other nodes.
On
node-b
andnode-c
, log in as the HBase user and create a.ssh/
directory in the user‘s home directory, if it does not already exist. If it already exists, be aware that it may already contain other keys. - Copy the public key to the other nodes.
Securely copy the public key from
node-a
to each of the nodes, by using the scp or some other secure means. On each of the other nodes, create a new file called.ssh/authorized_keys
if it does not already exist, and append the contents of theid_rsa.pub
file to the end of it. Note that you also need to do this fornode-a
itself.$ cat id_rsa.pub >> ~/.ssh/authorized_keys
- Test password-less login.
If you performed the procedure correctly, if you SSH from
node-a
to either of the other nodes, using the same username, you should not be prompted for a password. - Since
node-b
will run a backup Master, repeat the procedure above, substitutingnode-b
everywhere you seenode-a
. Be sure not to overwrite your existing.ssh/authorized_keys
files, but concatenate the new key onto the existing file using the>>
operator rather than the>
operator.
Procedure 1.5. Prepare node-a
node-a
will run your primary master and ZooKeeper processes, but no RegionServers.
- Stop the RegionServer from starting on
node-a
.Edit
conf/regionservers
and remove the line which containslocalhost
. Add lines with the hostnames or IP addresses fornode-b
andnode-c
. Even if you did want to run a RegionServer onnode-a
, you should refer to it by the hostname the other servers would use to communicate with it. In this case, that would benode-a.example.com
. This enables you to distribute the configuration to each node of your cluster any hostname conflicts. Save the file. - Configure HBase to use
node-b
as a backup master.Create a new file in
conf/
calledbackup-masters
, and add a new line to it with the hostname fornode-b
. In this demonstration, the hostname isnode-b.example.com
. - Configure ZooKeeper
In reality, you should carefully consider your ZooKeeper configuration. You can find out more about configuring ZooKeeper in Chapter 20, ZooKeeper. This configuration will direct HBase to start and manage a ZooKeeper instance on each node of the cluster.
On
node-a
, editconf/hbase-site.xml
and add the following properties.<property> <name>hbase.zookeeper.quorum</name> <value>node-a.example.com,node-b.example.com,node-c.example.com</value> </property> <property> <name>hbase.zookeeper.property.dataDir</name> <value>/usr/local/zookeeper</value> </property>
- Everywhere in your configuration that you have referred to
node-a
aslocalhost
, change the reference to point to the hostname that the other nodes will use to refer tonode-a
. In these examples, the hostname isnode-a.example.com
.
Procedure 1.6. Prepare node-b
and node-c
node-b
will run a backup master server and a ZooKeeper instance.
- Download and unpack HBase.
Download and unpack HBase to
node-b
, just as you did for the standalone and pseudo-distributed quickstarts. - Copy the configuration files from
node-a
tonode-b
.andnode-c
.Each node of your cluster needs to have the same configuration information. Copy the contents of the
conf/
directory to theconf/
directory onnode-b
andnode-c
.
Procedure 1.7. Start and Test Your Cluster
- Be sure HBase is not running on any node.
If you forgot to stop HBase from previous testing, you will have errors. Check to see whether HBase is running on any of your nodes by using the jps command. Look for the processes
HMaster
,HRegionServer
, andHQuorumPeer
. If they exist, kill them. - Start the cluster.
On
node-a
, issue the start-hbase.sh command. Your output will be similar to that below.$
bin/start-hbase.sh
node-c.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-c.example.com.out node-a.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-a.example.com.out node-b.example.com: starting zookeeper, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-zookeeper-node-b.example.com.out starting master, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-master-node-a.example.com.out node-c.example.com: starting regionserver, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-regionserver-node-c.example.com.out node-b.example.com: starting regionserver, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-regionserver-node-b.example.com.out node-b.example.com: starting master, logging to /home/hbuser/hbase-0.98.3-hadoop2/bin/../logs/hbase-hbuser-master-nodeb.example.com.outZooKeeper starts first, followed by the master, then the RegionServers, and finally the backup masters.
- Verify that the processes are running.
On each node of the cluster, run the jps command and verify that the correct processes are running on each server. You may see additional Java processes running on your servers as well, if they are used for other purposes.
Example 1.3.
node-a
jps Output$
jps
20355 Jps 20071 HQuorumPeer 20137 HMasterExample 1.4.
node-b
jps Output$
jps
15930 HRegionServer 16194 Jps 15838 HQuorumPeer 16010 HMasterExample 1.5.
node-c
jps Output$
jps
13901 Jps 13639 HQuorumPeer 13737 HRegionServerZooKeeper Process Name
The
HQuorumPeer
process is a ZooKeeper instance which is controlled and started by HBase. If you use ZooKeeper this way, it is limited to one instance per cluster node, , and is appropriate for testing only. If ZooKeeper is run outside of HBase, the process is calledQuorumPeer
. For more about ZooKeeper configuration, including using an external ZooKeeper instance with HBase, see Chapter 20, ZooKeeper. - Browse to the Web UI.
Web UI Port Changes
In HBase newer than 0.98.x, the HTTP ports used by the HBase Web UI changed from 60010 for the Master and 60030 for each RegionServer to 16610 for the Master and 16030 for the RegionServer.
If everything is set up correctly, you should be able to connect to the UI for the Master
http://node-a.example.com:60110/
or the secondary master athttp://node-b.example.com:60110/
for the secondary master, using a web browser. If you can connect vialocalhost
but not from another host, check your firewall rules. You can see the web UI for each of the RegionServers at port 60130 of their IP addresses, or by clicking their links in the web UI for the Master. - Test what happens when nodes or services disappear.
With a three-node cluster like you have configured, things will not be very resilient. Still, you can test what happens when the primary Master or a RegionServer disappears, by killing the processes and watching the logs.
1.2.5. Where to go next
The next chapter, Chapter 2, Apache HBase Configuration, gives more information about the different HBase run modes, system requirements for running HBase, and critical configuration areas for setting up a distributed HBase cluster.