ndimiduk commented on a change in pull request #1164: HBASE-23331:
Documentation for HBASE-18095
URL: https://github.com/apache/hbase/pull/1164#discussion_r378612539
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File path: src/main/asciidoc/_chapters/configuration.adoc
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@@ -563,38 +563,63 @@ Changes here will require a cluster restart for HBase to
notice the change thoug
If you are running HBase in standalone mode, you don't need to configure
anything for your client to work provided that they are all on the same machine.
-Since the HBase Master may move around, clients bootstrap by looking to
ZooKeeper for current critical locations.
-ZooKeeper is where all these values are kept.
-Thus clients require the location of the ZooKeeper ensemble before they can do
anything else.
-Usually this ensemble location is kept out in the _hbase-site.xml_ and is
picked up by the client from the `CLASSPATH`.
+Starting release 3.0.0, the default connection registry has been switched to a
master based implementation. Refer to <<client.masterregistry>> for more
details about
+what a connection registry is and implications of this change. Depending on
your HBase version, following is the expected minimal client configuration.
-If you are configuring an IDE to run an HBase client, you should include the
_conf/_ directory on your classpath so _hbase-site.xml_ settings can be found
(or add _src/test/resources_ to pick up the hbase-site.xml used by tests).
+==== Up until 2.x.y releases
+In 2.x.y releases, the default connection registry was based on ZooKeeper as
the source of truth. This means that the clients always looked up ZooKeeper
znodes to fetch
+the required metadata. For example, if an active master crashed and the a new
master is elected, clients looked up the master znode to fetch
+the active master address (similarly for meta locations). This meant that the
clients needed to have access to ZooKeeper and need to now
+the ZooKeeper ensemble information before they can do anything. This can be
configured in the client configuration xml as follows:
-For Java applications using Maven, including the hbase-shaded-client module is
the recommended dependency when connecting to a cluster:
[source,xml]
----
-<dependency>
- <groupId>org.apache.hbase</groupId>
- <artifactId>hbase-shaded-client</artifactId>
- <version>2.0.0</version>
-</dependency>
+<?xml version="1.0"?>
+<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
+<configuration>
+ <property>
+ <name>hbase.zookeeper.quorum</name>
+ <value>example1,example2,example3</value>
+ <description> Zookeeper ensemble information</description>
+ </property>
+</configuration>
----
-A basic example _hbase-site.xml_ for client only may look as follows:
+==== Starting 3.0.0 release
+
+The default implementation was switched to a master based connection registry.
With this implementation, clients always contact the active or
+stand-by master RPC end points to fetch the the connection registry
information. This means that the clients should have access to the list of
active and master
+end points before they can do anything. This can be configured in the client
configuration xml as follows:
+
[source,xml]
----
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<configuration>
<property>
- <name>hbase.zookeeper.quorum</name>
+ <name>hbase.masters</name>
<value>example1,example2,example3</value>
- <description>The directory shared by region servers.
- </description>
+ <description>List of master rpc end points for the hbase
cluster.</description>
</property>
</configuration>
----
+The configuration value for _hbase.masters_ is a comma separated list of
_host:port_ values. If no port value is specified, the default of _16000_ is
assumed.
+
+Usually this configuration is kept out in the _hbase-site.xml_ and is picked
up by the client from the `CLASSPATH`.
+
+If you are configuring an IDE to run an HBase client, you should include the
_conf/_ directory on your classpath so _hbase-site.xml_ settings can be found
(or add _src/test/resources_ to pick up the hbase-site.xml used by tests).
+
+For Java applications using Maven, including the hbase-shaded-client module is
the recommended dependency when connecting to a cluster:
+[source,xml]
Review comment:
nit: is dependency information relevant in the configuration section?
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