Mailing-List: contact user-help@zookeeper.apache.org; run by ezmlm
Precedence: bulk
Reply-To: user@zookeeper.apache.org
Received-SPF: pass (nike.apache.org: domain of rakeshr@huawei.com designates
 119.145.14.65 as permitted sender)
From: Rakesh R <rakeshr@huawei.com>
To: "user@zookeeper.apache.org" <user@zookeeper.apache.org>,
        "zookeeper-user@hadoop.apache.org" <zookeeper-user@hadoop.apache.org>
CC: "rajeshkumarit8292@gmail.com" <rajeshkumarit8292@gmail.com>
Subject: RE: zookeeper in hadoop
Thread-Topic: zookeeper in hadoop
Thread-Index: AQHPuqkN2Rzx0aWh60mw/56kMG56Z5vV4JIA
Date: Mon, 18 Aug 2014 08:24:21 +0000
Message-ID: 
 <C2496325850AA74C92AAF83AA9662D26458CCE92@szxeml561-mbx.china.huawei.com>
References: <1408341306344-7580179.post@n2.nabble.com>
In-Reply-To: <1408341306344-7580179.post@n2.nabble.com>
Accept-Language: en-US, zh-CN
Content-Language: en-US
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: quoted-printable
MIME-Version: 1.0

Hi,

AFAIK following are few cases where ZK is used in Hadoop & BookKeeper compo=
nents.

Hadoop is using ZK to provides the high-availability of the Master process =
like,

1) HDFS is using ZK for making the NameNode highly available.=20
Also, BKJM(uses BookKeeper as journal manager) which is a sub-module in the=
 HDFS to store WAL(editlog transactions)
http://hadoop.apache.org/docs/r2.3.0/hadoop-yarn/hadoop-yarn-site/HDFSHighA=
vailabilityWithNFS.html

2) YARN is using ZK for making the ResourceManager highly available.=20
Also, they are using it for storing the state of the RM in ZooKeeper(ZKRMSt=
ateStore: A ZooKeeper-based state-store implementation)
http://hadoop.apache.org/docs/r2.4.0/hadoop-yarn/hadoop-yarn-site/ResourceM=
anagerRestart.html#Configurations


BookKeeper is using ZK for :

1) service discovery - to know the details about the running BK servers
2) metadata storage - keeps all the meta data about the ledgers(user data)
3) Auto-recovery - handle missing replicas to improve the fault-tolerance.
http://zookeeper.apache.org/bookkeeper/


Regards,
Rakesh
-----Original Message-----
From: mufc_fan [mailto:rajeshkumarit8292@gmail.com]=20
Sent: 18 August 2014 11:25
To: zookeeper-user@hadoop.apache.org
Subject: zookeeper in hadoop

I am new to zookeeper and from the documentation I learnt that "zookeeper i=
s a sub-project of hadoop". so zookeeper must be used in hadoop. Can any on=
e share their knowledge how zookeeper is used in hadoop with simple example=
.


--
View this message in context: http://zookeeper-user.578899.n2.nabble.com/zo=
okeeper-in-hadoop-tp7580179.html
Sent from the zookeeper-user mailing list archive at Nabble.com.