Hadoop2.5 HA部署

部署过程参考：http://my.oschina.net/u/1169079/blog/227471?   ;    http://blog.debugo.com/namenode-ha/

        hadoop中的NameNode好比是人的心脏，非常重要，绝对不可以停止工作。在hadoop1时代，只有一个NameNode。如果该NameNode数据丢失或者不能工作，那么整个集群就不能恢复了。这是hadoop1中的单点问题，也是hadoop1不可靠的表现，如图1所示。hadoop2就解决了这个问题。

hadoop2.2.0中HDFS的高可靠指的是可以同时启动2个NameNode。其中一个处于工作状态，另一个处于随时待命状态。这样，当一个NameNode所在的服务器宕机时，可以在数据不丢失的情况下，手工或者自动切换到另一个NameNode提供服务。

        这些NameNode之间通过共享数据，保证数据的状态一致。多个NameNode之间共享数据，可以通过Nnetwork File System或者Quorum Journal Node。前者是通过linux共享的文件系统，属于操作系统的配置；后者是hadoop自身的东西，属于软件的配置。

        我们这里讲述使用Quorum Journal Node的配置方式，方式是手工切换。

        集群启动时，可以同时启动2个NameNode。这些NameNode只有一个是active的，另一个属于standby状态。active状态意味着提供服务，standby状态意味着处于休眠状态，只进行数据同步，时刻准备着提供服务。

环境：

操作系统：CentOS 6.2 x64
hadoop版本：hadoop-2.5.2.tar.gz
zookeeper 版本：zookeeper-3.4.6.tar.gz

添加hosts记录：
10.0.2.54 hnn01
10.0.2.55 hnn02
10.0.2.62 yarnzk
10.0.2.63 hdn01zk
10.0.2.64 hdn02zk

                            角色分布：

IP地址	主机名	角色
10.0.2.54	hnn01	Namenode01 + journal
10.0.2.55	hnn02	Namenode02 + journal
10.0.2.62	yarnzk	Yarn + zookpeer + journal
10.0.2.63	hdn01zk	Datanode + zookeeper
10.0.2.64	hdn02zk	Datanode + zookeeper

1.互信：

[root@hnn01 ~]# ssh-keygen -t rsa
[root@hnn01 ~]# cd .ssh/ ; cp id_rsa.pub authorized_keys

Slave机器创建ssh目录 ： mkdir -m 700 /root/.ssh
将公钥复制到Slave机器上：scp authorized_keys hnn02:/root/.ssh/

注：由于完全模拟生产环境，故把角色尽量分开，所以需要做3次互信（hnn01,hnn02,yarnzk）机器都需要

测试无密码登录是否正常 ！！

2.安装zookeeper

[root@yarnzk src]# tar zxf zookeeper-3.4.6.tar.gz
[root@yarnzk src]# mv zookeeper-3.4.6 ../zookeeper
[root@yarnzk local]# cd /usr/local/zookeeper/conf/

vi zoo.cfg
dataDir=/usr/local/zookeeper/zk_data/
server.0=yarnzk:2888:3888
server.1=hdn01zk:2888:3888
server.2=hdn02zk:2888:3888

创建文件夹mkdir /usr/local/zookpeer/zk_data

[root@yarnzk conf]# echo '0' > /usr/local/zookeeper/zk_data/myid
把zk目录复制到hdn01zk和hdn02zk中，并修改myid文件值

启动，在三个节点上分别执行命令zkServer.sh start
检验，在三个节点上分别执行命令zkServer.sh status

3.安装hadoop集群

[root@hnn01 src]# tar zxf hadoop-2.5.2.tar.gz
[root@hnn01 src]# mv hadoop-2.5.2 ../hadoop
[root@hnn01 src]# cd ../hadoop/etc/hadoop/
[root@hnn01 src]# mkdir /usr/local/hadoop/journal

[root@hnn01 hadoop]# vim hadoop-env.sh
export JAVA_HOME=/usr/local/jdk1.7.0_51
export HADOOP_OPTS="$HADOOP_OPTS -Djava.library.path=/usr/local/hadoop/lib/"
export HADOOP_COMMON_LIB_NATIVE_DIR="/usr/local/hadoop/lib/native/"
export HADOOP_CONF_DIR=${HADOOP_CONF_DIR:-"/usr/local/hadoop/etc/hadoop"}

[root@hnn01 hadoop]# vim mapred-env.sh
export JAVA_HOME=/usr/local/jdk1.7.0_51

[root@hnn01 hadoop]# vim yarn-env.sh
export JAVA_HOME=/usr/local/jdk1.7.0_51

[root@hnn01 hadoop]# more core-site.xml

fs.defaultFS

hadoop.tmp.dir
/usr/local/hadoop/hadoop-tmp-${user.name}

hadoop.native.lib
true
Should native hadoop libraries, if present, be used.

hadoop.logfile.size
10000000
日志文件最大为10M

hadoop.logfile.count
10
日志文件数量为10个

io.file.buffer.size
6421772
流文件的缓冲区为128M/60MB

ha.zookeeper.quorum
yarnzk,hdn01zk,hdn02zk

[root@hnn01 hadoop]# more hdfs-site.xml

dfs.nameservices
myhdfs

dfs.replication
2

dfs.ha.namenodes.myhdfs
nn1,nn2

dfs.namenode.rpc-address.myhdfs.nn1
hnn01:54310

dfs.namenode.rpc-address.myhdfs.nn2
hnn02:54310

dfs.namenode.http-address.myhdfs.nn1
hnn01:50070

dfs.namenode.http-address.myhdfs.nn2
hnn02:50070

dfs.namenode.shared.edits.dir
qjournal://hnn01:8485;hnn02:8485;yarnzk:8485hadoop-journal

dfs.ha.automatic-failover.enabled
true

dfs.journalnode.edits.dir
/usr/local/hadoop/journal

dfs.client.failover.proxy.provider.myhdfs
org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider

dfs.ha.fencing.methods
sshfence
how to communicate in the switch process

dfs.ha.fencing.ssh.private-key-files
/root/.ssh/id_rsa
the location stored ssh key

dfs.ha.fencing.ssh.connect-timeout
5000

dfs.namenode.name.dir
${hadoop.tmp.dir}/dfs/name,/data/dfs/name

dfs.datanode.data.dir
/data0/dfs/data,/data1/dfs/data,/data2/dfs/data

dfs.namenode.handler.count
200

dfs.datanode.handler.count
12

dfs.webhdfs.enabled
true

dfs.balance.bandwidthPerSec
26214400
balancer传输速度25M/s,默认1M（52428800 = 50M/s）

dfs.safemode.threshold.pct
0.9

dfs.datanode.max.xcievers
5120

dfs.client.block.write.retries
3

fs.trash.interval
600

dfs.client.failover.proxy.provider.myhdfs
org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider
Configure the name of the Java class which will be used by the DFS Client to determine which NameNode is the current Active, and

therefore which NameNode is currently serving client requests. 这个类是Client的访问代理，是HA特性对于Client透明的关键！

[root@hnn01 hadoop]# more mapred-site.xml

mapreduce.framework.name
yarn

mapred.system.dir
${hadoop.tmp.dir}/system

mapred.local.dir
${hadoop.tmp.dir}/mapred-local

mapreduce.jobhistory.address
yarnzk:54311

mapreduce.jobhistory.webapp.address
yarnzk:19888

[root@hnn01 hadoop]# more yarn-site.xml

yarn.nodemanager.aux-services
mapreduce_shuffle

yarn.nodemanager.aux-services.mapreduce.shuffle.class

org.apache.hadoop.mapred.ShuffleHandler

yarn.resourcemanager.address
yarnzk:8032

yarn.resourcemanager.scheduler.address
yarnzk:8030

yarn.resourcemanager.resource-tracker.address
yarnzk:8031

yarn.resourcemanager.admin.address
yarnzk:8033

yarn.resourcemanager.webapp.address
yarnzk:50030

[root@hnn01 hadoop]# more slaves
hdn01zk
hdn02zk

将修改好的hadoop目录拷贝到各个节点：
[root@hnn01 local]# scp -r hadoop yarnzk:/usr/local/

为datanode节点创建数据目录：
[root@hnn01 sbin]# ./slaves.sh mkdir /data{0,1,2}/dfs/

拷贝系统/环境变量到各个服务器：
[root@hnn01 ~]# scp /etc/hosts /etc/profile hnn02:/etc/

[root@hnn01 ~]# hdfs zkfc -formatZK

在每个JournalNode上执行(否则启动服务时会报错)：
/usr/local/hadoop/sbin/hadoop-daemon.sh start journalnode

第一次启动格式化HDFS
hdfs namenode -format

在每个JournalNode上执行(否则启动服务时会报错)：
/usr/local/hadoop/sbin/hadoop-daemon.sh stop journalnode

启动hdfs服务：
[root@hnn01 sbin]# ./start-dfs.sh
Starting namenodes on [hnn01 hnn02]
hnn01: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-hnn01.out
hnn02: starting namenode, logging to /usr/local/hadoop/logs/hadoop-root-namenode-hnn02.out
hdn01zk: starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-hdn01zk.out
hdn02zk: starting datanode, logging to /usr/local/hadoop/logs/hadoop-root-datanode-hdn02zk.out
Starting journal nodes [hnn01 hnn02 yarnzk]
hnn02: starting journalnode, logging to /usr/local/hadoop/logs/hadoop-root-journalnode-hnn02.out
yarnzk: starting journalnode, logging to /usr/local/hadoop/logs/hadoop-root-journalnode-yarnzk.out
hnn01: starting journalnode, logging to /usr/local/hadoop/logs/hadoop-root-journalnode-hnn01.out
Starting ZK Failover Controllers on NN hosts [hnn01 hnn02]
hnn02: starting zkfc, logging to /usr/local/hadoop/logs/hadoop-root-zkfc-hnn02.out
hnn01: starting zkfc, logging to /usr/local/hadoop/logs/hadoop-root-zkfc-hnn01.out

[root@hnn01 sbin]# jps
20422 Jps
17813 JournalNode
18174 DFSZKFailoverController
17595 NameNode

访问 会看到该节点已经成为active

下面需要同步一次元数据：
hnn02 上执行：

hdfs namenode -bootstrapStandby
15/03/09 15:38:37 INFO namenode.NameNode: registered UNIX signal handlers for [TERM, HUP, INT]
15/03/09 15:38:37 INFO namenode.NameNode: createNameNode [-bootstrapStandby]
15/03/09 15:38:37 WARN common.Util: Path /usr/local/hadoop/hadoop-tmp-root/dfs/name should be specified as a URI in configuration files. Please update hdfs configuration.
15/03/09 15:38:37 WARN common.Util: Path /data/dfs/name should be specified as a URI in configuration files. Please update hdfs configuration.
15/03/09 15:38:37 WARN common.Util: Path /usr/local/hadoop/hadoop-tmp-root/dfs/name should be specified as a URI in configuration files. Please update hdfs configuration.
15/03/09 15:38:37 WARN common.Util: Path /data/dfs/name should be specified as a URI in configuration files. Please update hdfs configuration.
=====================================================
About to bootstrap Standby ID nn1 from:
Nameservice ID: myhdfs
Other Namenode ID: nn2
Other NN's HTTP address:
Other NN's IPC address: hnn02/10.0.2.55:54310
Namespace ID: 108854670
Block pool ID: BP-1908663152-10.0.2.54-1425550312574
Cluster ID: CID-687b459e-7b9e-4162-9c25-3061545b1ebb
Layout version: -57
=====================================================
Re-format filesystem in Storage Directory /usr/local/hadoop/hadoop-tmp-root/dfs/name ? (Y or N) Y
Re-format filesystem in Storage Directory /data/dfs/name ? (Y or N) Y
15/03/09 15:39:28 INFO common.Storage: Storage directory /usr/local/hadoop/hadoop-tmp-root/dfs/name has been successfully formatted.
15/03/09 15:39:28 INFO common.Storage: Storage directory /data/dfs/name has been successfully formatted.

访问 会看到该节点已经成为standby

然后kill掉hnn01上的active NN进程，standby NN会成为active
注意：手动切换时，会提示下面警告。所以一般在启动zkfc的情况下也无需进行切换。

hdfs haadmin -transitionToActive nn1

启动yarn服务：
[root@yarnzk sbin]# ./start-yarn.sh
starting yarn daemons
starting resourcemanager, logging to /usr/local/hadoop/logs/yarn-root-resourcemanager-yarnzk.out
hdn02zk: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-root-nodemanager-hdn02zk.out
hdn01zk: starting nodemanager, logging to /usr/local/hadoop/logs/yarn-root-nodemanager-hdn01zk.out
[root@yarnzk sbin]# jps
6994 QuorumPeerMain
13657 ResourceManager
13537 JournalNode
14174 Jps

访问