6-zookeeper-hadoop-ha故障转移机制，原理简述:

HA概述（2.X版本架构）。

1）、HA（High available），即高可用（7*24小时不间断服务。）

1、zookeeper协调服务，通知

2、zkfc是一个zookeeper的一个客户端，用于帮助namenode和zookeeper进行联系，管理namenode的状态。

3、3步骤通过zookeeper通知领一个客户端。

HDFS-HA集群配置

规划

hadoop102	hadoop103	hadoop104
NameNode	NameNode
JournalNode	JournalNode	JournalNode
DataNode	DataNode	DataNode
ZK	ZK	ZK
zkfc	zkfc	zkfc
	ResourceManager
NodeManager	NodeManager	NodeManager

1.拷贝原有hadoop。

[root@hadoop102 module]# mkdir ha

[root@hadoop102 module]# cp -r hadoop-3.1.4/ ha/

[root@hadoop102 hadoop]# pwd
/opt/module/ha/hadoop-3.1.4/etc/hadoop

2、配置core-site.xml

core-site.xml



fs.defaultFS
hdfs://mycluster



hadoop.tmp.dir
/opt/module/ha/hadoop-3.1.4/data

3、配置hdfs.xml

core-site.xml



dfs.nameservices
mycluster



dfs.ha.namenode.mycluster
nn1,nn2



dfs.namenode.rpc-address.mycluster.nn1
hadoop102:9000



dfs.namenode.rpc-address.mycluster.nn2
hadoop102:9000



dfs.namenode.http-address.mycluster.nn1
hadoop102:50070



dfs.namenode.http-address.mycluster.nn2
hadoop102:50070

	 dfs.namenode.shared.edits.dirqjournal://hadoop102:8485;hadoop103:8485;hadoop104:8485/mycluster

​
​
​
​ dfs.ha.fencing.methods
​ sshfence
​
​


dfs.ha.fencing.ss.private-key-files
/root/.ssh/id_rsa

​
​
​
​ dfs.journalnode.edits.dir
​ /opt/module/ha/hadoop-3.1.4/data/jn
​
​
​
​ dfs.permissions.enable
​ false
​
​
​
​ dfs.client.failover.proxy.provider.mycluster
​ org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider
​
​
​
​ dfs.ha.automatic-failover.enabled
​ true
​

4、分发ha

[root@hadoop102 module]# xsync ha

5、启动qjm集群，数据存储的地方。

[root@hadoop102 hadoop-3.1.4]# sbin/hadoop-daemons.sh start journalnode
WARNING: Use of this script to start HDFS daemons is deprecated.
WARNING: Attempting to execute replacement “hdfs --workers --daemon start” instead.

[root@hadoop102 hadoop-3.1.4]# hdfs --workers --daemon start

[root@hadoop102 zookeeper-3.4.10]# jpsall
=============== 192.168.1.102 ===============
14208 QuorumPeerMain
13941 JournalNode
14255 Jps
=============== 192.168.1.103 ===============
13249 QuorumPeerMain
13174 JournalNode
13287 Jps
=============== 192.168.1.104 ===============
13280 Jps
13251 QuorumPeerMain
13175 JournalNode

6、格式化

[root@hadoop102 hadoop-3.1.4]# bin/hdfs namenode -format

7、启动namenode

[root@hadoop102 hadoop-3.1.4]# hdfs -daemon start

出错，暂停[root@hadoop102 hadoop-3.1.4]# hdfs --workers --daemon stop（需要继续操作）

8、hadoop103拉取namenode

[root@hadoop103 hadoop-3.1.4]#bin/hdfs namenode -bootstrapStandby

9、hadoop103启动

[root@hadoop103 hadoop-3.1.4]#sbin/hadoop-daemon.sh start namenode

[root@hadoop103 hadoop-3.1.4]#sbin/hadoop-daemon.sh start datanode

10、手动standb切换,将nn1切换为active模式

[root@hadoop102 hadoop-3.1.4]#bin/hdfs haadmin transitionToActive nn1

自动故障转移测试

修改core-site.xml

fs.defaultFS hdfs://mycluster hadoop.tmp.dir /opt/module/ha/hadoop-3.1.4/data ha.zookeeper.quorm hadoop102:2181,hadoop103:2181,hadoop104:2181

修改hdfs-site.xml

dfs.nameservices mycluster dfs.ha.namenode.mycluster nn1,nn2 dfs.namenode.rpc-address.mycluster.nn1 hadoop102:9000 dfs.namenode.rpc-address.mycluster.nn2 hadoop102:9000 dfs.namenode.http-address.mycluster.nn1 hadoop102:50070 dfs.namenode.http-address.mycluster.nn2 hadoop102:50070

             dfs.namenode.shared.edits.dirqjournal://hadoop102:8485;hadoop103:8485;hadoop104:8485/myclusterdfs.ha.fencing.methodssshfencedfs.ha.fencing.ss.private-key-files/root/.ssh/id_rsadfs.journalnode.edits.dir/opt/module/ha/hadoop-3.1.4/data/jndfs.permissions.enablefalsedfs.client.failover.proxy.provider.myclusterorg.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProviderdfs.ha.automatic-failover.enabledtrue

分发etc

[root@hadoop102 hadoop-3.1.4]# xsync etc/

启动QJM集群

[root@hadoop102 hadoop-3.1.4]# hdfs --workers --daemon start

格式化，记得删除data和logs

???Re-format filesystem in Storage Directory root= /opt/module/hadoop-3.1.4/data/dfs/name; location= null ? (Y or N)

[root@hadoop102 hadoop-3.1.4]# bin/hdfs namenode -format

初始化HA在Zookeeper中的状态

[root@hadoop102 hadoop-3.1.4]# bin/hdfs zkfc -formatZK

同步

[root@hadoop103 hadoop-3.1.4]#bin/hdfs namenode -bootstrapStandby

启动HDFS服务

[root@hadoop102 hadoop-3.1.4]# sbin/start-dfs.sh

namenode启

[root@hadoop103 hadoop-3.1.4]#sbin/hadoop-daemon.sh start namenode

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