1.HA架构注意事项
- 两个Namenode节点在某个时间只能有一个节点正常响应客户端请求，响应请求的节点状态必须是active
- standby状态要能够快速无缝切换成active状态，两个NN节点必须时刻保持元数据一致
- 将edits文件放到qjournal(一种分布式应用，依赖zookeeper实现，管理edits)，而不存储在两个NN上，如果各个edits放在各个NN上，只能通过网络通信达到同步效果，可用性、安全性大大降低
- 每个namenode有一个监控进程zkfc，用来监控namenode是否异常
- 避免状态切换时发生brain split，执行自定义脚本杀死NN进程，确保只有一个NN是active状态
- 两个NN组成Federation
2.搭建准备
准备七台机器
3.安装过程
在CentOS7One机器上安装jdk、hadoop的过程不再赘述，参考本文
首先配置免密
CentOS7One需要免密连接CentOS7Five,CentOS7Six,CentOS7Seven，用以启动zookeeper,datanode
CentOS7Three需要免密连接CentOS7Five,CentOS7Six,CentOS7Seven，用以启动nodemanager
免密配置过程参考Hadoop免密钥配置
3.1 zookeeper配置
配置CentOS7Five的zoo.cfg
# The number of milliseconds of each tick
tickTime=2000
# The number of ticks that the initial
# synchronization phase can take
initLimit=10
# The number of ticks that can pass between
# sending a request and getting an acknowledgement
syncLimit=5
# the directory where the snapshot is stored.
# do not use /tmp for storage, /tmp here is just
# example sakes.
dataDir=/opt/zkdata
dataLogDir=/opt/zkdatalog
# the port at which the clients will connect
clientPort=2181
# the maximum number of client connections.
# increase this if you need to handle more clients
#maxClientCnxns=60
#
# Be sure to read the maintenance section of the
# administrator guide before turning on autopurge.
#
# http://zookeeper.apache.org/doc/current/zookeeperAdmin.html#sc_maintenance
#
# The number of snapshots to retain in dataDir
#autopurge.snapRetainCount=3
# Purge task interval in hours
# Set to "0" to disable auto purge feature
#autopurge.purgeInterval=1
server.4=192.168.94.142:2888:3888
server.5=192.168.94.143:2888:3888
server.6=192.168.94.144:2888:3888
将配置好的zookeeper复制到CentOS7Six,CentOS7Seven
scp /opt/zookeeper/zookeeper-3.4.10 CentOS7Six:/opt/zookeeper/zookeeper-3.4.10
scp /opt/zookeeper/zookeeper-3.4.10 CentOS7Seven:/opt/zookeeper/zookeeper-3.4.10
3.2 hadoop配置
编辑CentOS7One的core-site.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>fs.defaultFS</name>
<value>hdfs://ns1/</value>
</property>
<property>
<name>hadoop.tmp.dir</name>
<value>/usr/local/hadoop-2.6.5/data</value>
</property>
<property>
<name>ha.zookeeper.quorum</name>
<value>CentOS7Five:2181,CentOS7Six:2181,CentOS7Seven:2181</value>
</property>
</configuration>
编辑CentOS7One的hdfs-site.xml
<?xml version="1.0" encoding="UTF-8"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<!-- Put site-specific property overrides in this file. -->
<configuration>
<!--指定hdfs的nameservice为ns1，需要和core-site.xml中的保持一致 -->
<property>
<name>dfs.nameservices</name>
<value>ns1</value>
</property>
<!-- ns1下面有两个NameNode，分别是nn1，nn2 -->
<property>
<name>dfs.ha.namenodes.ns1</name>
<value>nn1,nn2</value>
</property>
<!-- nn1的RPC通信地址 -->
<property>
<name>dfs.namenode.rpc-address.ns1.nn1</name>
<value>CentOS7One:9000</value>
</property>
<!-- nn1的http通信地址 -->
<property>
<name>dfs.namenode.http-address.ns1.nn1</name>
<value>CentOS7One:50070</value>
</property>
<!-- nn2的RPC通信地址 -->
<property>
<name>dfs.namenode.rpc-address.ns1.nn2</name>
<value>CentOS7Two:9000</value>
</property>
<!-- nn2的http通信地址 -->
<property>
<name>dfs.namenode.http-address.ns1.nn2</name>
<value>CentOS7Two:50070</value>
</property>
<!-- 指定NameNode的元数据在JournalNode上的存放位置 -->
<property>
<name>dfs.namenode.shared.edits.dir</name>
<value>qjournal://CentOS7Five:8485;CentoS7Six:8485;CentOS7Seven:8485/ns1</value>
</property>
<!-- 指定JournalNode在本地磁盘存放数据的位置 -->
<property>
<name>dfs.journalnode.edits.dir</name>
<value>/usr/local/hadoop-2.6.5/journaldata</value>
</property>
<!-- 开启NameNode失败自动切换 -->
<property>
<name>dfs.ha.automatic-failover.enabled</name>
<value>true</value>
</property>
<!-- 配置失败自动切换实现方式 -->
<property>
<name>dfs.client.failover.proxy.provider.ns1</name>
<value>org.apache.hadoop.hdfs.server.namenode.ha.ConfiguredFailoverProxyProvider</value>
</property>
<!-- 配置隔离机制方法，多个机制用换行分割，即每个机制暂用一行-->
<property>
<name>dfs.ha.fencing.methods</name>
<value>
sshfence
shell(/bin/true)
</value>
</property>
<!-- 使用sshfence隔离机制时需要ssh免登陆 -->
<property>
<name>dfs.ha.fencing.ssh.private-key-files</name>
<value>/root/.ssh/id_rsa</value>
</property>
<!-- 配置sshfence隔离机制超时时间 -->
<property>
<name>dfs.ha.fencing.ssh.connect-timeout</name>
<value>30000</value>
</property>
</configuration>
编辑CentOS7One的mapred-site.xml
<?xml version="1.0"?>
<?xml-stylesheet type="text/xsl" href="configuration.xsl"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<!-- Put site-specific property overrides in this file. -->
<configuration>
<property>
<name>mapreduce.framework.name</name>
<value>yarn</value>
</property>
</configuration>
编辑CentOS7One的yarn-site.xml
<?xml version="1.0"?>
<!--
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License. See accompanying LICENSE file.
-->
<configuration>
<!-- 开启RM高可用 -->
<property>
<name>yarn.resourcemanager.ha.enabled</name>
<value>true</value>
</property>
<!-- 指定RM的cluster id -->
<property>
<name>yarn.resourcemanager.cluster-id</name>
<value>yrc</value>
</property>
<!-- 指定RM的名字 -->
<property>
<name>yarn.resourcemanager.ha.rm-ids</name>
<value>rm1,rm2</value>
</property>
<!-- 分别指定RM的地址 -->
<property>
<name>yarn.resourcemanager.hostname.rm1</name>
<value>CentOS7Three</value>
</property>
<property>
<name>yarn.resourcemanager.hostname.rm2</name>
<value>CentOS7Four</value>
"yarn-site.xml" 52L, 1479C
<name>yarn.resourcemanager.hostname.rm2</name>
<value>CentOS7Four</value>
</property>
<!-- 指定zk集群地址 -->
<property>
<name>yarn.resourcemanager.zk-address</name>
<value>CentOS7Five:2181,CentOS7Six:2181,CentOS7Seven:2181</value>
</property>
<property>
<name>yarn.nodemanager.aux-services</name>
<value>mapreduce_shuffle</value>
</property>
</configuration>
将配置好的Hadoop发送给所有机器
scp -r /usr/local/hadoop-2.6.5 CentOS7Two:/usr/local/hadoop-2.6.5/
scp -r /usr/local/hadoop-2.6.5 CentOS7Three:/usr/local/hadoop-2.6.5/
scp -r /usr/local/hadoop-2.6.5 CentOS7Four:/usr/local/hadoop-2.6.5/
scp -r /usr/local/hadoop-2.6.5 CentOS7Five:/usr/local/hadoop-2.6.5/
scp -r /usr/local/hadoop-2.6.5 CentOS7Six:/usr/local/hadoop-2.6.5/
scp -r /usr/local/hadoop-2.6.5 CentOS7Seven:/usr/local/hadoop-2.6.5/
至此，配置完毕
4.启动流程
在CentOS7Five,CentOS7Six,CentOS7Seven启动zookeeper
sh zkServer.sh start
在CentOS7Five,CentOS7Six,CentOS7Seven启动journalnode
sh hadoop-daemon.sh start journalnode
在CentOS7One上格式化namenode（以后启动无需格式化）
hdfs namenode -format
在CentOS7One上格式化 ZKFC（以后启动无需格式化）
hdfs zkfc -formatZK
在CentOS7One上启动hdfs
sh start-dfs.sh
在CentOS7Three,CentOS7Four上启动yarn
sh start-yarn.sh
5.结果
CentOS7One启动成功应该有如下进程
[root@CentOS7One ~]# jps
17397 DFSZKFailoverController
17111 NameNode
17480 Jps
CentOS7Two
[root@CentOS7Two ~]# jps
2497 Jps
2398 DFSZKFailoverController
2335 NameNode
CentOS7Three
[root@CentOS7Three ~]# jps
2344 ResourceManager
2619 Jps
CentOS7Four
[root@CentOS7Four ~]# jps
2344 ResourceManager
2619 Jps
CentOS7Five
[root@CentOS7Five logs]# jps
2803 Jps
2310 QuorumPeerMain
2460 JournalNode
2668 NodeManager
2543 DataNode
CentOS7Six
[root@CentOS7Six ~]# jps
2400 JournalNode
2608 NodeManager
2483 DataNode
2743 Jps
2301 QuorumPeerMain
CentOS7Seven
[root@CentOS7Seven ~]# jps
2768 Jps
2313 QuorumPeerMain
2425 JournalNode
2650 NodeManager
2525 DataNode
访问http://centos7one:50070，可以看到我们有三个datanode
访问http://centos7three:8088/
查看集群情况
6.致谢
https://www.cnblogs.com/biehongli/p/7660310.html
https://www.bilibili.com/video/av15390641/?p=44
7.常见问题
7.1 备用Namenode启动失败
原因：主节点格式化后备用节点的data目录还是原来的
解决：主节点格式化之后要将主节点data目录复制给备用
sh /usr/local/hadoop-2.6.5/hadoop-2.6.5/bin/hadoop namenode -format scp -r /usr/local/hadoop-2.6.5/data/ CentOS7Two:/usr/local/hadoop-2.6.5/