Hadoop 2.3.0-cdh5.0.2升级Hadoop 2.5.0-cdh5.3.1，

Hadoop 2.3.0-cdh5.0.2升级Hadoop 2.5.0-cdh5.3.1，

一、准备升级包 for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;ssh $line "/bin/mkdir /home/hadoop/platform";done
for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;scp /home/hadoop/platform/hadoop-2.5.0-cdh5.3.3.tar.gz hadoop@$line:/home/hadoop/platform;done

for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;ssh $line "/bin/tar -zvxf /home/hadoop/platform/hadoop-2.5.0-cdh5.3.3.tar.gz -C /home/hadoop/platform/";done
二、做好文件备份信息：
 a、备份namenode信息，即etc/hadoop/hdfs-site.xml下的dfs.namenode.name.dir所指向的文件夹
 cp -r /data/tmp/dfs/name .


 b、备份config文件：hadoop-env.sh，yarn-env.sh，core-site.xml，mapred-site.xml，hdfs-site.xml，yarn-site.xml
cp -r $HADOOP_CONF_DIR .

c、文件信息 hadoop fsck / -files -blocks -locations > dfs-v-old-fsck-1.log hadoop dfs -lsr / > dfs-v-old-lsr-1.log hadoop dfsadmin -report > dfs-v-old-report-1.log
三、将原来的hadoop备份一下，防止升级失败回滚 for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;ssh $line "/bin/cp -r /opt/hadoop /opt/hadoop2.3.0";done
四，删除原来的软连接，新建软连接到新版本的hadoop 注意：删除软连接 /opt/hadoop而不是 /opt/hadoop/, for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;ssh $line "/bin/rm -rf  /opt/hadoop";done
for line in `cat /home/hadoop/platform/hadoop.list|awk '{print $1}'`; do echo $line;ssh $line "/bin/ln -s /data/platform/hadoop-2.5.0-cdh5.3.1 /opt/hadoop";done
五、创建一个FsImage hdfs dfsadmin -rollingUpgrade prepare
hdfs dfsadmin -rollingUpgrade query检查滚动Image的状态。等一会接着重新运行这个命令直到“Proceed with rolling upgrade”消息出现。   
六、执行升级命令
a、关闭standby nn1:
hadoop-daemon.sh stop namenode

b、hdfs namenode -rollingUpgrade started
c、关闭active nn2:
hadoop-daemon.sh stop namenode

d、hdfs namenode -rollingUpgrade started
e、启动所yostart-all.sh

 
遇到如下异常： File system image contains an old layout version -55. An upgrade to version -59 is required. Please restart NameNode with the "-rollingUpgrade started" option if a rolling upgrade is already started;  or restart NameNode with the "-upgrade" option to start a new upgrade.
修改： /data/platform/hadoopupgrade/name/current/VERSION layoutVersion=-55 改成layoutVersion=-59
nohup hdfs namenode -rollingUpgrade started &
datanode启动不了 最好执行回滚： start-dfs.sh -rollback
参考资料： http://blog.csdn.net/shubingzhuoxue/article/details/50085407
https://www.zybuluo.com/layor/note/161370