不多说，直接上干货！
首先，
那么，你也许，第一感觉，是想到的是
全网最详细的Hadoop HA集群启动后，两个namenode都是standby的解决办法（图文详解）
这里，nn1，不多赘述了。很简单，大家自行去看。
总的是nn，我的bigdata-pro01.kfk.com是nn1，我的bigdata-pro02.kfk.com是nn2。
是因为，在配置文件上，如下：
[kfk@bigdata-pro02 hadoop-2.6.0]$ bin/hdfs haadmin -transitionToActive nn1 Automatic failover is enabled for NameNode at bigdata-pro02.kfk.com/192.168.80.152:8020 Refusing to manually manage HA state, since it may cause a split-brain scenario or other incorrect state. If you are very sure you know what you are doing, please specify the forcemanual flag. [kfk@bigdata-pro02 hadoop-2.6.0]$
解决办法：
是因为开启了zkfc 自动选active的namenode 不能手动切换了 zkfc会自动选择namenode节点作为active的。
所以，
启动并测试
1、先停止掉Hadoop和zookeeper的进程。
2、启动zookeeper进程。
3、开启zkfc进程
[kfk@bigdata-pro01 hadoop-2.6.0]$ pwd /opt/modules/hadoop-2.6.0 [kfk@bigdata-pro01 hadoop-2.6.0]$ sbin/hadoop-daemon.sh start zkfc starting zkfc, logging to /opt/modules/hadoop-2.6.0/logs/hadoop-kfk-zkfc-bigdata-pro01.kfk.com.out
4、进入Hadoop的安装目录下面的sbin目录中，找到start-dfs.sh命令可以启动NameNode，当然这里需要你在配置了NameNode主节点的Hadoop节点上面来执行他。
或者，直接sbin/start-all.sh
[kfk@bigdata-pro02 hadoop-2.6.0]$ bin/hdfs -help
Usage: hdfs [--config confdir] COMMAND
where COMMAND is one of:
dfs run a filesystem command on the file systems supported in Hadoop.
namenode -format format the DFS filesystem
secondarynamenode run the DFS secondary namenode
namenode run the DFS namenode
journalnode run the DFS journalnode
zkfc run the ZK Failover Controller daemon
datanode run a DFS datanode
dfsadmin run a DFS admin client
haadmin run a DFS HA admin client
fsck run a DFS filesystem checking utility
balancer run a cluster balancing utility
jmxget get JMX exported values from NameNode or DataNode.
mover run a utility to move block replicas across
storage types
oiv apply the offline fsimage viewer to an fsimage
oiv_legacy apply the offline fsimage viewer to an legacy fsimage
oev apply the offline edits viewer to an edits file
fetchdt fetch a delegation token from the NameNode
getconf get config values from configuration
groups get the groups which users belong to
snapshotDiff diff two snapshots of a directory or diff the
current directory contents with a snapshot
lsSnapshottableDir list all snapshottable dirs owned by the current user
Use -help to see options
portmap run a portmap service
nfs3 run an NFS version 3 gateway
cacheadmin configure the HDFS cache
crypto configure HDFS encryption zones
storagepolicies get all the existing block storage policies
version print the version
Most commands print help when invoked w/o parameters.
[kfk@bigdata-pro02 hadoop-2.6.0]$
[kfk@bigdata-pro02 hadoop-2.6.0]$ bin/hdfs haadmin -help
Usage: DFSHAAdmin [-ns <nameserviceId>]
[-transitionToActive <serviceId> [--forceactive]]
[-transitionToStandby <serviceId>]
[-failover [--forcefence] [--forceactive] <serviceId> <serviceId>]
[-getServiceState <serviceId>]
[-checkHealth <serviceId>]
[-help <command>]
Generic options supported are
-conf <configuration file> specify an application configuration file
-D <property=value> use value for given property
-fs <local|namenode:port> specify a namenode
-jt <local|resourcemanager:port> specify a ResourceManager
-files <comma separated list of files> specify comma separated files to be copied to the map reduce cluster
-libjars <comma separated list of jars> specify comma separated jar files to include in the classpath.
-archives <comma separated list of archives> specify comma separated archives to be unarchived on the compute machines.
The general command line syntax is
bin/hadoop command [genericOptions] [commandOptions]
[kfk@bigdata-pro02 hadoop-2.6.0]$
注意，其实自带的命令里，都提供了，若两者都是standby状态怎么执行。若两者都是active状态怎么执行。这里，不多赘述。
如果，还是没解决的话，则
bin/hdfs haadmin -transitionToActive nn1
同时，大家可以关注我的个人博客：
http://www.cnblogs.com/zlslch/ 和 http://www.cnblogs.com/lchzls/ http://www.cnblogs.com/sunnyDream/
详情请见：http://www.cnblogs.com/zlslch/p/7473861.html
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