In the virtual machine environment, the computer between the copy configuration of the pseudo-distributed Hadoop environment, Namenode can not start the problem!

Reason: In the original computer Configuration pseudo-distribution, has been hostname and IP bindings, so when copied to another computer, when the restart will fail, because the new computer IP is not the same as the original computer IP! Because in a different network, in NAT mode, the IP of Linux is definitely located in different network segments!!

Solution: Vi/etc/hosts The original computer's IP to the new computer's IP.

Also: When reformatting Hadoop, remove all files from the TMP directory under the original Hadoop, and then stop all processes, such as Datanode. And then

Use Hadoop namenode-format format HDFs to succeed!

Re-use start-all.sh, you can start all the nodes normally!!

To summarize: Namenode did not modify the success of the following:

1. Not formatted

2. The configuration file is not modified, the hostname hostname not changed to its own

3.hostname is not bound to IP

4.ssh Password-free login not successful

In the virtual machine environment, the computer between the copy configuration of the pseudo-distributed Hadoop environment, Namenode can not start the problem!