Trivial-about hadoop2.2.0, trivial-hadoop2.2.0

Trivial-about hadoop2.2.0, trivial-hadoop2.2.0

HDFS module functions

• Namenode: the master node that stores file metadata such as file names, file directory structures, and file attributes (generation time, number of copies, and file permissions) and the block list of each file and the datanode of the block;
• Datanode: stores file block data in the local file system and verifies the block;
• Secondary namenode: a secondary background program used to monitor the HDFS status. It obtains HDFS metadata snapshots at intervals;

 

YARN module functions

ResourceManager:

NodeManager:

ApplicationMaster:

Container:

• Abstract The running environment of a task. It encapsulates information about the running of multiple resources such as CPU and memory, environment variables, startup commands, and other tasks;

 

 

 

MR module functions

......

 

Logs

• Start the log file directory $ HADOOP_HOME/logs;
• Log format. out and. log

. Log: Most application log information recorded through log4j;

. Out: records the standard output and standard error logs, with fewer logs.

• Log naming rules

Framework name-user name-process name-host name-log format suffix

 

Notepad + FZ + SecureCRT combination is not bad

 

 

 

When the hadoop-220 is configured, execute start-dfssh to display the following, help solve

Grant hadoop users all permissions on/usr/local/hadoop

Hello, how do you configure local win7 in Eclipse to access hadoop220 under Centos?

For code access, you only need to configure the fs. default. name attribute. If you are using Eclipse to integrate the mapreduce plug-in, the main problem is the Eclispe version. You can either find a version online or try it on your own.