hadoop 不使用hostname,使用ip遇到的问题(Datanode denied communication with namenode because hostname cann)及解决方案
“Hadoopprovidesamechanismtopreventunauthorizedaccess.Usercanaddhosts.denyandhosts.allowfilestolimittheaccesstoahadoopcluster.Whenadatanodejoinsthenamenode,thenamenodewillchecktheDNSnameofthedatanode,i