this question has answer here: why write “.call(this)” @ end of javascript anonymous function? [duplicate] 4 answers what kind of design pattern , significance of using closure? (function(){ // code here }).call(this); edit then difference between above code , following this keyword still refer same object in both ways. (function(){ // code here })(); thats invoked function expression. more info here: http://benalman.com/news/2010/11/immediately-invoked-function-expression/ the purpose run code while protecting scope (so variables declared within don't leak out global scope. update call sets value of this function being applied on. without it, value set window object, there set outer scope.
i have have cloudera cdh3u4 cluster setup. have secondarynamenode daemon running on 1 of nodes. i have ensure user has root access node on cluster (for example, datanode not have other daemons running) should not able start instance of secondarynamenode daemon on node (thereby having 2 secondarynamenodes on cluster) how can achieve this? thanks in advance. add property hdfs-site.xml namedfs.secondary.http.address valuesecondarynamenode-host address or ip:50090
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