“`”<\/p>\n
<strong>MapReducer\u5de5\u4f5c\u8fc7\u7a0b<\/strong><\/p>\n
<ul>
\n<li>\u9996\u5148map task\u4f1a\u4ece\u672c\u5730\u6587\u4ef6\u7cfb\u7edf\u8bfb\u53d6\u6570\u636e\uff0c\u8f6c\u6362\u6210key-value\u5f62\u5f0f\u7684\u952e\u503c\u5bf9\u96c6\u5408\uff0c\u4f7f\u7528\u7684\u662fhadoop\u5185\u7f6e\u7684\u6570\u636e\u7c7b\u578b\uff0c\u6bd4\u5982longwritable\u3001text\u7b49\uff1b<\/li>
\n<li>\u5c06\u952e\u503c\u5bf9\u96c6\u5408\u8f93\u5165mapper\u8fdb\u884c\u4e1a\u52a1\u5904\u7406\u8fc7\u7a0b\uff0c\u5c06\u5176\u8f6c\u6362\u6210\u9700\u8981\u7684key-value\u5728\u8f93\u51fa\u4e4b\u540e\u4f1a\u8fdb\u884c\u4e00\u4e2apartition\u5206\u533a\u64cd\u4f5c\uff0c\u9ed8\u8ba4\u4f7f\u7528\u7684\u662fhashpartitioner\uff0c\u53ef\u4ee5\u901a\u8fc7\u91cd\u5199hashpartitioner\u7684getpartition\u65b9\u6cd5\u6765\u81ea\u5b9a\u4e49\u5206\u533a\u89c4\u5219\uff1b<\/li>
\n<li>\u4e4b\u540e\u4f1a\u5bf9key\u8fdb\u884c\u8fdb\u884csort\u6392\u5e8f\uff0cgrouping\u5206\u7ec4\u64cd\u4f5c\u5c06\u76f8\u540ckey\u7684value\u5408\u5e76\u5206\u7ec4\u8f93\u51fa\uff0c\u5728\u8fd9\u91cc\u53ef\u4ee5\u4f7f\u7528\u81ea\u5b9a\u4e49\u7684\u6570\u636e\u7c7b\u578b\uff0c\u91cd\u5199WritableComparator\u7684Comparator\u65b9\u6cd5\u6765\u81ea\u5b9a\u4e49\u6392\u5e8f\u89c4\u5219\uff0c\u91cd\u5199RawComparator\u7684compara\u65b9\u6cd5\u6765\u81ea\u5b9a\u4e49\u5206\u7ec4\u89c4\u5219<\/li>
\n<li>\u4e4b\u540e\u8fdb\u884c\u4e00\u4e2acombiner\u5f52\u7ea6\u64cd\u4f5c\uff0c\u5176\u5b9e\u5c31\u662f\u4e00\u4e2a\u672c\u5730\u6bb5\u7684reduce\u9884\u5904\u7406\uff0c\u4ee5\u51cf\u5c0f\u540e\u9762shufle\u548creducer\u7684\u5de5\u4f5c\u91cf<\/li>
\n<li>reduce task\u4f1a\u901a\u8fc7\u7f51\u7edc\u5c06\u5404\u4e2a\u6570\u636e\u6536\u96c6\u8fdb\u884creduce\u5904\u7406\uff0c\u6700\u540e\u5c06\u6570\u636e\u4fdd\u5b58\u6216\u8005\u663e\u793a\uff0c\u7ed3\u675f\u6574\u4e2ajoin<\/li>
\n<\/ul><\/p>\n
<strong>hadoop\u67b6\u6784<\/strong><\/p>\n
<ul>
\n<li>Namenode\uff1a\u4e5f\u53eb\u540d\u79f0\u8282\u70b9\uff0c\u662fHDFS\u7684\u5b88\u62a4\u7a0b\u5e8f\uff08\u4e00\u4e2a\u6838\u5fc3\u7a0b\u5e8f\uff09\uff0c\u5bf9\u6574\u4e2a\u5206\u5e03\u5f0f\u6587\u4ef6\u7cfb\u7edf\u8fdb\u884c\u603b\u63a7\u5236\uff0c\u4f1a\u7eaa\u5f55\u6240\u6709\u7684\u5143\u6570\u636e\u5206\u5e03\u5b58\u50a8\u7684\u72b6\u6001\u4fe1\u606f\uff0c\u6bd4\u5982\u6587\u4ef6\u662f\u5982\u4f55\u5206\u5272\u6210\u6570\u636e\u5757\u7684\uff0c\u4ee5\u53ca\u8fd9\u4e9b\u6570\u636e\u5757\u88ab\u5b58\u50a8\u5230\u54ea\u4e9b\u8282\u70b9\u4e0a\uff0c\u8fd8\u6709\u5bf9\u5185\u5b58\u548cI\/O\u8fdb\u884c\u96c6\u4e2d\u7ba1\u7406\uff0c\u7528\u6237\u9996\u5148\u4f1a\u8bbf\u95eeNamenode\uff0c\u901a\u8fc7\u8be5\u603b\u63a7\u8282\u70b9\u83b7\u53d6\u6587\u4ef6\u5206\u5e03\u7684\u72b6\u6001\u4fe1\u606f\uff0c\u627e\u5230\u6587\u4ef6\u5206\u5e03\u5230\u4e86\u54ea\u4e9b\u6570\u636e\u8282\u70b9\uff0c\u7136\u540e\u5728\u548c\u8fd9\u4e9b\u8282\u70b9\u6253\u4ea4\u9053\uff0c\u628a\u6587\u4ef6\u62ff\u5230\u3002\u6545\u8fd9\u662f\u4e00\u4e2a\u6838\u5fc3\u8282\u70b9\u3002
\n <strong>\u4e0d\u8fc7\u8fd9\u662f\u4e2a\u5355\u70b9\uff0c\u53d1\u751f\u6545\u969c\u5c06\u4f7f\u96c6\u7fa4\u5d29\u6e83\u3002<\/strong>
\n<\/li>
\n<li>Secondary Namenode\uff1a\u8f85\u52a9\u540d\u79f0\u8282\u70b9\uff0c\u6216\u8005\u68c0\u67e5\u70b9\u8282\u70b9\uff0c\u5b83\u662f\u76d1\u63a7HDFS\u72b6\u6001\u7684\u8f85\u52a9\u540e\u53f0\u7a0b\u5e8f\uff0c\u53ef\u4ee5\u4fdd\u5b58\u540d\u79f0\u8282\u70b9\u7684\u526f\u672c\uff0c\u6545\u6bcf\u4e2a\u96c6\u7fa4\u90fd\u6709\u4e00\u4e2a\uff0c\u5b83\u4e0eNameNode\u8fdb\u884c\u901a\u8baf\uff0c\u5b9a\u671f\u4fdd\u5b58HDFS\u5143\u6570\u636e\u5feb\u7167\u3002NameNode\u6545\u969c\u53ef\u4ee5\u4f5c\u4e3a\u5907\u7528NameNode\u4f7f\u7528\uff0c\u76ee\u524d\u8fd8\u4e0d\u80fd\u81ea\u52a8\u5207\u6362\u3002\u4f46\u662f\u529f\u80fd\u7edd\u4e0d\u4ec5\u9650\u4e8e\u6b64\u3002\u6240\u8c13\u540e\u5907\u4e5f\u4e0d\u662f\u5b83\u7684\u4e3b\u8981\u529f\u80fd\u3002\u540e\u7eed\u8be6\u7ec6\u89e3\u91ca\u3002
\n<\/li>
\n<li>DataNode\uff1a\u53eb\u6570\u636e\u8282\u70b9\uff0c\u6bcf\u53f0\u4ece\u670d\u52a1\u5668\u8282\u70b9\u90fd\u8fd0\u884c\u4e00\u4e2a\uff0c\u8d1f\u8d23\u628aHDFS\u6570\u636e\u5757\u8bfb\u3001\u5199\u5230\u672c\u5730\u6587\u4ef6\u7cfb\u7edf\u3002\u8fd9\u4e09\u4e2a\u4e1c\u897f\u7ec4\u6210\u4e86Hadoop\u5e73\u53f0\u5176\u4e2d\u4e00\u4e2a\u652f\u67f1\u2014\u2014HDFS\u4f53\u7cfb\u3002
\n<\/li>
\n<li>JobTracker\uff1a\u53eb\u4f5c\u4e1a\u8ddf\u8e2a\u5668\uff0c\u8fd0\u884c\u5230\u4e3b\u8282\u70b9\uff08Namenode\uff09\u4e0a\u7684\u4e00\u4e2a\u5f88\u91cd\u8981\u7684\u8fdb\u7a0b\uff0c\u662fMapReduce\u4f53\u7cfb\u7684\u8c03\u5ea6\u5668\u3002\u7528\u4e8e\u5904\u7406\u4f5c\u4e1a\uff08\u7528\u6237\u63d0\u4ea4\u7684\u4ee3\u7801\uff09\u7684\u540e\u53f0\u7a0b\u5e8f\uff0c\u51b3\u5b9a\u6709\u54ea\u4e9b\u6587\u4ef6\u53c2\u4e0e\u4f5c\u4e1a\u7684\u5904\u7406\uff0c\u7136\u540e\u628a\u4f5c\u4e1a\u5207\u5272\u6210\u4e3a\u4e00\u4e2a\u4e2a\u7684\u5c0ftask\uff0c\u5e76\u628a\u5b83\u4eec\u5206\u914d\u5230\u6240\u9700\u8981\u7684\u6570\u636e\u6240\u5728\u7684\u5b50\u8282\u70b9\u3002
\n Hadoop\u7684\u539f\u5219\u5c31\u662f\u5c31\u8fd1\u8fd0\u884c\uff0c\u6570\u636e\u548c\u7a0b\u5e8f\u8981\u5728\u540c\u4e00\u4e2a\u7269\u7406\u8282\u70b9\u91cc\uff0c\u6570\u636e\u5728\u54ea\u91cc\uff0c\u7a0b\u5e8f\u5c31\u8dd1\u53bb\u54ea\u91cc\u8fd0\u884c\u3002\u8fd9\u4e2a\u5de5\u4f5c\u662fJobTracker\u505a\u7684\uff0c\u76d1\u63a7task\uff0c\u8fd8\u4f1a\u91cd\u542f\u5931\u8d25\u7684task\uff08\u4e8e\u4e0d\u540c\u7684\u8282\u70b9\uff09\uff0c\u6bcf\u4e2a\u96c6\u7fa4\u53ea\u6709\u552f\u4e00\u4e00\u4e2aJobTracker\uff0c\u7c7b\u4f3c\u5355\u70b9\u7684nn\uff0c\u4f4d\u4e8eMaster\u8282\u70b9\uff08\u7a0d\u540e\u89e3\u91caMaster\u8282\u70b9\u548cslave\u8282\u70b9\uff09\u3002
\n<\/li>
\n<li>TaskTracker\uff1a\u53eb\u4efb\u52a1\u8ddf\u8e2a\u5668\uff0cMapReduce\u4f53\u7cfb\u7684\u6700\u540e\u4e00\u4e2a\u540e\u53f0\u8fdb\u7a0b\uff0c\u4f4d\u4e8e\u6bcf\u4e2aslave\u8282\u70b9\u4e0a\uff0c\u4e0edatanode\u7ed3\u5408\uff08\u4ee3\u7801\u4e0e\u6570\u636e\u4e00\u8d77\u7684\u539f\u5219\uff09\uff0c\u7ba1\u7406\u5404\u81ea\u8282\u70b9\u4e0a\u7684task\uff08\u7531jobtracker\u5206\u914d\uff09\uff0c\u6bcf\u4e2a\u8282\u70b9\u53ea\u6709\u4e00\u4e2atasktracker\uff0c\u4f46\u4e00\u4e2atasktracker\u53ef\u4ee5\u542f\u52a8\u591a\u4e2aJVM\uff0c\u7528\u4e8e\u5e76\u884c\u6267\u884cmap\u6216reduce\u4efb\u52a1\uff0c\u5b83\u4e0ejobtracker\u4ea4\u4e92\u901a\u4fe1\uff0c\u53ef\u4ee5\u544a\u77e5jobtracker\u5b50\u4efb\u52a1\u5b8c\u6210\u60c5\u51b5\u3002
\n<\/li>
\n<li>Master\u4e0eSlave\uff1a
\n Master\u8282\u70b9\uff1a\u8fd0\u884c\u4e86Namenode\u3001\u6216\u8005Secondary Namenode\u3001\u6216\u8005Jobtracker\u7684\u8282\u70b9\u3002\u8fd8\u6709\u6d4f\u89c8\u5668\uff08\u7528\u4e8e\u89c2\u770b\u7ba1\u7406\u754c\u9762\uff09\uff0c\u7b49\u5176\u5b83Hadoop\u5de5\u5177\u3002Master\u4e0d\u662f\u552f\u4e00\u7684\uff01
\n Slave\u8282\u70b9\uff1a\u8fd0\u884cTasktracker\u3001Datanode\u7684\u673a\u5668\u3002
\n\u00a0
\n<\/li>
\n<\/ul><\/p>\n
<pre><code> "“`
\n<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
“`” <strong>MapReducer\u5de5\u4f5c\u8fc7\u7a0b<\/strong […]<\/p>\n","protected":false},"author":7,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[101],"tags":[],"class_list":["post-47557","post","type-post","status-publish","format-standard","hentry","category-c"],"_links":{"self":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47557","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/users\/7"}],"replies":[{"embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/comments?post=47557"}],"version-history":[{"count":1,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47557\/revisions"}],"predecessor-version":[{"id":47558,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/posts\/47557\/revisions\/47558"}],"wp:attachment":[{"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/media?parent=47557"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/categories?post=47557"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/wx.kaifamiao.info\/index.php\/wp-json\/wp\/v2\/tags?post=47557"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}