{"id":1393,"date":"2017-03-31T12:30:24","date_gmt":"2017-03-31T16:30:24","guid":{"rendered":"http:\/\/www.xavignu.com\/?p=1393"},"modified":"2017-04-18T15:24:13","modified_gmt":"2017-04-18T19:24:13","slug":"listing-namenodes-and-datanodes-in-hadoop","status":"publish","type":"post","link":"https:\/\/www.xavignu.com\/?p=1393","title":{"rendered":"Listing namenodes and datanodes in Hadoop"},"content":{"rendered":"<p>Ever wondered how to list <a href=\"http:\/\/hadoop.apache.org\/\" target=\"_blank\">Hadoop<\/a> <a href=\"https:\/\/wiki.apache.org\/hadoop\/NameNode\" target=\"_blank\">namenodes<\/a>? Quite easy as seen below.<\/p>\n<pre id=\"terminal\">hdfs getconf -namenodes\r\nhadoop02.mydomain.com hadoop01.mydomain.com\r\n<\/pre>\n<p>Now if you want to list the <a href=\"https:\/\/wiki.apache.org\/hadoop\/DataNode\" target=\"_blank\">datanodes<\/a> we do that with <a href=\"https:\/\/hadoop.apache.org\/docs\/r1.2.1\/commands_manual.html#dfsadmin\" target=\"_blank\">dfsadmin<\/a>.<\/p>\n<pre id=\"terminal\">hdfs dfsadmin  -printTopology\r\nRack: \/default\r\n   192.168.0.15:50010 (hadoop15.mydomain.com)\r\n   192.168.0.16:50010 (hadoop16.mydomain.com)\r\n   192.168.0.17:50010 (hadoop17.mydomain.com)\r\n   192.168.0.18:50010 (hadoop18.mydomain.com)\r\n   192.168.0.19:50010 (hadoop19.mydomain.com)\r\n   192.168.0.20:50010 (hadoop20.mydomain.com)\r\n   192.168.0.21:50010 (hadoop21.mydomain.com)\r\n   192.168.0.22:50010 (hadoop22.mydomain.com)\r\n   192.168.0.23:50010 (hadoop23.mydomain.com)\r\n   192.168.0.24:50010 (hadoop24.mydomain.com)\r\n\r\n<\/pre>\n<p>Above command should be executed as a user with hdfs <a href=\"https:\/\/hadoop.apache.org\/docs\/current\/hadoop-project-dist\/hadoop-hdfs\/HdfsPermissionsGuide.html#The_Super-User\" target=\"_blank\">superuser<\/a> permissions.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>Ever wondered how to list Hadoop namenodes? Quite easy as seen below. hdfs getconf -namenodes hadoop02.mydomain.com hadoop01.mydomain.com Now if you want to list the datanodes we do that with dfsadmin. hdfs dfsadmin -printTopology Rack: \/default 192.168.0.15:50010 (hadoop15.mydomain.com) 192.168.0.16:50010 (hadoop16.mydomain.com) 192.168.0.17:50010 (hadoop17.mydomain.com) 192.168.0.18:50010 (hadoop18.mydomain.com) 192.168.0.19:50010 (hadoop19.mydomain.com) 192.168.0.20:50010 (hadoop20.mydomain.com) 192.168.0.21:50010 (hadoop21.mydomain.com) 192.168.0.22:50010 (hadoop22.mydomain.com) 192.168.0.23:50010 (hadoop23.mydomain.com) 192.168.0.24:50010 (hadoop24.mydomain.com) [&hellip;]<\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"spay_email":"","jetpack_publicize_message":"","jetpack_is_tweetstorm":false,"jetpack_publicize_feature_enabled":true},"categories":[74],"tags":[81,82],"jetpack_featured_media_url":"","jetpack_publicize_connections":[],"jetpack_shortlink":"https:\/\/wp.me\/pTQgt-mt","jetpack_sharing_enabled":true,"_links":{"self":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/1393"}],"collection":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=1393"}],"version-history":[{"count":3,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/1393\/revisions"}],"predecessor-version":[{"id":1396,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=\/wp\/v2\/posts\/1393\/revisions\/1396"}],"wp:attachment":[{"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=1393"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=1393"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.xavignu.com\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=1393"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}