Re: Configure Rack Numbers
Hello, Thank you very much for this document. How can I see each data nodes belongs to which rack ? I ran the below command on namenode and it throws an error. bin/hadoop dfsadmin -printTopology Warning: $HADOOP_HOME is deprecated. printTopology: Unknown command Is there any other command to check ? Thanks & Regards, Abdul Navaz Research Assistant University of Houston Main Campus, Houston TX Ph: 281-685-0388 From: Brahma Reddy Battula Reply-To: Date: Sunday, November 16, 2014 at 11:10 PM To: "user@hadoop.apache.org" Subject: RE: Configure Rack Numbers Hi Navaz, you have to configure the following two properties in namenode(after that you need to restart the namenode). topology.node.switch.mapping.impl org.apache.hadoop.net.ScriptBasedMapping The default implementation of the DNSToSwitchMapping. It invokes a script specified in topology.script.file.name to resolve node names. If the value for topology.script.file.name is not set, the default value of DEFAULT_RACK is returned for all node names. topology.script.file.name /path/to/topo.sh The script name that should be invoked to resolve DNS names to NetworkTopology names. Example: the script would take host.foo.bar as an argument, and return /rack1 as the output. Example script file. topo.sh === #!/bin/bash python /topology.py "$@" topology.py === import sys from string import join DEFAULT_RACK = '/default/rack0'; RACK_MAP = { '208.94.2.10' : '/datacenter1/rack0', '1.2.3.4' : '/datacenter1/rack1', '1.2.3.5' : '/datacenter1/rack1', '1.2.3.6' : '/datacenter1/rack1', '10.2.3.4' : '/datacenter1/rack2', '10.2.3.4' : '/datacenter1/rack2' } if len(sys.argv)==1: print DEFAULT_RACK else: print join([RACK_MAP.get(i, DEFAULT_RACK) for i in sys.argv[1:]]," ") Please check the following link for more details. https://issues.apache.org/jira/secure/attachment/12345251/Rack_aware_HDFS_pr oposal.pdf Thanks & Regards Brahma Reddy Battula HUAWEI TECHNOLOGIES INDIA PVT.LTD. Ground,1&2 floors,Solitaire, 139/26,Amarjyoti Layout,Intermediate Ring Road,Domlur Bangalore - 560 071 , India Tel : +91- 80- 3980 9600 Ext No: 4905 Fax : +91-80-41118578 From: Abdul Navaz [navaz@gmail.com] Sent: Monday, November 17, 2014 4:48 AM To: user@hadoop.apache.org Subject: Configure Rack Numbers Hello, I have hadoop cluster with 9 nodes. All belongs to /default racks. But I want the setup something similar to this. (All are in same subnets) Rack 0: DataNode1,Datanode2,DataNode3 and top of rack switch1. Rack 1: DataNode4,Datanode5,DataNode6 and top of rack switch2. Rack 3: DataNode7,Datanode8,DataNode9 and top of rack switch3. I am trying to check the Hadoop rack awareness and how it copies the single block of data in one rack and replicas in some other rack. I want to analyse some network performance from this. So how can we separate this DNs based on rack numbers. Where can we configure this rack numbers and say this DN belongs to this rack number. Thanks & Regards, Abdul Navaz
Re: Configure Rack Numbers
The effective technique to fix block distribution after changes in rack awareness is to increase replication factor and decrease it back Regards, Serge > On Nov 16, 2014, at 21:10, Brahma Reddy Battula > wrote: > > Hi Navaz, > > you have to configure the following two properties in namenode(after that you > need to restart the namenode). > > > topology.node.switch.mapping.impl > org.apache.hadoop.net.ScriptBasedMapping >The default implementation of the DNSToSwitchMapping. It > invokes a script specified in topology.script.file.name to resolve > node names. If the value for topology.script.file.name is not set, the > default value of DEFAULT_RACK is returned for all node names. > > > > > topology.script.file.name > /path/to/topo.sh >The script name that should be invoked to resolve DNS names to > NetworkTopology names. Example: the script would take host.foo.bar as an > argument, and return /rack1 as the output. > > > > > Example script file. > > > topo.sh > === > > #!/bin/bash > > python /topology.py "$@" > > > topology.py > === > import sys > from string import join > > DEFAULT_RACK = '/default/rack0'; > > RACK_MAP = { '208.94.2.10' : '/datacenter1/rack0', > '1.2.3.4' : '/datacenter1/rack1', > '1.2.3.5' : '/datacenter1/rack1', > '1.2.3.6' : '/datacenter1/rack1', > > '10.2.3.4' : '/datacenter1/rack2', > '10.2.3.4' : '/datacenter1/rack2' > } > > if len(sys.argv)==1: > print DEFAULT_RACK > else: > print join([RACK_MAP.get(i, DEFAULT_RACK) for i in sys.argv[1:]]," ") > > > Please check the following link for more details. > > > https://issues.apache.org/jira/secure/attachment/12345251/Rack_aware_HDFS_proposal.pdf > > > > Thanks & Regards > > Brahma Reddy Battula > > > > HUAWEI TECHNOLOGIES INDIA PVT.LTD. > Ground,1&2 floors,Solitaire, > 139/26,Amarjyoti Layout,Intermediate Ring Road,Domlur > Bangalore - 560 071 , India > Tel : +91- 80- 3980 9600 Ext No: 4905 > Fax : +91-80-41118578 > > From: Abdul Navaz [navaz@gmail.com] > Sent: Monday, November 17, 2014 4:48 AM > To: user@hadoop.apache.org > Subject: Configure Rack Numbers > > Hello, > > I have hadoop cluster with 9 nodes. All belongs to /default racks. But I want > the setup something similar to this. > > (All are in same subnets) > > Rack 0: DataNode1,Datanode2,DataNode3 and top of rack switch1. > Rack 1: DataNode4,Datanode5,DataNode6 and top of rack switch2. > Rack 3: DataNode7,Datanode8,DataNode9 and top of rack switch3. > I am trying to check the Hadoop rack awareness and how it copies the single > block of data in one rack and replicas in some other rack. I want to analyse > some network performance from this. > > So how can we separate this DNs based on rack numbers. Where can we configure > this rack numbers and say this DN belongs to this rack number. > > > > Thanks & Regards, > > Abdul Navaz >
RE: Configure Rack Numbers
Hi Navaz, you have to configure the following two properties in namenode(after that you need to restart the namenode). topology.node.switch.mapping.impl org.apache.hadoop.net.ScriptBasedMapping The default implementation of the DNSToSwitchMapping. It invokes a script specified in topology.script.file.name to resolve node names. If the value for topology.script.file.name is not set, the default value of DEFAULT_RACK is returned for all node names. topology.script.file.name /path/to/topo.sh The script name that should be invoked to resolve DNS names to NetworkTopology names. Example: the script would take host.foo.bar as an argument, and return /rack1 as the output. Example script file. topo.sh === #!/bin/bash python /topology.py "$@" topology.py === import sys from string import join DEFAULT_RACK = '/default/rack0'; RACK_MAP = { '208.94.2.10' : '/datacenter1/rack0', '1.2.3.4' : '/datacenter1/rack1', '1.2.3.5' : '/datacenter1/rack1', '1.2.3.6' : '/datacenter1/rack1', '10.2.3.4' : '/datacenter1/rack2', '10.2.3.4' : '/datacenter1/rack2' } if len(sys.argv)==1: print DEFAULT_RACK else: print join([RACK_MAP.get(i, DEFAULT_RACK) for i in sys.argv[1:]]," ") Please check the following link for more details. https://issues.apache.org/jira/secure/attachment/12345251/Rack_aware_HDFS_proposal.pdf Thanks & Regards Brahma Reddy Battula HUAWEI TECHNOLOGIES INDIA PVT.LTD. Ground,1&2 floors,Solitaire, 139/26,Amarjyoti Layout,Intermediate Ring Road,Domlur Bangalore - 560 071 , India Tel : +91- 80- 3980 9600 Ext No: 4905 Fax : +91-80-41118578 From: Abdul Navaz [navaz@gmail.com] Sent: Monday, November 17, 2014 4:48 AM To: user@hadoop.apache.org Subject: Configure Rack Numbers Hello, I have hadoop cluster with 9 nodes. All belongs to /default racks. But I want the setup something similar to this. (All are in same subnets) Rack 0: DataNode1,Datanode2,DataNode3 and top of rack switch1. Rack 1: DataNode4,Datanode5,DataNode6 and top of rack switch2. Rack 3: DataNode7,Datanode8,DataNode9 and top of rack switch3. I am trying to check the Hadoop rack awareness and how it copies the single block of data in one rack and replicas in some other rack. I want to analyse some network performance from this. So how can we separate this DNs based on rack numbers. Where can we configure this rack numbers and say this DN belongs to this rack number. Thanks & Regards, Abdul Navaz