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Questions tagged [namenode]

The Hadoop NameNode is the centerpiece of an HDFS file system. It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept.

The NameNode is the centerpiece of an HDFS file system. It keeps the directory tree of all files in the file system, and tracks where across the cluster the file data is kept. It does not store the data of these files itself.

Client applications talk to the NameNode whenever they wish to locate a file, or when they want to add/copy/move/delete a file. The NameNode responds to the successful requests by returning a list of relevant DataNodes where the data lives.

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NameNode startup error: No FileSystem for scheme: ht

I'm in HDP 2.6. When I try to start the NameNode I get the bellow error: java.io.IOException: No FileSystem for scheme: http at org.apache.hadoop.fs.FileSystem.getFileSystemClass(FileSystem.java:2786) at…
fhe
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Trying to install hadoop on raspberry pi3, not able to start name node

Hi all I am trying to install hadoop on raspberry pi3, I am able to run all but name node,I searched all sources possible but I couldnt find any such problem elsewhere, the java version that my PI is running on is jdk.1.7 here are my configuration…
chaitanya vardhan
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HortonWorks HDP 2.6: NameNode Install issue via Ambari

I tried to install HDP V2.6 with Ambari on 3 nodes (node0.local, node1.local, node2.local), but during the installation the following NameNode failure happened on node0 : "OSError: [Errno 1] Operation not permitted:…
Enaway
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Automatic Failover not working in Hadoop

I'm trying to build a 3 node cluster (2 Namenode(nn1,nn2) and 1 datanode(dn1)) .Using Namenode WEBUI, I'm able to view that nn1 is active and nn2 is standby. however, when I kill the active nn1, standby nn2 is not going active. Please help me what…
Raj
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Clarity of terms used in HDFS?

I have come across several terms while getting familiar to HDFS. Few of the terms are like: namespace, metadata, transaction logs, fsimage, editlogs. Sometimes it appears that all these terms describe same thing, which is "having some information",…
CuriousMind
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How does Namenode reconstruct the full block information after restart?

I am trying to understand Namenode and I referred to online material and referring to book Hadoop: The definitive guide as well. I understand that Namenode has concept like : "edit logs", "fsimage", and I can see the following files in my…
CuriousMind
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Namenode not start after restart pc (hadoop 2.7.3)

i've configured hadoop 2.7.3 on ubuntu 16.04 and run all (word count and other mapReduce run all). after restart pc, i launch start-dfs, but the namenode not started. other guide says remove temporay directory, but i don't have it. that are my…
Alessio
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How does master node start all the process in a hadoop cluster?

I have set up a Hadoop cluster of 5 virtual machines , using plain vanilla Hadoop. The cluster details are below: 192.168.1.100 - Configured to Run NameNode and SNN daemons 192.168.1.101 - Configured to Run ResourceManager daemon. 192.168.1.102 -…
CuriousMind
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hadoop-1.2.1 namenode is not formatted

I have installed hadoop 1.2.1 in Ubuntu 16 and configured as below: core-site.xml fs.default.name hdfs://localhost:8020 hadoop.tmp.dir …
satish N
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Hadoop Restore from namenode and datanode files

I have the datanode, namenode and secondary namenode folder (with all data or information inside) from a a different hadoop installation. My question is, how can you see whats in there or add it to your local HDFS to see the data or information.…
PeterPa1va
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Using Consul for hadoop hdfs namenode failover

I'm trying to work with Hadoop Java Client and I'm using Consul for routing to current active name node in my cluster. My cluster is cloudera and using HA. When active namenode is changed by hadoop Consul immediately also changing resolution to new…
mixermt
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How to set the number of NameNodes, DataNodes, Mappers and Reducers in Hadoop

I want to know how to set the number of NameNodes DataNodes Mappers Reducers in code/configuration of Hadoop.
Mosab Shaheen
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how to start name node in cdh 5.5.0 version?

I started the Cloudera manager successfully but while trying to see the list of files it throws error related to namenode. After that I checked the namenode is started or not , but it says Unable to connect Firefox can't establish a…
MallikArjuna Reddy
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I want the know that (formula) how to calculate the RAM, CPU & disk memory of namenode, yarn & Resource Manager

I am trying to build the cluster on different sizes, and that is why I want the formulas from which I can calculate the RAM, CPU & disk memory of namenode, yarn & Resource Manager. also want to know that how RAM, CPU & Disk related to each other.
The Joker
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Name node is in safe mode. Not able to leave. Hadoop 2.6.0

I am new to hadoop and i am just trying to see how things work. I am following this tutorial for WordCount . But in step 9 when i execute hduser@spyros:/usr/local/hadoop/etc/hadoop$ hadoop dfs -mkdir -p /usr/local/hadoop/input I am taking this…
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