Questions tagged [apache-hadoop]

Hadoop is an Apache open-source project that provides software for reliable and scalable distributed computing. The project itself includes a variety of other complementary additions.

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What are common problems around HADOOP storage?

I've been asked to lead a program to understand why our Hadoop storage is constantly near capacity. What questions should I ask? Data age, Data size? Housekeeping schedule? How do we identify the ...
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cannot access hive from spark [closed]

I am trying to install a hadoop + spark + hive cluster. I am using hadoop 3.1.2, spark 2.4.5 (scala 2.11 prebuilt with user-provided hadoop) and hive 2.3.3 (also tried 3.1.2 with the exact same ...
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hive 2.1.0 installation on windows windows with derby [migrated]

i am using Hadoop-3.1.0 and trying to install hive- 2.1.0 with derby - 10.12.1.1. the hive command is giving me the following error. I am new to Hadoop and it would be a great help to resolve this. ...
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Loading file into and out of HDFS via system call/cmd line vs using libhdfs

I am trying to implement a simple C/C++ program for the HDFS file system like word count, it takes a file from the input path puts it into HDFS (where it gets split), processed my map-reduce function ...
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What is the structure of the data that can be stored in a Hadoop Distributed File System blocks? [closed]

I have learned various theorical informations about big data and HADOOP. It is known that block in HDFS is the smallest unit of data in file system. However, I do not undrstand how the data are ...
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Processing XML via StreamXmlRecordReader and Pig in parallel

I'm trying to process a single large XML file with many records and then parse each record in parallel using AWS EMR. ...
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1answer
41 views

BERT in production

I've created a BERT model. What are the ways to do the deployment of this model? Is it possible to use it with Spark, Hadoop or Docker?
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HDFS on docker containers - is it possible?

we are using Hadoop cluster based on HDP version - 2.6.5 with ambari platform we want to know if we can use the following HDFS components on docker containers as: journal nodes ZK fail controller ...
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1answer
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Are parquet files compressed? [closed]

Parquet File Format Hadoop. Parquet, an open-source file format for Hadoop. Parquet stores nested data structures in a flat columnar format. Compared to a traditional approach where data is stored in ...
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How to push tasks to remote Hadoop/Spark cluster

I have access to a Hadoop cluster provided by a third party. Currently, I use Spark on this cluster by logging in to a Zeppelin ...
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how to run pyspark on Hadoop cluster, cache data, then read file using pandas on local machine via its URI?

I connect to a Hadoop cluster via vpn. I want to execute a script that makes sql call and saves the data to a file on the remote machine, then using its URI I want to read on my local running Jupiter ...
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How to create tensors in spark?

I have the following data stored in HDFS: each row has three columns, id, date, item, which means a person with a particular id bought a particular item on a particular date. The dataset has billions ...
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Mapreduce jobs not working in hive

I was trying to execute a query select name, count(*) from amazon where review != NULL group by name ; Number of reduce tasks not specified. Estimated ...
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Confused about testing graph

I am doing an image classification project using CNN (convolution neural network) model. I have plotted a training and validation graph. I was asked to plot a testing graph. I don’t know about testing ...
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1answer
87 views

What is the MapReduce application master?

From Hadoop The Definitive Guide The whole process is illustrated in Figure 7-1. At the highest level, there are five independent entities: • The client, which submits the MapReduce ...
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is there a step where replicated data across different Hadoop nodes “synchronize” when job done

assume there are 3 Hadoop nodes have the same 50MB file block and doing a word count job. is there a step where that 3 nodes does the job separately and "synchronize" the result when job done?
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what does “blocks” mean in the context of HDFS ecosystem? is it the same concept in the context of a single hard disk drive?

According to Hortonworks HDFS has demonstrated production scalability of up to 200 PB of storage and a single cluster of 4500 servers, supporting close to a billion files and blocks. what does ...
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Hints on my EMR Spark Cluster

I am new to Spark, in particular I am tying to find out which are the best recommended properties to set to work on a 1 master 2 slaves cluster with 10GB memory each. Do you know which are a good set ...
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Datanode not starting on Slave Nodes for Apache Hadoop+Spark Setup

I know similar questions have been asked and I already looked through a lot of them to figure out what the issue might be, but to no avail. I am a College student currently working on a Big Data ...
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1answer
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SAP HANA or Hadoop? [closed]

this is a question regarding a career choice. I am a fresher and I recently joined an MNC in Data Engineering team. There I was offered training in either Hadoop or SAP HANA. I am in doubt as to which ...
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Is there any point in learning Hadoop in 2018?

I'm a data analyst/scientist working mostly with the Python open source stack i.e. Pandas, scikit-learn, matplotlib, seaborn etc. I want to expand my toolbox and learn a distributed computing ...
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Accumulators in Spark (PySpark) without global variables?

BACKGROUND Consider the following textbook example which uses accumulators to add vectors. ...
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PySpark: java.io.EOFException

System: 1 name node, 4 cores, 16 GB RAM 1 master node, 4 cores, 16 GB RAM 6 data nodes, 4 cores, 16 GB RAM each 6 worker nodes, 4 cores, 16 GB RAM each around 5 Terabytes of storage space The data ...
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Remote sensing image data storage in hadoop hdfs [closed]

I am new to hadoop environment. anyone kindly please help me how to store the remote sensing image data in hadoop hdfs? thanks in advance
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Unable to open application master UI in spark1.6.1 in cluster mode

Hadoop cluster has 8 nodes with high availability of resource manager. Active ResourceManager is in node 3. and Standby ResourceManager in node 2. when i submit the application in cluster mode. the ...
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Communication between name node, data node and client in hadoop by analysing Packet Capturing

if I say that in hadoop cluster system... A client has 10GB data to send to name node. After analysing the "packet capturing" actually the name node doesn't divide the data for data node, ...
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Change log level of yarn?

I'd like to change the log level of yarn. For example, when I run yarn node -list, I see a line that says ...
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141 views

Are Hadoop and Python SciPy used for the same? [closed]

Right now I've been doing a bit of research because I'm quite new to Big Data world. Among several other tools or frameworks, I've read about Apache Hadoop and Python for data analysis. Specifically,...
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does storing file in hdfs parallelize it for Spark?

For Spark's RDD operations, data must be in shape of RDD or be parallelized using: ParallelizedData = sc.parallelize(data) My question is that if I store data in ...
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1answer
322 views

Best practice for developing using Spark [closed]

I am looking for any tips and best practice on how to develop applications using Spark. I currently have access to a cluster, with data as well as a version of Spark 2.1.0 on an edge node and IntelliJ ...
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1k views

Saving Large Spark ML Pipeline to HDFS

I'm having trouble saving a large (relative to spark.rpc.message.maxSize) Spark ML pipeline to HDFS. Specifically, when I try to save the model to HDFS, it gives me an error related to spark's maximum ...
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1answer
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Which one of these tasks will benefit the most from SPARK?

My company processes Data (I am only an intern). We primarily use Hadoop. We're starting to deploy spark in production. Currently we have have two jobs, we will choose just one to begin with spark. ...
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Tasks of a Yarn Process in Hadoop

I am new to big data and Apache Hadoop YARN. This picture show how Yarn runs applications: A client requests a Yarn Application. So, in a certain datanode a Container is created and the process is ...
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Hdfs Data Balance on Cluster

Im new to Big Data, so please just dont blast me. Can you explain me why HDFS works best when the file blocks are evenly spread across the cluster ?
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Hadoop - checksum while reading file from client [closed]

In hadoop , if i want to read a file from client , the class DFSInputStream enters in action. About this, my textbook says The DFSInputStream also verifies checksums for the data transferred to it ...
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331 views

Custom Writable Serialization in Hadoop [closed]

I have some questions about Custom Writable objects in Hadoop. First of all, the private instance variables of the Writable object have to be Writable? How does Hadoop handle ...
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1answer
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Yarn service parameter for pseudodistributed [closed]

I'm trying to set up Hadoop in the pseudodistributed form. So I edited the suggested xml files. In the file yarn-site.xml, I had to insert: ...
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1answer
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Hadoop and input informations divided in splits [closed]

Hadoop divides the input to a MapReduce job into fixed-size pieces called input splits, or just splits. Hadoop creates one map task for each split, which runs the user-defined map function for ...
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Why does my master node get heap memory full for inbuilt SVD API in Apache Spark during calculation of inverse of a square matrix?

I am using a three node system: Master node: $64$ GB RAM 2 slave node: $32$ GB RAM I am calculating the inverse of a square matrix using inbuilt Apache Spark function SVD. When I called SVD function ...
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1answer
100 views

Install Spark and Hadoop in the same machine [closed]

I'm trying to install Spark Apache and Hadoop in the same machine. Spark will be used to process data, and HDFS from Hadoop will be used to store data. I first started by installing spark and it ...
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Hadoop Cluster Capacity Planning [closed]

I was doing some digging to get some deeper understanding on the Capacity Planning done for setting up a Hadoop Cluster. I have a daily ~100 GB of data generated and would like to find how a Capacity ...
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216 views

How to setup a home-laptop cluster to 'practice' elasticsearch, hadoop, mesos and spark [closed]

I'd like to have elasticsearch, hadoop, mesos and spark on my home laptop (it's an 8GB with an intel i7 CPU) for practicing the setup of such frameworks and eventually to test their functions. I'm ...
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2answers
616 views

Why has Hadoop failed to become popular?

Apache Hadoop was once considered one of the tools you should have as a Data Scientist. Around 2012 to 2014, it gained the popularity steeply among Data Scientists, and seemed to be considered one of ...
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Are jobs the only way out for data scientists? [closed]

I have reached this point in my data sceince journey that I am left wondering if jobs are the only way out for me... I am highly skilled in Hadoop, Machine Learning and now getting into Deep Learning ...
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1answer
86 views

what ETL technique should i use for text documents using Hadoop?

I have a school Big Data project where basically the teacher is going to give us a large amount of text documents (from the Gutenberg project data set ) and he want us to give as output the document ...
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2answers
350 views

Can R + Hadoop overcome R's memory constraints in any case?

I am an R user and I am interested in learning/understanding how Hadoop actually works. For this I previously read about Hadoop but was not able to find a satisfactory answer for my question. Can R + ...
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1answer
142 views

Deploying models on bigdata platforms like Hadoop and Spark

Where exactly bigdata platforms fit in to a data science/ machine learning projects ? Say I have a large dataset for a binary classification problem - cats and dogs. Now I need to create a model for ...
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1answer
931 views

Ingestion of periodic REST API Calls into Hadoop [closed]

We are planning to use REST API calls to ingest data from an endpoint and store the data to HDFS. The REST calls are done in a periodic fashion (daily or maybe hourly). I've already done Twitter ...
2
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1answer
189 views

K-means clustering on big data stored on multiple nodes on HDFS

I have a very basic question about how the k-means clustering algorithm works when the data is stored in HDFS. Does the training take place on the subset of data on each node for a fixed value of K( ...
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2answers
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How many people can use a single Hadoop cluster at one time?

I would like to know how many people can use a single Hadoop cluster at one time? I am asking because I need to figure out whether or not a single 5 or 10 node cluster would be sufficient to host a ...