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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24 views

Word count with map reduce

Suppose we use an input file that contains the following lyrics from a famous song: We’re up all night till the sun We’re up all night to get some The input pairs for the Map phase will be the ...
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37 views

KMeans using Mapreduce in Python

I wrote a mapreduce code in python which works locally i.e., cat test_mapper |python mapper.py sort the result, and ...
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8 views

Merging and deduplicating mass amounts of data in ORC on a 24 hour interval

I have the following problem I'm looking to ideate on and looking for advice on how to think about it from a data science perspective. I'll keep the numbers small for simplicity. Day 1 I get 100 ...
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11 views

How to implement distributed deep learning on small master-slave architecture through data parallelism approach?

I am a beginner and I would like to deploy the distributed deep learning model followed by Hadoop on a toy example. Like I want to use three Personals computers (PC), one would be work as a parameter ...
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1answer
14 views

Can Single Node Hadoop Cluster be installed on a system with 1gb RAM

I am trying to learn hadoop, would like to know if for basic single node installation 1gb RAM system would be enough or we need more RAM. It would be helpful if someone can share what other minimum ...
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71 views

Apache NIfi Classpath for custom jar

When NIFI is used to push data via the Azure Datalakes HDFS interface, one needs to add the respecitve hadoop-azure-datalake-3.3.0.jar file like described in the ...
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1answer
83 views

How to run unmodified Python program on GPU servers with scheduled GPUs?

Say I have one server with 10 GPUs. I have a python program which detects available GPU and use all of them. I have a couple of users who will run python (Machine learning or data mining) programs and ...
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1answer
217 views

What is the main difference between Hadoop and Spark? [closed]

I recently read the following about Hadoop vs. Spark: Insist upon in-memory columnar data querying. This was the killer-feature that let Apache Spark run in seconds the queries that would take Hadoop ...
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1answer
140 views

Hive / Impala best practice code structuring

Coming from a DWH-background I am used to putting subqueries almost everywhere in my queries. On a Hadoop project (with Hive version 1.1.0 on Cloudera), I noticed we can forego subqueries in some ...
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1answer
19 views

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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999 views

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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31 views

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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14 views

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
274 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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1answer
3k views

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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58 views

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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0answers
141 views

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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238 views

Mapreduce jobs not working in hive

I was trying to execute a hive query: select name, count(*) from amazon where review != NULL group by name ; Number of reduce tasks not specified. Estimated ...
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2answers
760 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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1answer
17 views

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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548 views

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
56 views

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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1answer
395 views

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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2answers
3k views

Accumulators in Spark (PySpark) without global variables?

BACKGROUND Consider the following textbook example which uses accumulators to add vectors. ...
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2answers
6k views

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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0answers
22 views

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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96 views

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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0answers
492 views

Communication between name node, data node and client in hadoop by analysing Packet Capturing [closed]

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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128 views

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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2answers
184 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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1answer
55 views

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 ...
2
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1answer
365 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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1answer
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
57 views

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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101 views

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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32 views

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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295 views

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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0answers
361 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
21 views

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
46 views

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 ...
2
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0answers
75 views

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
127 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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0answers
288 views

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 ...
3
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0answers
223 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 ...
2
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2answers
650 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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0answers
76 views

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
139 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
380 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
253 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
1k 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 ...