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Good Explanation!!. I have one doubt. while explaining the application flow, i didn't get from where data will come and how node manager will request for data to DataNode. Could you please clarify it. Thanks
We are super happy that Edureka is helping you learn better. Your support means a lot to us and it motivated us to create even better learning content and courses experience for you . Do subscribe the channel for more updates : ) Hit the bell icon to never miss an update from our channel : )
Hey Chetan, thanks for checking out our tutorial! MR is a fault tolerant framework. When a Map task fails (streaming API or Java API) the behaviour is the same. Once the job tracker is notified that the task has failed it will try and reschedule the task. The temporary output generated by the failed task is deleted. Hope this helps. Cheers!
hi guys ...u guys are doing a great job. keep going.my query is if i want to become a front end developer then what is the path that i have to follow.i mean the sequence of languages,technologies to be learnt....
Hey Varun, thanks for your interest. You have come to the right place if you'd like learn all about Front-end development. Here's our Full-Stack Masters Program that's tailor-made to make you proficient in skills to work with back-end and front-end web technologies: www.edureka.co/masters-program/full-stack-developer-training. It includes training on Web Development, jQuery, Angular, NodeJS, ExpressJS and MongoDB. Please feel free to contact us at +919066020868 if you need any assistance. Hope this helps. Cheers!
Hey Ridhi, thanks for checking out our tutorial. Here's an advanced MapReduce tutorial: ruclips.net/video/QOiV3jG-QTY/видео.html. Do subscribe to our channel to stay posted on upcoming tutorials. Cheers!
Hi Edureka, great videos I really enjoy it, I have a question. I followed your example and I created an input file with the data Dear bear etc... and I copied it into dfs and I can actually read it there on the DFS root... When I executed the command with wordcount... everything seems to work fine and the output folder is created but the part-r-0000 file is not created and I have a job failed as task failed failedmaps:1 failedReduce:0 any suggestions?
+M.Z Tabbara, thanks for checking out our tutorial! With regard to the error you're getting, there can be multiple reasons, for instance, some of the deamons are not running. So to get that running, please follow the below given steps: Open terminal and type sudo service hadoop-master restart ---->ENTER Then check the deamons sudo jps -----ENTER After the above commands you must get the following deamons running, [edureka@localhost ~]$ sudo jps; [sudo] password for edureka: 5840 ResourceManager 5896 NodeManager 5671 NameNode 13071 Jps 5957 JobHistoryServer 5749 DataNode [edureka@localhost ~]$ After doing the above, try to execute the map reduce code. There could also be a mistake in the dataset or in the code. Please check the dataset properly and whether the logic in the MapReduce code is fine but there is any mistake in the dataset or vice versa. For example, there could be an extra line between the rows in the dataset, etc. Hope this helps. Cheers!
hai sir please provide the other eco systems like hive ,pig,sqoop like how you provided the mapreduce and hdfs your explanation is so clear please provide other videos particularly you teached thanks a lot to edureka
Hey Naga, thanks for checking out our tutorial! We're glad we could help. You can check out tutorials on Pig, Hive etc here: ruclips.net/p/PL9ooVrP1hQOEmUPq5vhWfLYJH_b9jFBbR. Do subscribe to our channel to stay posted on upcoming videos. Cheers!
In the slide Application Workflow, there is no arrow from RM to NM. I think there is something wrong in that. As per my understanding, RM asks NM to create a container. And NM is the one who creates the container and launch an Application Master. Please correct me. I am confused.
Hey Vinod, thanks for checking out our tutorial! Please go through the below given explanation: The application startup process is the following: 1. a client submits an application to the Resource Manager 2. the Resource Manager allocates a container 3. the Resource Manager contacts the related Node Manager 4. the Node Manager launches the container 5. the Container executes the Application Master The Application Master is responsible for the execution of a single application. It asks for containers to the Resource Scheduler (Resource Manager) and executes specific programs (e.g., the main of a Java class) on the obtained containers. The Application Master knows the application logic and thus it is framework-specific. The MapReduce framework provides its own implementation of an Application Master. Hope this helps. Cheers!
Thank you so much for the response. Point 2 --> Does the Resource Manager allocates a container to the node manager?? Point 4 --> Will the node manager launch the container in the same node manager or a different one?
Hey Vinod, here are the answers to your queries: 1. Does the Resource Manager allocates a container to the node manager? No, Container is a fraction of the Node Manager capacity and it is used by the client for running a program. 2.Will the node manager launch the container in the same node manager or a different one? Yes, the node manager launches the container in the same node. NodeManager - responsible for containers launch, monitoring their resource usage (cpu, memory, disk, network) and reporting it to the ResourceManager/Scheduler. Hope this helps. Cheers!
Hey Ravi, thanks for checking out our tutorial! While these tutorials will give you an introduction and good start to Hadoop, you would be missing out on 1. Interactivity (our live classes are highly interactive) and support from the instructor. 2. Live project component because theoretical training will only help you to a certain extent. (In our course, you'll work on a live project on any of the selected use cases, involving Big Data Analytics using MapReduce, Pig, Hive, Flume and Sqoop) 3. 24X7 support, 365 days of the year, because your training does not end with the classes. Our experts will support you through real-life projects that you might take up after training. 4. Life-time access to learning material and class recordings, not to mention the opportunity to retake classes if there are upgrades to the technology. If you would like to know more, please share your contact details with us and we will arrange a call with one of our experts. Hope this helps. Cheers!
Hi Team,I am from Teradata background so wanted to check is Java essential to learn Hadoop while there are other components like PIG,Scoop,Hive to work only on database. what is the scope of java in Hadoop development projects?
Hey Ramana, thanks for checking out our tutorial. There are no pre-requisites as such to learn Hadoop. Knowledge of core Java and SQL are beneficial to learn Hadoop, but it's not mandatory. Also, we will provide you with a complimentary self-paced course on Java essentials for Hadoop when you enroll for our course to help you brush up on it so you don't need to worry. Please feel free to get in touch with us if you have any questions or concerns. If you'd like us to call and assist you, please share your contact details (we will not make the comment live) and we will get in touch with you to guide you. Alternatively, you can also get in touch with us at 8880862004 if you prefer that. Hope this helps. Cheers!
Hey Jack, sorry for the delay. NameNode is the master node of HDFS, which is the storing part of Hadoop. NameNode stores the metadata of the data stored in HDFS like which block resides in which DataNode, where are the replicas of a block are stored, etc. While ResourceManager is the master node of YARN, which is teh resource management part of Hadoop. It arbitrates all the available cluster resources and thus helps manage the distributed applications running on the YARN system. It works together with the per-node NodeManagers (NMs) and the per-application ApplicationMasters (AMs). Hope this helps!
Hey Rahul, thanks for checking out our blog. Please use the followig commands: hadoop jar filename.jar inputpathinHDFS outputpathinHDFS. Example : hadoop jar Wordcount.jar /input /output Hope this helps. Cheers!
Hey Jeet, thanks for checking out our tutorial. Here's the complete explanation: The Combiner class is used in between the Map class and the Reduce class to reduce the volume of data transfer between Map and Reduce. Usually, the output of the map task is large and the data transferred to the reduce task is high. The following MapReduce task diagram shows the COMBINER PHASE. How Combiner Works? Here is a brief summary on how MapReduce Combiner works − A combiner does not have a predefined interface and it must implement the Reducer interface’s reduce() method. A combiner operates on each map output key. It must have the same output key-value types as the Reducer class. A combiner can produce summary information from a large dataset because it replaces the original Map output. Although, Combiner is optional yet it helps segregating data into multiple groups for Reduce phase, which makes it easier to process. Also Please go through the below external link for the combiner www.tutorialspoint.com/map_reduce/map_reduce_combiners.htm Hope this helps. Cheers!
Hey Sarang, thanks for checking out our tutorial! The assignment mentioned in this tutorial is part of our Edureka course curriculum and you can access it by enrolling into our course here: www.edureka.co/big-data-and-hadoop. Please feel free to get in touch with us if you have any questions. Cheers!
Hey Rohan, thanks for checking out our tutorial. Using Hadoop MapReduce one can process large files as it allows you to divide the data into smaller chunks and process them in parallel. You can write MapReduce program using Java, C++, etc. Hope this helps. Cheers!
Got a question on the topic? Please share it in the comment section below and our experts will answer it for you. For Edureka Hadoop Training and Certification Curriculum, Visit our Website: bit.ly/2Ozdh1I
Thank you very much sri... For this wonderful explanation
quality content given for free! Might stop by eureka and purchase a complete course, love these!!!
Hi : ) We really are glad to hear this ! Truly feels good that our team is delivering and making your learning easier :) Keep learning with us .Stay connected with our channel and team :) . Do subscribe the channel for more updates : ) Hit the bell icon to never miss an update from our channel : )
one of the best explanation of MR process
Good Explanation!!. I have one doubt. while explaining the application flow, i didn't get from where data will come and how node manager will request for data to DataNode. Could you please clarify it. Thanks
you have great teaching technique !!!
Nicely explained thanks
We are super happy that Edureka is helping you learn better. Your support means a lot to us and it motivated us to create even better learning content and courses experience for you . Do subscribe the channel for more updates : ) Hit the bell icon to never miss an update from our channel : )
Thank u
Thank You for this video.
It is a great explanation ! Thanks. I have a question : What happens when one of mapper executing map-reduce job fails?
Hey Chetan, thanks for checking out our tutorial! MR is a fault tolerant framework. When a Map task fails (streaming API or Java API) the behaviour is the same. Once the job tracker is notified that the task has failed it will try and reschedule the task. The temporary output generated by the failed task is deleted. Hope this helps. Cheers!
Thanks for reply. It helps.
Excellent! Congratulations and thank you so much.
Great explanation sir!!!!
great explanation and your teachning method is good
Thanks for the compliment! Do subscribe to our channel to stay posted on upcoming tutorials.
Yes understood Matthew
well explained!
thank you very much sir
Thank you for watching our video. Do subscribe, like and share to stay connected with us. Cheers :)
hi guys ...u guys are doing a great job. keep going.my query is if i want to become a front end developer then what is the path that i have to follow.i mean the sequence of languages,technologies to be learnt....
Hey Varun, thanks for your interest. You have come to the right place if you'd like learn all about Front-end development.
Here's our Full-Stack Masters Program that's tailor-made to make you proficient in skills to work with back-end and front-end web technologies: www.edureka.co/masters-program/full-stack-developer-training. It includes training on Web Development, jQuery, Angular, NodeJS, ExpressJS and MongoDB.
Please feel free to contact us at +919066020868 if you need any assistance. Hope this helps. Cheers!
Very nice tutorial. Thanks!
Thank you for appreciating our work. Do subscribe, like and share to stay connected with us. Cheers :)
Very good explanation
Hey Gautham, glad you loved the video. Do subscribe and hit the bell icon to never miss an update from us in the future. Cheers!
Yup I'll check out
please upload a latest advanced map-reduce topic video. thanks a ton in advance.
Hey Ridhi, thanks for checking out our tutorial.
Here's an advanced MapReduce tutorial: ruclips.net/video/QOiV3jG-QTY/видео.html.
Do subscribe to our channel to stay posted on upcoming tutorials. Cheers!
Great explanation and examples
Thank you for appreciating our work. Do subscribe, like and share to stay connected with us. Cheers :)
Thank you so much,,
VeryGood
Thank you for watching our video. Do subscribe, like and share to stay connected with us. Cheers :)
Hi Edureka,
great videos I really enjoy it, I have a question. I followed your example and I created an input file with the data Dear bear etc... and I copied it into dfs and I can actually read it there on the DFS root... When I executed the command with wordcount... everything seems to work fine and the output folder is created but the part-r-0000 file is not created and I have a job failed as task failed failedmaps:1 failedReduce:0
any suggestions?
+M.Z Tabbara, thanks for checking out our tutorial! With regard to the error you're getting, there can be multiple reasons, for instance, some of the deamons are not running. So to get that running, please follow the below given steps:
Open terminal and type
sudo service hadoop-master restart ---->ENTER
Then check the deamons
sudo jps -----ENTER
After the above commands you must get the following deamons running,
[edureka@localhost ~]$ sudo jps;
[sudo] password for edureka:
5840 ResourceManager
5896 NodeManager
5671 NameNode
13071 Jps
5957 JobHistoryServer
5749 DataNode
[edureka@localhost ~]$
After doing the above, try to execute the map reduce code.
There could also be a mistake in the dataset or in the code.
Please check the dataset properly and whether the logic in the MapReduce code is fine but there is any mistake in the dataset or vice versa. For example, there could be an extra line between the rows in the dataset, etc.
Hope this helps. Cheers!
hai sir
please provide the other eco systems like hive ,pig,sqoop like how you provided the mapreduce and hdfs
your explanation is so clear please provide other videos particularly you teached
thanks a lot to edureka
Hey Naga, thanks for checking out our tutorial! We're glad we could help.
You can check out tutorials on Pig, Hive etc here: ruclips.net/p/PL9ooVrP1hQOEmUPq5vhWfLYJH_b9jFBbR.
Do subscribe to our channel to stay posted on upcoming videos. Cheers!
In the slide Application Workflow, there is no arrow from RM to NM. I think there is something wrong in that. As per my understanding, RM asks NM to create a container. And NM is the one who creates the container and launch an Application Master. Please correct me. I am confused.
Hey Vinod, thanks for checking out our tutorial!
Please go through the below given explanation:
The application startup process is the following:
1. a client submits an application to the Resource Manager
2. the Resource Manager allocates a container
3. the Resource Manager contacts the related Node Manager
4. the Node Manager launches the container
5. the Container executes the Application Master
The Application Master is responsible for the execution of a single application. It asks for containers to the Resource Scheduler (Resource Manager) and executes specific programs (e.g., the main of a Java class) on the obtained containers. The Application Master knows the application logic and thus it is framework-specific. The MapReduce framework provides its own implementation of an Application Master.
Hope this helps. Cheers!
Thank you so much for the response.
Point 2 --> Does the Resource Manager allocates a container to the node manager??
Point 4 --> Will the node manager launch the container in the same node manager or a different one?
Hey Vinod, here are the answers to your queries:
1. Does the Resource Manager allocates a container to the node manager?
No, Container is a fraction of the Node Manager capacity and it is used by the client for running a program.
2.Will the node manager launch the container in the same node manager or a different one?
Yes, the node manager launches the container in the same node.
NodeManager - responsible for containers launch, monitoring their resource usage (cpu, memory, disk, network) and reporting it to the ResourceManager/Scheduler.
Hope this helps. Cheers!
great explanation...great..
what are we missing in Hadoop if we just learn by your online videos ...
Hey Ravi, thanks for checking out our tutorial! While these tutorials will give you an introduction and good start to Hadoop, you would be missing out on
1. Interactivity (our live classes are highly interactive) and support from the instructor.
2. Live project component because theoretical training will only help you to a certain extent. (In our course, you'll work on a live project on any of the selected use cases, involving Big Data Analytics using MapReduce, Pig, Hive, Flume and Sqoop)
3. 24X7 support, 365 days of the year, because your training does not end with the classes. Our experts will support you through real-life projects that you might take up after training.
4. Life-time access to learning material and class recordings, not to mention the opportunity to retake classes if there are upgrades to the technology.
If you would like to know more, please share your contact details with us and we will arrange a call with one of our experts. Hope this helps. Cheers!
Thanks ..Will check your site for the course reg...
Thank you so much sir,great explaination
Hey Nirmala, appreciate the compliment. Do subscribe and hit the bell icon to never miss an update from us in the future. Cheers!
Hi Team,I am from Teradata background so wanted to check is Java essential to learn Hadoop while there are other components like PIG,Scoop,Hive to work only on database. what is the scope of java in Hadoop development projects?
Hey Ramana, thanks for checking out our tutorial.
There are no pre-requisites as such to learn Hadoop. Knowledge of core Java and SQL are beneficial to learn Hadoop, but it's not mandatory. Also, we will provide you with a complimentary self-paced course on Java essentials for Hadoop when you enroll for our course to help you brush up on it so you don't need to worry. Please feel free to get in touch with us if you have any questions or concerns. If you'd like us to call and assist you, please share your contact details (we will not make the comment live) and we will get in touch with you to guide you. Alternatively, you can also get in touch with us at 8880862004 if you prefer that.
Hope this helps. Cheers!
Hi
Is resource manager and name node are same.
If not how they are interlinked in a way to process the data.
Hey Jack, sorry for the delay. NameNode is the master node of HDFS, which is the storing part of Hadoop. NameNode stores the metadata of the data stored in HDFS like which block resides in which DataNode, where are the replicas of a block are stored, etc. While ResourceManager is the master node of YARN, which is teh resource management part of Hadoop. It arbitrates all the available cluster resources and thus helps manage the distributed applications running on the YARN system. It works together with the per-node NodeManagers (NMs) and the per-application ApplicationMasters (AMs). Hope this helps!
while executing jar file it says hadoop command not found
Hey Rahul, thanks for checking out our blog. Please use the followig commands:
hadoop jar filename.jar inputpathinHDFS outputpathinHDFS.
Example : hadoop jar Wordcount.jar /input /output
Hope this helps. Cheers!
yes
sir if ther mapper is m and reducer is n then what is the no of combiner
Hey Jeet, thanks for checking out our tutorial.
Here's the complete explanation:
The Combiner class is used in between the Map class and the Reduce class to reduce the volume of data transfer between Map and Reduce. Usually, the output of the map task is large and the data transferred to the reduce task is high.
The following MapReduce task diagram shows the COMBINER PHASE.
How Combiner Works?
Here is a brief summary on how MapReduce Combiner works −
A combiner does not have a predefined interface and it must implement the Reducer interface’s reduce() method.
A combiner operates on each map output key. It must have the same output key-value types as the Reducer class.
A combiner can produce summary information from a large dataset because it replaces the original Map output.
Although, Combiner is optional yet it helps segregating data into multiple groups for Reduce phase, which makes it easier to process.
Also Please go through the below external link for the combiner
www.tutorialspoint.com/map_reduce/map_reduce_combiners.htm
Hope this helps. Cheers!
please give link to download assignment
Hey Sarang, thanks for checking out our tutorial!
The assignment mentioned in this tutorial is part of our Edureka course curriculum and you can access it by enrolling into our course here: www.edureka.co/big-data-and-hadoop.
Please feel free to get in touch with us if you have any questions. Cheers!
how to process large file as I dont know python and dont have the pyhton script?
Hey Rohan, thanks for checking out our tutorial.
Using Hadoop MapReduce one can process large files as it allows you to divide the data into smaller chunks and process them in parallel. You can write MapReduce program using Java, C++, etc. Hope this helps. Cheers!
When I am copying file from local storage to HDFS, it gives an error stating Permission denied
Hi Mudit, configure it using super user privileges it might work like Sudo.
thank you very much sir