Is there a way to batch upload files to Hadoop under a Hortonworks VM running CentOS? I see I can use the Ambari - Sandbox's HDFS Files tool, but that only allows uploading one-by-one. Apparently you could use Redgate's HDFS Explorer in the past, but it's no longer available. Hadoop is made to process big data, but it's absurd having to upload all files one-by-one...
Thank you!
Of course you can use the * wildcard in copyFromLocal, f.e.:
hdfs dfs -copyFromLocal input/* /tmp/input
Related
I was learning hadoop and till now I configured 3 Node cluster
127.0.0.1 localhost
10.0.1.1 hadoop-namenode
10.0.1.2 hadoop-datanode-2
10.0.1.3 hadoop-datanode-3
My hadoop Namenode directory looks like below
hadoop
bin
data-> ./namenode ./datanode
etc
logs
sbin
--
--
As I learned that when we upload a large file in the cluster in divide the file into blocks, I want to upload a 1Gig file in my cluster and want to see how it is being stored in datanode.
Can anyone help me with the commands to upload file and see where these blocks are being stored.
First, you need to check if you have Hadoop tools in your path, if not - I recommend integrate them into it.
One of the possible ways of uploading a file to HDFS:hadoop fs -put /path/to/localfile /path/in/hdfs
I would suggest you read the documentation and get familiar with high-level commands first as it will save you time
Hadoop Documentation
Start with "dfs" command, as this one of the most often used commands
I have installed both hadoop and spark locally on a windows machine.
I can access HDFS files in hadoop, e.g.,
hdfs dfs -tail hdfs:/out/part-r-00000
works as expected. However, if I try to access the same file from the spark shell, e.g.,
val f = sc.textFile("hdfs:/out/part-r-00000")
I get an error that the file does not exist. Spark can access files in the windows file system using the file:/... syntax, though.
I have set the HADOOP_HOME environment variable to c:\hadoop which is the folder containing the hadoop install (in particular winutils.exe, which seems to be necessary for spark, is in c:\hadoop\bin).
Because it seems that HDFS data is stored in the c:\tmp folder, I was wondering whether there is would be a way to let spark know about this location.
Any help would be greatly appreciated. Thank you.
If you are getting file doesn't exist, that means your spark application(code snippet) is able to connect to HDFS.
The HDFS file path that you are using seems wrong.
This should solve your issue
val f = sc.textFile("hdfs://localhost:8020/out/part-r-00000")
I'm working with Windows and trying to set up Spark.
Previously I installed Hadoop in addition to Spark, edited the config files, run the hadoop namenode -format and away we went.
I'm now trying to achieve the same by using the bundled version of Spark that is pre built with hadoop - spark-1.6.1-bin-hadoop2.6.tgz
So far it's been a much cleaner, simpler process however I no longer have access to the command that creates the hdfs, the config files for the hdfs are no longer present and I've no 'hadoop' in any of the bin folders.
There wasn't an Hadoop folder in the spark install, I created one for the purpose of winutils.exe.
It feels like I've missed something. Do the pre-built versions of spark not include hadoop? Is this functionality missing from this variant or is there something else that I'm overlooking?
Thanks for any help.
By saying that Spark is built with Hadoop, it is meant that Spark is built with the dependencies of Hadoop, i.e. with the clients for accessing Hadoop (or HDFS, to be more precise).
Thus, if you use a version of Spark which is built for Hadoop 2.6 you will be able to access HDFS filesystem of a cluster with the version 2.6 of Hadoop via Spark.
It doesn't mean that Hadoop is part of the pakage and downloading it Hadoop is installed as well. You have to install Hadoop separately.
If you download a Spark release without Hadoop support, you'll need to include the Hadoop client libraries in all the applications you write wiìhich are supposed to access HDFS (by a textFile for instance).
I am also using same spark in my windows 10. What I have done create C:\winutils\bin directory and put winutils.exe there. Than create HADOOP_HOME=C:\winutils variable. If you have set all
env variables and PATH like SPARK_HOME,HADOOP_HOME etc than it should work.
I was going through the HADOOP fs commands list. I am little perplexed not to find any "cd" command in hadoop fs.
Why is it so? It might sound silly question for the HADOOP users, but as I am beginner I can not understand why there is no list of cd command in HADOOP fs level?
Think about it like this:
Hadoop has a special file system called "hdfs" which runs on top of existing say linux file system. There is no concept of current or present working directory a.k.a. pwd
Let's say we have following structure in hdfs:
d1/
d2/
f1
d3/
f2
d4/
f3
You could do cd in your Linux file system from moving from one to the other but do you think changing directory in hadoop would makes sense? HDFS is like virtual file system and you dont directly interact with hdfs except via hadoop command or job tracker.
HDFS provides various features that enable accessing HDFS(Hadoop Filesystem) easy on local machines or edge nodes. You have an option to mount HDFS using any of the following methods. Once Hadoop file system is mounted on your machine, you may use cd command to browse through the file system (It's is like mounting remote network filesystem like NAS)
Fuse dfs (Available from Hadoop 0.20 onwards )
NFSv3 Gateway access to HDFS data (Available from Hadoop version
Hadoop 2.2.0)
How do I copy a directory in HDFS to another directory in HDFS?
I found the copyFromLocalFile functions that copy from the local FS to HDFS, but I want both of the source/destination to be in HDFS.
Thanks
Use distcp command.
The canonical use case for distcp is for transferring data between two HDFS clusters.
If the clusters are running identical versions of Hadoop, the hdfs scheme is
appropriate:
% hadoop distcp hdfs://namenode1/foo hdfs://namenode2/bar
If you want to do it through Java code, see class org.apache.hadoop.tools.DistCp and call it appropriately.
You can try FileUtil.copy
http://hadoop.apache.org/common/docs/current/api/org/apache/hadoop/fs/FileUtil.html