I'm learning data analysis in Zeppelin, I'm a mechanical engineer so this is outside my expertise.
I am trying to download two csv files using a file that contains the urls, test2.txt. When I run it I get no output, but no error message either. I've included a link to a screenshot showing my code and the results.
When I go into Ambari Sandbox I cannot find any files created. I'm assuming the directory the file is in is where the csv files will be downloaded too. I've tried using -P as well with no luck. I've checked in man wget but it did not help.
So I have several questions:
How do I show the output from running wget?
Where is the default directory that wget stores files?
Do I need additional data in the file other than just the URLs?
Screenshot: Code and Output for %sh
Thanks for any and all help.
%sh
wget -i /tmp/test2.txt
%sh
# list the current working directory
pwd # output: home/zeppelin
# make a new folder, created in "tmp" because it is temporary
mkdir -p /home/zeppelin/tmp/Folder_Name
# change directory to new folder
cd /home/zeppelin/tmp/Folder_Name
# transfer the file from the sandbox to the current working directory
hadoop fs -get /tmp/test2.txt /home/zeppelin/tmp/Folder_Name/
# download the URL
wget -i test2.txt
I am bit new to hadoop. I have recently install a stable version of Apache Hadoop 2.7.2 on ubuntu 14.04 OS.
I am trying to execute some basic Hadoop command such as follow
hadoop version
The command gives me the correct output as follows that is correct.
However, when I try to execute the hadoop fs -ls, it give me error.
I have searched the previous question related to this problem on stackoverflow such as StackoverflowQuestion. But, I am not finding /user directory in my hadoop installation. Could you please help me how can I resolve this issue?
The content of my .bashrc file is as follows:
The content of hdfs-site.xml file is as follows:
First of all the command "hadoop fs -ls" is a command to the HDFS file system and not a Linux command.
Second, the command as you typed it is incomplete. The correct syntax is "hadoop fs -ls [-d] [-h] [-R] " where the [-d], [-h] and [-R] components of the command are optional. That said, you MUST specify a path for the "args" component. The "args" component of the command expects an HDFS path (e.g. substituting / for "args" will list the entire tree ** ON HDFS ** starting at the HDFS root directory /). You will need to create a directory called "user" on HDFS under the root directory using "hadoop fs -mkdir /user". The the command "hadoop fs -ls /user" will work and will show an empty user directory.
Third, there is no way to tell HDFS to use a value for the "args" by supplying it a value of a local filesystem (Linux) path ...which is what you are attempting or understanding it to be. Any value for "args" must resolve to an HDFS filesystem path and not a Linux filesystem path.
Fourth, for newcomers to Hadoop, it is very important to have a clear distinction between the native host operating system filesystem (in this case Linux filesystem) and the Hadoop filesystem (in this case HDFS).
one thing to note when doing a hadoop commands in v2.7.2 is that, hadoop works on top of Linux OS, hence when we want to access into Hadoop Distributed File System, we would use something like this command; hdfs dfs -ls / instead of hadoop fs -ls.
Also, in your hdfs-site.xml configurations, you seemed to miss out adding this properties.
<property>
<name>dfs.datanode.dir</name>
<value>file://path/to/datanode</value>
</property>
Please take note of your $HADOOP_HOME as well.
I'm trying to load a .csv file into HDFS. For that I do this:
hdfs dfsadmin -safemode leave
sudo -u hdfs hadoop fs -copyFromLocal /home/cloudera/reduced.csv /user/cloudera
But when I submit this I'm getting:
copyFromLocal: Cannot create file/user/cloudera/reduced.csv._COPYING_. Name node is in safe mode.
I already see this post:
Name node is in safe mode. Not able to leave
But I'm still get this error...
In a Windows environment, I'm trying to load a .csv file with statement:
LOAD CSV WITH HEADERS FROM "file:///E:/Neo4j/customers.csv" AS row
It seems not to work properly and returns:
Couldn't load the external resource at:
file:/E:/Neo4j/Customers.csv
Neo.TransientError.Statement.ExternalResourceFailure
What am I doing wrong? thanks in advance
I was getting this error on Community Edition 3.0.1 on Mac OS X 10.10
It appears that the LOAD CSV file:/// looks for files in a predefined directory. One would think that in the argument that one would give the Cypher statement the full path but that is not the case.
The file:/// - for my situation" meant that neo4j would append the given argument you gave to one that was already predefined and then go look for that combined path
The file:/// pre-defined directory directory did not exist entirely
/Users/User/Documents/Neo4j/default.graphdb/import, in my computers directory structure I was missing the "/import" folder, which was not created at install
To fix on my system, I created an "import" directory, put the file to be read in that directory. I executed the Cypher load statement I ONLY put the name of the file to be read in the file argument i.e.
LOAD CSV file:///data.csv
this worked for me.
It appears to be a security configuration. Here's the original answer I found: https://stackoverflow.com/a/37444571/327004
You can add the following setting in conf/neo4j.conf in order to bypass this :
dbms.security.allow_csv_import_from_file_urls=true
Or change the import directory dbms.directories.import=import
You can find the answer in the file
"C:\Users\Jack\AppData\Roaming\Neo4j Community Edition\neo4j.conf"
(above "dbms.directories.import=import")
For version neo4j-community_windows-x64_3_1_1 you have to comment out this line or you have to create the folder \import (which isn´t created through the installation) and add your file into the folder.
There it´s written that due to security reasons they only allow file load from the \Documents\Neo4j\default.graphdb\import folder
After commenting out on # dbms.directories.import=import , you can execute e.g. from
LOAD CSV FROM "file:///C:/Users/Jack/Documents/products.csv" AS row
In neo4j.conf I didn´t have to add/set
dbms.security.allow_csv_import_from_file_urls=true
On (Arch) Linux + neo4j-community-3.4.0-alpha09, edit $NEO4J_HOME/conf
/neo4j.conf:
uncomment or add: dbms.security.allow_csv_import_from_file_urls=true
comment: #dbms.directories.import=import
Restart neo4j (in terminal: neo4j restart), and reload the Neo4j Browser (http://localhost:7474/browser/) if you are using a web browser as your Neo4j interface/GUI.
Then, you should be able to load a csv from outside your $NEO4J_HOME/... directory
E.g.,
LOAD CSV WITH HEADERS FROM "file:///mnt/Vancouver/Programming/data/metabolism/practice/a.csv" AS ...
where my $NEO4J_HOME/ is /mnt/Vancouver/apps/neo4j/neo4j-community-3.4.0-alpha09/
LOAD CSV WITH HEADERS FROM "file:/mnt/Vancouver/Programming/data/metabolism/practice/a.csv" AS ...
also works, but not
LOAD CSV WITH HEADERS FROM "file://mnt/Vancouver/Programming/data/metabolism/practice/a.csv" AS...
or
LOAD CSV WITH HEADERS FROM "/mnt/Vancouver/Programming/data/metabolism/practice/a.csv" AS...
i.e. use ...file:/... or ...file:///...
It's probably an URL issue, try file:c:/path/to/data.csv
See my blog posts:
http://jexp.de/blog/2014/10/load-cvs-with-success/
http://jexp.de/blog/2014/06/load-csv-into-neo4j-quickly-and-successfully/
For the ubuntu system, I placed the file in /usr/lib/neo4j which helped me solved the issue. On every other location, i tried giving full permissions(777) but the problem remains the same. After going through another stackoverflow post, i realized that the file should be kept in neo4j directory.
In the Neo4j desktop select the database you are using, go to the setting and there you will find the solution... just comment the "dbms.directories.import=import" line
# This setting constrains all LOAD CSV import files to be under the import directory. Remove or comment it out to
# allow files to be loaded from anywhere in the filesystem; this introduces possible security problems. See the
# LOAD CSV section of the manual for details.
dbms.directories.import=import ### COMMENT THIS LINE
For macOS Mojave v 10.14.5
Actually, I had to uncomment dbms.directories.import=import from ~/Library/Application Support/Neo4j Desktop/Application/neo4jDatabases/database-e2dd2a9c-d450-4639-861b-1e7e42b56b31/installation-3.5.5/conf/neo4j.conf and restart the service. Then it worked. All files has to be placed in import directory.
Run command LOAD CSV WITH HEADERS FROM 'FILE:/<yourCSV>.csv' as l return l
I am using the Neo4j Desktop and as others have said, the default graph database has a predefined import location. You can find the location by using the UI. If you put the CSV into the import directory, then you can use the relative path directly from you load csv command
Neo4j version is 3.1.1, OS is win10.
For me, LOAD CSV would read from Neo4j_Database_Location/testDB/import/artists.csv.
At first, I put csv file on the path F:\code\java\helloworld\artists.csv, and my cypher sentence is
LOAD CSV FROM 'file:///F:\\code\\java\\helloworld\\artists.csv' AS line
CREATE(:Artist {name:line[1],year:toInt(line[2])})
Then I get the error message returned as follows:
Couldn't load the external resource at: file:/D:/Neo4j/db/testDB/import/code/java/helloworld/artists.csv
It means neo4j itself concat the file path.
"D:/Neo4j/db/testDB/import/" is the Neo4j database location, and the "code/java/helloworld/artists.csv" is the csv file location.
For example, I install Neo4j on the path D:\Neo4j\Neo4j CE 3.1.1, and database loaction is D:\Neo4j\db. I put the CSV file on the path D:\Neo4j\db\testDB\import\artist.csv. If you don't have the file folder "import" on the path, you should creat it by yourself and put your file in the folder "import".
Then, put your csv file in the path, and input cyper sentence:
LOAD CSV from 'file:///artist.csv' as LINE
CREATE(:Artist {name:line[1],year:toInt(line[2])})
In a word, once you put the CSV file in the right path, the problem can be solved.
Related explaination in the LOAD CSV developer-manal
If dbms.directories.import is set to the default value import, using the above URLs in LOAD CSV would read from /import/myfile.csv and import/myproject/myfile.csv respectively.
If it is set to /data/csv, using the above URLs in LOAD CSV would read from /data/csv/myfile.csv and /data/csv/myproject/myfile.csv respectively.
Set the Property "dbms.directories.import=import"
Create folder 'import' explicitly at "/Users/User/Documents/Neo4j/default.graphdb/" because pre-defined directory did not exist entirely
place the csv data set here in the import folder
then run the code like - LOAD CSV FROM "file:///C:/customers.csv" AS row
In addition after you run the line, you can analyze what is going wrong in the code section to get a better understanding
you put your dataset into the import directory in neo4j-community path.
Then re-run your command.
Add your csv file in the import folder of neo4j installation guide to do this.
open neo4j and start graph of ur project
then in open folders tab open import folders
Copy ur csv file in this folder
Copy that part in ur load syntax as file:///C:/neo4j_module_datasets/test.csv since ur neo4j in running
in C drive
Snapshot for your reference
Use the following syntax:
LOAD CSV WITH HEADERS FROM "file:///my_collection.csv" AS row CREATE (n:myCollection) SET n = row
If you are running a docker then, follow these commands before running above query:
docker run \
-p=7474:7474 \
-p=7687:7687 \
-v=$HOME/neo4j/data:/data \
-v=$HOME/neo4j/logs:/logs \
-v=$HOME/local_import_dir:/var/lib/neo4j/import \
neo4j:3.0
Then,
sudo cp my_collection.csv /home/bajju/local_import_dir/
One of the following should solve the LOAD CSV errors (assuming you have dbms.security.allow_csv_import_from_file_urls=true)
If using Linux check for the permissions for the file. Change it using chmod 777 file_name.csv
Check if the file format/format for the contents within the file is correct.
The easiest way (be ware of security) is to serve you directory over http and use the http import
in the command line go the folder where csv files are lcoated
run the following depending on your python env.
Python 2
$ python -m SimpleHTTPServer 8000
Python 3
$ python3 -m http.server 8000
- Now you can load your files from your local host
LOAD CSV FROM 'http://localhost:8000/mycsvfile.csv' AS row
return row
- you can actually expose files on one host and load them where your DB is running by exposing the folder and replacing localhost with your IP
I recently installed hadoop on my local ubuntu. I have started data-node by invoking bin/start-all.sh script. However when I try to run the word count program
bin/hadoop jar hadoop-examples-1.2.1.jar wordcount /home/USER/Desktop/books /home/USER/Desktop/books-output
I always get a connect exception. The folder 'books' is on my deskop(local filesystem). Any suggestions on how to overcome this?
I have followed every steps in this tutorial. I am not sure how to get rid of that error. All help will be appreciated.
copy your books file into your hdfs
and for the input path argument use hdfs path of your copied book file.
for more detail go through below link.
http://cs.smith.edu/dftwiki/index.php/Hadoop_Tutorial_1_--_Running_WordCount#Basic_Hadoop_Admin_Commands
There is a bit of confusion here, when you run the hadoop ... command then the default filesystem which it uses is the hadoop distributed filesystem hence the files must be located on the hdfs for hadoop to access it.
To copy files from the local filesystem to the hadoop filesystem you have to use the following command
hdfs dfs -copyFromLocal /path/in/local/file/system /destination/on/hdfs
One more thing if you want to run the program from your IDE directly then sometimes you get this issue which can be solved by adding the
core-site.xml and hdfs-site.xml files in the conf variable something like
conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/core-site.xml"));
conf.addResource(new Path("/usr/local/hadoop/etc/hadoop/hdfs-site.xml"));
change the path above to the hdfs-site.xml and core-site.xml to your local path.
So the above arguments can also be provided from the command line by adding them to the classPath with -cp tag.