Member since
04-03-2019
89
Posts
5
Kudos Received
5
Solutions
My Accepted Solutions
Title | Views | Posted |
---|---|---|
3394 | 01-21-2022 04:31 PM | |
5833 | 02-25-2020 10:02 AM | |
3492 | 02-19-2020 01:29 PM | |
2546 | 09-17-2019 06:33 AM | |
5563 | 08-26-2019 01:35 PM |
11-04-2020
10:59 PM
I resolved the error by following advice from this post. https://community.cloudera.com/t5/Support-Questions/Sharing-how-to-solve-HUE-and-HBase-connect-problem-on-CDH-6/td-p/82030
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11-04-2020
03:10 PM
I got the same error with HappyBase. My code has been working fine for a few weeks. Somehow Thrift API stopped. I restarted the API and then I got this error.
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07-30-2020
03:38 PM
The unpack command will not work without that extra dash. https://stackoverflow.com/questions/34573279/how-to-unzip-gz-files-in-a-new-directory-in-hadoop/43704452 I had another try with a file name as the destination. hdfs dfs -cat /user/testuser/stage1.tar.gz | gzip -d | hdfs dfs -put - /user/testuser/test3/stage1 the file stage1 appeared in the test3 directory. There is something interesting. The stage1.tar.gz contains three empty txt files. "hdfs dfs -cat /user/testuser/test3/-" ouptut nothing and the file size is 0.1k "hdfs dfs -cat /user/testuser/test3/stage1" output some texts including original file names inside. Also the file size is 10k.
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07-30-2020
03:01 PM
@Shelton Thanks for the quick response. Here is my code to create the gz file. tar cvzf ~/stage1.tar.gz ./* I tried the following command to upload and unzip it into a hdfs directory /user/testuser/test3 hdfs dfs -copyFromLocal stage1.tar.gz /user/testuser
hdfs dfs -cat /user/testuser/stage1.tar.gz | gzip -d | hdfs dfs -put - /user/testuser/test3 However, what I got in /user/testuser/test3 is a file with the name "-", not the multiple files in the stage1.tar.gz. Does your solution mean to concatenate all files together? Please advise. Thanks.
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07-30-2020
11:31 AM
I am copying a large number of small files (hl7 message files) from Linux local storage to hdfs. I wonder whether this is a performance difference between copying files one by one (though a script) or just using one statement like "hadoop fs -put ./* /hadoop_path". Additional background info: some files have space in their file name, if I use the command "hadoop fs -put ./* /hadoop_path", I got the error "put: unexpected URISyntaxException" for those files. If there is no performance difference, I would just copy file one at a time and my script replaces the space with "%20". Otherwise, I have to rename all files, replacing spaces with underscores, and then use batch copy.
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HDFS
02-25-2020
10:02 AM
I got the following responses from Cloudera Certification. Regarding Question #1, the FAQ page has the most the up-to-date information. So right now I'd better hold off purchasing the exam until the DE575 is relaunched. Regarding Question #2, the course is the "Spark and Hadoop Developer" training course is the one I should take for preparing DE575. Regarding Question #3, the environment for the exam is fixed and only available on CDH. Candidates do not have the option to take the exam in an HDP environment. The skills tested are applicable to HDP development as well, it is in the developer track, so it should have nothing to do with the environment that it is running in. It is primarily interested in transforming data that sits on the cluster.
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02-19-2020
01:29 PM
1 Kudo
Finally, I figured out what is going on. The root cause is that, I only set up testuser on edge nodes, not the name node. I looked into this page, https://hadoop.apache.org/docs/r3.1.1/hadoop-project-dist/hadoop-common/GroupsMapping.html, which shows that "For HDFS, the mapping of users to groups is performed on the NameNode. Thus, the host system configuration of the NameNode determines the group mappings for the users." After I created the user on the NameNode and ran the command hdfs dfsadmin -refreshUserToGroupsMappings the copy is successful and there is no permission-denied error.
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02-10-2020
11:51 AM
@GangWar Here it is. $ id -Gn testuser hadoop wheel hdfs
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02-10-2020
09:05 AM
I have run the following test case several times and got the same result. Context: 1. My HDP cluster uses the simple mode to determine user identity. Kerberos is not enabled. 2. Below is the permission on hdfs folder /data/test
drwxrwxr-x - hdfs hadoop 0 2020-02-07 13:33 /data/test
So hdfs (the super user) is the owner and hadoop is the owner group. Both the owner user and owner group has write permission on the /data/test folder.
Steps:
On an edge node, I used ID command to confirm that the logged on user "testuser" is in hadoop group.
$ id
uid=1018(testuser) gid=1003(hadoop) groups=1003(hadoop),10(wheel), 1002(hdfs) context=unconfined_u:unconfined_r:unconfined_t:s0-s0:c0.c1023
However, testuser still ran into "Permission Denied".
$ hadoop fs -put ./emptyfile1.txt /data/test
put: Permission denied: user=testuser, access=WRITE, inode="/data/test":hdfs:hadoop:drwxrwxr-x
Then I used hdfs account to changed the folder owner to be testuser.
$ hadoop fs -chown testuser /data/test
From the same edge node, now testuser ran put command successfully.
Here is my question: why testuser cannot write to the hdfs folder via the owner group permissions?
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HDFS
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Hortonworks Data Platform (HDP)
01-31-2020
09:07 AM
@cjervis Thanks. I reviewed the FAQ page, but it does not answer my questions. I guess I'd better wait until tomorrow, because the page mentioned the date February 1, 2020 several times for new launches or other changes.
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