Different 'user' accounts for ambari and hive ?

[#1]

Hi team

I installed a 3 node hadoop cluster on AWS using ambari and the user I used in the ambari set up wizard was "ec2-user". So in my understanding, ambari and the hadoop clusters would have been installed using ec2-user.

Then, I log into the node where HIVE / metastore is installed and try to run "hive" form command line, then i got this error message:

Permission denied: user=ec2-user, access=WRITE, inode="/user/ec2-user":hdfs:hdfs:drwxr-xr-x

Then, i executed "sudo hive" and I got this,

Permission denied: user=root, access=WRITE, inode="/user/root":hdfs:hdfs:drwxr-xr-x

Out of curiosity, I then did sudo -iu hdfs and then launched hive, and surprisingly it worked and I got the hive> prompt.

I am confused where or how this user hdfs was created? what is the best practice in terms of user accounts? May be I shouldnt have installed the setup using ec2-user? Please can somebody shed some light?

please also see some note on my other question, related to what issues i faced when running ambari - https://community.hortonworks.com/questions/102111/error-when-creating-instances-using-ambari.html#a...

Regards

Naveen Keshava

[#2]

Each service has its own default service account that ambari will create and these service can belong to hadoop group. You can customize these if needed.

https://docs.hortonworks.com/HDPDocuments/Ambari-2.5.0.3/bk_ambari-administration/content/defining_s...

Is ec2-user the user account that ambari service runs as? Maybe that is what you did?

[#3]

Your have wrong ownership that HDFS user's home directory.

The ownership of HDFS user home directory should be like this.

/user/ec2-user >> ec2-user:ec2-user or ec2-user:hadoop

/user/root >> root:root or root:hadoop

Try these below commands.

# su hdfs

# hdfs dfs -chown -R ec2-user:ec2-user /user/ec2-user

# hdfs dfs -chown -R root:root /user/root

[#4]

Please run the below command

sudo su hdfs

hadoop fs -mkdir -p /user/ec2-user

hdfs dfs -chown -R ec2-user:ec2-user /user/ec2-user

getout from the HDFS login

[ec2-user@ip-172-**-*-** ~]$ hive

log4j:WARN No such property [maxFileSize] in org.apache.log4j.DailyRollingFileAppender.

Logging initialized using configuration in file:/etc/hive/2.6.5.0-292/0/hive-log4j.properties

hive>