Unable to over write file with cp command through NFS Gateway into HDFS.

[#1]

I am trying to over write the file with cp command and it failed with below error.

cp: cannot create regular file "filename" : Invalid argument

i checked the error log and got the below error.

ERROR nfs3.RpcProgramNfs3 (RpcProgramNfs3.java:setattr(436)) - Setting file size is not supported when setattr, fileId: 18463

Can some one Help me with it.

Thanks in Advance.

[#2]

Hi, cp is working with the option "-f". But when i try with python it is failing with below error.

IOError: [Errno 22] invalid mode ('wb+') or filename: '/file_path/testWrite.txt'

Can some one help with it.

Thanks.

[#3]

Hi Paramesh,what is the python code you are using.

[#4]

Hi Selavan,

First of all thanks for your reply. I used below code with the python write mode of w,w+ and wb+.

open_file = open("/hdfs_nfs/hdfs_Data/sampledata/testWrite.txt", 'wb+')
open_file.write("This is just a sample data")
open_file.close()

The file "testWrite.txt" is getting created in given path (HDFS Mount point) when I run this for first time.

I am getting below error, when I execute above code from second time onwards.

IOError: [Errno 22] invalid mode ('wb+') or filename: '/hdfs_nfs/hdfs_Data/sampledata/testWrite.txt'

Thanks.

[#5]

@Paramesh malla, Is testWrite.txt file present on HDFS while running test code second time ? If yes, please delete /hdfs_nfs/hdfs_data/sampledata/testWrite.txt and rerun.

HDFS only supports append, so if you intend to append data after file creation, use 'a' option.

with open(filename,'a')as f:
    f.write(text)

[#6]

@Paramesh malla

You need to overwrite file with python(like cp -f) in order to get it working.

Please refer below link:

https://stackoverflow.com/questions/2424000/read-and-overwrite-a-file-in-python

Hope this helps.

[#7]

Hi Kuldeep,

Thanks for the reply. I tried the method that was mentioned on above given link. still it is not working.

I am getting below error.

Traceback (most recent call last):
  File "write_test.py", line 7, in <module>
    open_file.truncate()
IOError: [Errno 22] Invalid argument.