Download file weekly from FTP to HDFS
Since you're using CDH5, it's worth noting that the NFSv3 interface to HDFS is included in that Hadoop distribution. You should check for "Configuring an NFSv3 Gateway" in the CDH5 Installation Guide documentation.
Once that's done, you could use wget, curl, python, etc. to put the file onto the NFS mount. You probably want to do this through Oozie ... go into the job Designer and create a copy of the "Shell" command. Put in the command that you've selected to do the data transfer (python script, curl, ftp, etc), and parameterize the job using ${myVar}.
It's not perfect, but I think it's fairly elegant.
I suppose you want to pull a file.
One simple solution is that you can use coordinator which runs a workflow.
Workflow should have shell action
http://oozie.apache.org/docs/3.3.0/DG_ShellActionExtension.html
The script in that can just have
wget http://myftp.com/file.name
You can do all what you want in script