This information can be found in http://hadoop.apache.org/core/docs/current/hdfs_permissions_guide.html Nicholas
----- Original Message ---- > From: Chris Collins <[EMAIL PROTECTED]> > To: [email protected] > Sent: Wednesday, June 11, 2008 9:31:18 PM > Subject: Re: client connect as different username? > > Thanks Doug, should this be added to the permissions doc or to the > faq? See you in Sonoma. > > C > On Jun 11, 2008, at 9:15 PM, Doug Cutting wrote: > > > Chris Collins wrote: > >> You are referring to creating a directory in hdfs? Because if I am > >> user chris and the hdfs only has user foo, then I cant create a > >> directory because I dont have perms, infact I cant even connect. > > > > Today, users and groups are declared by the client. The namenode > > only records and checks against user and group names provided by the > > client. So if someone named "foo" writes a file, then that file is > > owned by someone named "foo" and anyone named "foo" is the owner of > > that file. No "foo" account need exist on the namenode. > > > > The one (important) exception is the "superuser". Whatever user > > name starts the namenode is the superuser for that filesystem. And > > if "/" is not world writable, a new filesystem will not contain a > > home directory (or anywhere else) writable by other users. So, in a > > multiuser Hadoop installation, the superuser needs to create home > > directories and project directories for other users and set their > > protections accordingly before other users can do anything. Perhaps > > this is what you've run into? > > > > Doug
