Hi Ravi.

I have set dfs.permissions as true. But that problem still exist. Today I
formatted the HDFS and restart Hadoop, and it is now working. It may be
caused by inconsistent state of HDFS.

Thank you very much for your help!

Best regards,
Starry

/* Tomorrow is another day. So is today. */


On Fri, Dec 18, 2009 at 04:51, Ravi Phulari <[email protected]> wrote:

>  Suggestion.
>
> Hadoop uses unix “whoami” utility to check users and enforce permissions.
> Make sure your whoami is reporting correct user name (when you are changing
> from user1 to user2 ).
>
> Also make sure in configuration file hdfs-site.xml dfs.permission.enabled
> is true. (by default it’s set to true )
>
> <property>
>   <name>dfs.permissions.enabled</name>
>   <value>true</value>
>   <description>
>     If "true", enable permission checking in HDFS.
>     If "false", permission checking is turned off,
>     but all other behavior is unchanged.
>     Switching from one parameter value to the other does not change the
> mode,
>     owner or group of files or directories.
>   </description>
> </property>
>
> Hope this helps.
>
> -Ravi
>
>
> On 12/17/09 4:22 AM, "Starry SHI" <[email protected]> wrote:
>
> Hi.
>
> I wonder how permission control can be used in HDFS?
>
> I am using hadoop 0.20.1, and I have 3 user accessing to HDFS. I use
> user1's
> account to create a file and chmod 600 to this file in HDFS. However, I
> tried to use user2 and user3's account to access the file belonging to
> user1, they can still read  the contents of the file!!! This means the
> permission control is no use in HDFS.
>
> What I tried to do is to avoid user2 and user3 to read the file from user1
> stored in HDFS. In the configuration I have already set dfs.permissions as
> "true". Can somebody tell me how to enable permission control in HDFS?
>
> Best regards,
> Starry
>
> /* Tomorrow is another day. So is today. */
>
>
> Ravi
> --
>
>

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