question Re: Is it possible to change the default "home" directory (i.e. /user/${USER})? in Archives of Support Questions (Read Only)

Is it possible to change the default "home" directory (i.e. /user/${USER})?

sroberts — Wed, 14 Dec 2016 01:56:39 GMT

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

Former Member — Wed, 14 Dec 2016 02:10:27 GMT

As per the link: https://hadoop.apache.org/docs/r2.6.0/hadoop-project-dist/hadoop-hdfs/hdfs-default.xml

dfs.user.home.dir.prefix   =   /user

The directory to prepend to user name to get the user's home direcotry.

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

Former Member — Wed, 14 Dec 2016 02:29:07 GMT

@Sean Roberts

You can try setting that property "dfs.user.home.dir.prefix" to "hive-site.xml". Is there any specific reason you want to change it?

From command line we can get it's value as

$ hdfs getconf -confKey dfs.user.home.dir.prefix

. I have not tried changing the default "/user" directory of HDFS though.

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

mfoley — Wed, 14 Dec 2016 02:39:06 GMT

@Sean Roberts As noted above, this is controlled by the 'dfs.user.home.dir.prefix' parameter in hdfs-site.xml. However, since this is not a commonly changed parameter, it isn't in the default Ambari configs for HDFS. (It just defaults to the value from hdfs-default.xml.)

To change this value in Ambari, do the following:

In Ambari, select the HDFS service, then select the "Configs" tab.
Within Configs, select the "Advanced" tab
Open the "Advanced hdfs-site" section, and confirm that this parameter isn't already present there.
Open the "Custom hdfs-site" section, and click the "Add property" link
A dialogue pops up, inviting you to type a "key=value" pair in the text field. Enter:
```
dfs.user.home.dir.prefix=/user
```
Press the "Add" button, and the new entry will be converted into a standard parameter entry field.
Now change the value of the field to whatever you want (no blank spaces in the path, please).
Of course after changing configurations, you have to press the "Save" button at the top of the window.

That should do what you need, I hope.

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

mfoley — Wed, 14 Dec 2016 02:48:48 GMT

As usual, parameter changes only affect things going forward. If users have already been created in the default location, their home directories will not be magically re-created in the new location. This could cause problems, depending on whether processes use the parameter vs using hardwired "/user" prefix. For your site-defined users, you can just move their home directories with dfs commands. For the pre-defined Stack service users, you'll need to experiment to see whether they want their home directories to stay in /user or be moved to value(dfs.user.home.dir.prefix). I would start by leaving them in place, but that's just a guess.

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

mfoley — Thu, 15 Dec 2016 02:19:46 GMT

One way to see whether any Stack services use hardwired "/user" prefix would be to use Ambari to install the whole Stack on a lab machine. Make a change to "dfs.user.home.dir.prefix", to something other than "/user", during Install Wizard time, BEFORE letting Ambari do the actual installation, thus making sure everything from the beginning sees the non-default value. Let it install, start all the services and let them run a few minutes, then see if anything got created under /user/* in HDFS. Sorry I don't have time to do the experiment right now, but if you do please report the results back here as a comment for others to learn from. If you find services that apparently hardwire the "/user" prefix, I'll enter bugs against those components and try to get them fixed.

Re: Is it possible to change the default "home" directory (i.e. /user/${USER})?

sroberts — Wed, 21 Dec 2016 17:39:52 GMT

@Matt Foley - Does HDFS have home references such as ~ or ${HOME} ?