hdp_ambari.md

Lets assume that you have a cluster with the name - awesome_cluster.

How to enable a HDFS View

On a fresh Ambari cluster, we need to follow following steps to create the HDFS view.

Allow the superuser to impersonate other users.

Well... Ambari tries to impersonate the current logged in user with the superuser, and thus the simplest ( but not the best ) thing is to allow the superuser to imperonate all users. Similarily we also need to tell Ambari the name of the host from which the superuser can connect ( simplest is to allow all hosts ).

On Ambari dashboard go to Services > HDFS > Config > Advanced > Custom Core Site and add following new paramters

hadoop.proxyuser.root.groups = *
hadoop.proxyuser.root.hosts = *

Make user's home directory on HDFS

Now you will have to create a corresponding user ( in this case 'admin' ) on your hdfs,

sudo su hdfs
hadoop fs -mkdir /user/admin
hadoop fs -chown admin:hadoop /user/admin

Similarly... create dfs home directory for any other users ( awesome.user )

sudo su hdfs
hadoop fs -mkdir /user/awesome.user
hadoop fs -chown awesome.user:hadoop /user/aswesome.user

Create the HDFS View

GO to admin > manage ambari > Views > HDFS > Create Instance.

We will need to change following fields,

Field name	Value
Instance Name	awesome_hdfs_view
Display Name	AWESOME_HDFS_VIEW
Description	My awesome view for awseome hdfs

Its fine to create with other things as default.

Grant permissions

The admin user will have permission for this view by default, as for other users ( awsome.user ) follow these steps.

• Go to admin > manage ambari > User + Group Management > Groups and create a group named hdfs_users.
• Now go to admin > manage ambari > Views > HDFS > AWESOME_HDFS_VIEW > Permissions and grant access to group hdfs_users.
• Now go to admin > manage ambari > User + Group Management > Groups > hdfs_users and add awesome.user to local users of this group.

How to enable a Hive View

Allow the Hive superuser to impersonate other users.

Ambari tries to impersonate the current logged in user with the hive superuser, and thus the simplest ( but not the best ) thing is to allow the hive superuser to imperonate all users. Similarily we also need to tell Ambari the name of the host from which the hive superuser can connect ( simplest is to allow all hosts ).

On Ambari dashboard go to Services > HDFS > Config > Advanced > Custom Core Site and add following new paramters

hadoop.proxyuser.hive.groups = *
hadoop.proxyuser.hive.hosts = *

Create the Hive View

GO to admin > manage ambari > Views > Hive > Create Instance.

We will need to change following fields,

Field name	Value
Instance Name	awesome_hive_view
Display Name	AWESOME_HIVE_VIEW
Description	My awesome view for awseome hive

Its fine to create with other things as default.

Grant permissions

The admin user will have permission for this view by default, as for other users ( awsome.user ) follow these steps.

• Go to admin > manage ambari > User + Group Management > Groups and create a group named hive_users.
• Now go to admin > manage ambari > Views > HDFS > AWESOME_HIVE_VIEW > Permissions and grant access to group hive_users.
• Now go to admin > manage ambari > User + Group Management > Groups > hive_users and add awesome.user to local users of this group.

Still not done - RA040 I/O error while requesting Ambari

Logically... your Hive view should have been usable now... but actually it is not. Your admin user will work but somehow other users will not be able to use the hive view.

• The simplest way to solve this problem is to grant the respective user read-only permission to Ambari dashboard and then login to Ambari dashboard at least once. ( admin > manage ambari > clusters > awseom_cluster > Permissions > Read-Only ) You can remove this Ambari dashboard permission later.
• Other way is to login to hive-shell using the respective user.