Authentication via Active Directory and LDAP

Overview

The LDAP and Active Directory authenticators available in Datameer provide remote authentication services for Datameer users. Administrators can configure Datameer to use their existing LDAP or Active Directory systems as the authenticator of record allowing for centralized management of user accounts and credentials outside of Datameer. Users can authenticate with Datameer using existing credentials which are verified against the remote system on every login. If the remote system no longer sanctions the user, access to Datameer is denied. This simplifies Datameer administration and allows end-users to use familiar single sign-on credentials when accessing Datameer.

Users and Groups

When using the LDAP Authenticator, credentials are authenticated at the time of login directly against the remote service. In order for Datameer to manage authorization and object permissions, a Datameer user entity is required to represent the remote user. It useful to think of users being imported into Datameer from LDAP with the remote server always ensuring that users have valid, active credentials. For details on how to add users from LDAP, see Importing Users. When a user is imported into Datameer, a user entity is created using the remote unique identifier as the Datameer username and populated with other account details, i.e email address.

During import, Datameer creates groups based on the groups contained in the LDAP directory. This allows the use of existing LDAP groups for Datameer access control as the group memberships are mirrored across systems. The users' group memberships and user details are updated on every login to ensure that any changes to authorization policies in LDAP are reflected in every Datameer session. Since we rely on LDAP groups when the LDAP Authenticator is in use, there is no facility to create groups within Datameer*. Datameer can handle at maximum 500 LDAP groups.

* See Using a Default LDAP Group for the one exception to this rule.

hadoop.security.auth_to_local=RULE:[1:$1@$0](.*@EC2.INTERNAL)s/(.*)@EC2.INTERNAL/$1/L RULE:[2:$1@$0](.*@EC2.INTERNAL)s/(.*)@EC2.INTERNAL/$1/L DEFAULT

Configuration

# You can set a super user account here that has the ADMIN role. This can be used to login even if
# the external authentication service doesn't work
das.superuser.enabled=true
das.superuser.username=superuser
das.superuser.password=password

To configure Datameer to use your LDAP or ActiveDirectory service, click the Admin tab, click Authentication on the left menu and click Edit. This presents you with the option to choose between the Internal Datameer User Management or a Remote Authentication System. Select Remote and pick ActiveDirectory/LDAP from the drop down list:

Next, you see the configuration settings for you remote authentication service:

The configuration settings are described below:

Active Directory

Choosing the Active Directory service type configures the advanced query options with settings appropriate for most Active Directory installations. Also, a different strategy is used to list a user's groups which is required by Active Directory. If the default settings aren't appropriate for your installation they can be changed in the Query Options section. See Advanced Configuration.

Advanced Configuration

To refine your authenticator configuration you can customize the settings Datameer uses when communicating with the remote service. Expand the Query Options form:

Configuration (As of Datameer version 6.3)

To configure Datameer to use your LDAP or Active Directory service, select the Admin tab, choose Authentication from the menu on the left of the screen, and click the Edit button. Select Remote Authentication System from the drop down list and then select ActiveDirectory/LDAP from the drop-down list under the Authentication System heading.

The authentication configuration settings for Active Directory and LDAP are displayed.

The default user values can be set when accessing multiple LDAP servers as the same user. If a default user/password is set, check the box under Server Connections that the default user values should be used to authenticate.

Enter the server configuration settings. 

Multiple LDAP server can be added. Click the Add Server Connection button after all values have been entered. Datameer validates the server and credentials and then provides a blank Server Connection settings form for additional servers.

User and group query options.

Group filters.

Importing Users/Groups

Once you have successfully configured your LDAP connection, you can now import users into Datameer, enabling users to access the system. Because AD/LDAP is active, Datameer's internal authentication method is disabled. Therefore, admins must create all groups needed in the AD and add the users there before importing them. To import, click Users from the Admin menu. 

From the Add Users and Groups from External Authenticator a list is populated with users/groups from the LDAP server. The search bar looks for a string contained in the User Name, email, or Group Name.

Select the user/group, assign a role, and click Add. Each user must have a role. Once a user/group has been added, the name is greyed out from the list. That user/group has access to Datameer once the cache has been refreshed.

Users/Groups that have been added from the LDAP server is displayed and can be edited.

Highlight multiple users/groups to to perform bulk role updates or deletions. It is also possible to bulk import users from your LDAP authenticator.

Advanced Topics

Cache settings

Datameer loads the entire set of LDAP users into a cache that is periodically refreshed from LDAP. This offers tremendous performance benefits and enables features like search and browse in the UI. By default, Datameer refreshes this cache every hour. This means that modification to LDAP data might not be reflected until the cache is refreshed.

To change the cache refresh settings you can set the system property ldap.authenticator.available.users.refresh.interval.minutes to whatever minute value you desire. For most installations, the 60 minute setting makes sense.

Enabling and disabling remote authentication

While setting up the system or when doing maintenance, you might find it necessary to switch off the LDAP Authenticator. When the LDAP Authenticator is disabled, all user's which were imported from LDAP are automatically disabled and the cache is dropped. When the authenticator is re-enabled, all users are then re-enabled and ready for use. You don't have to re-import any users. Also note that the cache has been re-built.

Skipping users

Datameer builds a list of all available users for import based on the authenticator configuration. During this process, Datameer dropS users from this list if:

• The user doesn't have a username
• The user doesn't have an email address
• The user isn't a member of a group (see Using a Default LDAP Group for a workaround)

If you don't see users that you are expecting available for import to Datameer, check your logs and look for WARN level message such as:

LdapUser has empty email address, will be filtered from available users :
LdapUser has empty username, will be filtered out from available users :
LdapUser has no groups and default group is disabled, will be filtered from available users :

Seeing these types of messages often signifies a misconfiguration.

Using a default LDAP group

By default when constructing the list of users available for import, Datameer skips any users that aren't members of a group in LDAP. This behavior is desirable since this is most likely a mis-configuration and Datameer requires user to belong to a group. However, it is possible that your LDAP users haven't been assigned to a group or that for some reason the Datameer authenticator can't resolve any. In this case, you can set a system property - ldap.authenticator.use.default.group=true - creating a default group for imported LDAP users. The group LDAP_USERS contains every user not assigned to another group, be aware of this when setting up group permissions.

Limiting LDAP user results

Many LDAP providers, Active Directory included, limit the number of results returned in most searches. When this limit it is reached, no more results are sent to the client in a single request. This is problematic, especially if you don't have the ability to configure the LDAP service to allow more results. If your LDAP installation is sufficiently large and your service is configured to limit results in this way, Datameer might fail to load any users at all. To get around this issue, Datameer offers several configuration options:

Use a more restrictive search base

In the Query Options section of the Authenticator configuration screen, you can define a search base that limits the scope of the LDAP query. For example, if we have a search base for a Datameer LDAP server DC=datameer,DC=local and it contains 3,000 users which is over the limit of 1,000 results, we can refine it to include only the organizational unit we want, OU=BarUnit,DC=Datameer,DC=local which contains only 1,000 users.

Now we can successfully import users from the organizational unit BarUnit and below in the LDAP tree.

Add constraints to the user definition

The Query Options section also contains a field for configuring a User Filter. This is analogous to an SQL WHERE clause used when Datameer queries for LDAP users. You can filter any attribute associated with a user in your LDAP server. As an example, we could filter users based on their membership in either the 'Finance' or 'IT' department. This would make only users matching the filter available for import into Datameer. The filter is defined using normal LDAP query syntax:

Set a custom MaxResults setting for the Datameer LDAP user

If the Datameer LDAP needs to list large numbers of users, a user specific setting can be applied in most LDAP providers. This would allow this specific user to exceed the default query result settings for this domain. In Active Directory, this is achieved by setting a MaxResults value for the Datameer LDAP user.