Configuring ClickHouse to use LDAP for authentication and role mapping

Describes how to configure ClickHouse to use LDAP for authentication and role mapping

This page isn’t applicable to ClickHouse Cloud. The feature documented here isn’t available in ClickHouse Cloud services. See the ClickHouse Cloud Compatibility guide for more information.

ClickHouse can be configured to use LDAP to authenticate ClickHouse database users. This guide provides a simple example of integrating ClickHouse with an LDAP system authenticating to a publicly available directory.

1. Configure LDAP connection settings in ClickHouse

   1. Test your connection to this public LDAP server:

      $ ldapsearch -x -b dc=example,dc=com -H ldap://ldap.forumsys.com
      

      The reply will be something like this:

      # extended LDIF
      #
      # LDAPv3
      # base <dc=example,dc=com> with scope subtree
      # filter: (objectclass=*)
      # requesting: ALL
      #
      
      # example.com
      dn: dc=example,dc=com
      objectClass: top
      objectClass: dcObject
      objectClass: organization
      o: example.com
      dc: example
      ...
      

   2. Edit the config.xml file and add the following to configure LDAP:

      <ldap_servers>
          <test_ldap_server>
          <host>ldap.forumsys.com</host>
          <port>389</port>
          <bind_dn>uid={user_name},dc=example,dc=com</bind_dn>
          <enable_tls>no</enable_tls>
          <tls_require_cert>never</tls_require_cert>
          </test_ldap_server>
      </ldap_servers>
      

   The <test_ldap_server> tags is an arbitrary label to identify a particular LDAP server.

   These are the basic settings used above:

   Parameter	Description	Example
   host	hostname or IP of LDAP server	ldap.forumsys.com
   port	directory port for LDAP server	389
   bind_dn	template path to users	uid={user_name},dc=example,dc=com
   enable_tls	whether to use secure ldap	no
   tls_require_cert	whether to require certificate for connection	never

   In this example, since the public server uses 389 and doesn’t use a secure port, we disable TLS for demonstration purposes.

   View the LDAP doc page for more details on the LDAP settings.

   3. Add the <ldap> section to <user_directories> section to configure the user role mapping. This section defines when a user is authenticated and what role the user will receive. In this basic example, any user authenticating to LDAP will receive the scientists_role which will be defined at a later step in ClickHouse. The section should look similar to this:

      <user_directories>
          <users_xml>
              <path>users.xml</path>
          </users_xml>
          <local_directory>
              <path>/var/lib/clickhouse/access/</path>
          </local_directory>
          <ldap>
                <server>test_ldap_server</server>
                <roles>
                   <scientists_role />
                </roles>
                <role_mapping>
                   <base_dn>dc=example,dc=com</base_dn>
                   <search_filter>(&amp;(objectClass=groupOfUniqueNames)(uniqueMember={bind_dn}))</search_filter>
                   <attribute>cn</attribute>
                </role_mapping>
          </ldap>
      </user_directories>
      

      These are the basic settings used above:

      Parameter	Description	Example
      server	label defined in the prior ldap_servers section	test_ldap_server
      roles	name of the roles defined in ClickHouse the users will be mapped to	scientists_role
      base_dn	base path to start search for groups with user	dc=example,dc=com
      search_filter	ldap search filter to identify groups to select for mapping users	(&(objectClass=groupOfUniqueNames)(uniqueMember={bind_dn}))
      attribute	which attribute name should value be returned from	cn

   4. Restart your ClickHouse server to apply the settings.

2. Configure ClickHouse database roles and permissions

   The procedures in this section assumes that SQL Access Control and Account Management in ClickHouse has been enabled. To enable, view the SQL Users and Roles guide.

   1. Create a role in clickhouse with the same name used in the role mapping section of the config.xml file

      CREATE ROLE scientists_role;
      

   2. Grant needed privileges to the role. The following statement grants admin privileges to any user able to authenticate through LDAP:

      GRANT ALL ON *.* TO scientists_role;
      
3. Test the LDAP configuration

   1. Login using the ClickHouse client
      $ clickhouse-client --user einstein --password password
      ClickHouse client version 22.2.2.1.
      Connecting to localhost:9000 as user einstein.
      Connected to ClickHouse server version 22.2.2 revision 54455.
      
      chnode1 :)
      

   Use the ldapsearch command in step 1 to view all of the users available in the directory and for all of the users the password is password

   2. Test that the user was mapped correctly to the scientists_role role and has admin permissions

      SHOW DATABASES
      
      Query id: 93b785ff-1482-4eda-95b0-b2d68b2c5e0f
      
      ┌─name───────────────┐
      │ INFORMATION_SCHEMA │
      │ db1_mysql          │
      │ db2                │
      │ db3                │
      │ db4_mysql          │
      │ db5_merge          │
      │ default            │
      │ information_schema │
      │ system             │
      └────────────────────┘
      
      9 rows in set. Elapsed: 0.004 sec.
      

Summary

This article demonstrated the basics of configuring ClickHouse to authenticate to an LDAP server and also to map to a role. There are also options for configuring individual users in ClickHouse but having those users be authenticated by LDAP without configuring automated role mapping. The LDAP module can also be used to connect to Active Directory.