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Configuring ClickHouse to Use LDAP for Authentication and Role Mapping

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>
    note

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

    These are the basic settings used above:

    ParameterDescriptionExample
    hosthostname or IP of LDAP serverldap.forumsys.com
    portdirectory port for LDAP server389
    bind_dntemplate path to usersuid={user_name},dc=example,dc=com
    enable_tlswhether to use secure ldapno
    tls_require_certwhether to require certificate for connectionnever
    note

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

    note

    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:

    ParameterDescriptionExample
    serverlabel defined in the prior ldap_servers sectiontest_ldap_server
    rolesname of the roles defined in ClickHouse the users will be mapped toscientists_role
    base_dnbase path to start search for groups with userdc=example,dc=com
    search_filterldap search filter to identify groups to select for mapping users(&(objectClass=groupOfUniqueNames)(uniqueMember={bind_dn}))
    attributewhich attribute name should value be returned fromcn
  1. Restart your ClickHouse server to apply the settings.

2. Configure ClickHouse database roles and permissions​

note

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 :)
    note

    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

    β”Œβ”€name───────────────┐
    β”‚ INFORMATION_SCHEMA β”‚
    β”‚ db1_mysql β”‚
    β”‚ db2 β”‚
    β”‚ db3 β”‚
    β”‚ db4_mysql β”‚
    β”‚ db5_merge β”‚
    β”‚ default β”‚
    β”‚ information_schema β”‚
    β”‚ system β”‚
    β””β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”€β”˜

    9 rows in set. Elapsed: 0.004 sec.

Summary​

This article demostrated 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.