Chapter 4. Installing Directory Server with Kerberos authentication behind a load balancer

Procedure

1. Enable the redhat-ds:12 module and install Directory Server packages:

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   # dnf module enable redhat-ds:12
   # dnf install 389-ds-base cockpit-389-ds

Procedure

1. Use the dscreate create-template command to create a template .inf file. For example, to store the template in the /root/instance_name.inf file, enter:

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   # dscreate create-template /root/instance_name.inf

   The created file contains all available parameters including descriptions.

2. Edit the file that you created in the previous step:

   1. Uncomment the parameters that you want to set to customize the installation.

      All parameters have defaults. However, customize certain parameters for a production environment. For example, set at least the following parameters in the [slapd] section:

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      instance_name = instance_name
      root_password = password

      To install an instance with the LMDB backend, set the following parameters:

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      db_lib = mdb
      mdb_max_size = 21474836480

      Note that mdb_max_size must be an integer value that depends on your directory size. For more details, see nsslapd-mdb-max-size attribute description.

   2. To use the instance behind a load balancer with GSSAPI authentication, set the full_machine_name parameter in the [general] section to the fully-qualified domain name (FQDN) of the load balancer instead of the FQDN of the Directory Server host:

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      full_machine_name = loadbalancer.example.com

   3. Uncomment the strict_host_checking parameter in the [general] section and set it to False:

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      strict_host_checking = False

   4. To automatically create a suffix during instance creation, set the following parameters in the [backend-userroot] section:

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      create_suffix_entry = True
      suffix = dc=example,dc=com

      Important

      If you do not create a suffix during instance creation, you must create it later manually before you can store data in this instance.

   5. Optional: Uncomment other parameters and set them to appropriate values for your environment. For example, use these parameters to specify replication options, such as authentication credentials and changelog trimming, or set different ports for the LDAP and LDAPS protocols.

      Note

      By default, new instances that you create include a self-signed certificate and TLS enabled. For increased security, do not disable this feature. Note that you can replace the self-signed certificate with a certificate issued by a Certificate Authority (CA) at a later date.

Procedure

1. Pass the .inf file to the dscreate from-file command to create the new instance:

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   # dscreate from-file /root/instance_name.inf
   Starting installation ...
   Validate installation settings ...
   Create file system structures ...
   Create self-signed certificate database ...
   Perform SELinux labeling ...
   Perform post-installation tasks ...
   Completed installation for instance: slapd-instance_name

   The dscreate utility automatically starts the instance and configures RHEL to start the service when the system boots.

2. Open the required ports in the firewall:

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   # firewall-cmd --permanent --add-port={389/tcp,636/tcp}

3. Reload the firewall configuration:

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   # firewall-cmd --reload

Procedure

1. Create the Kerberos principal for the load balancer, for example ldap/loadbalancer.example.com_@_EXAMPLE.COM. The procedure to create the service principal depends on your Kerberos installation. For details, see your Kerberos server’s documentation.
2. Optional: You can add further principals to the keytab file. For example, to enable users to connect to the Directory Server instance behind the load balancer directly using Kerberos authentication, add additional principals for the Directory Server host. For example, ldap/server1.example.com@EXAMPLE.COM.
3. Copy the service keytab file to the Directory Server host, and store it, for example, in the /etc/dirsrv/slapd-instance_name/ldap.keytab file.

4. Add the path to the service keytab to the /etc/sysconfig/slapd-instance_name file:

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   KRB5_KTNAME=/etc/dirsrv/slapd-instance_name/ldap.keytab

5. Restart the Directory Server instance:

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   # dsctl instance_name restart