An ansible role which configures direct Active Directory integration.

Supported Distributions

• RHEL7+, CentOS7+
• Fedora

Requirements

In order to join to the domain, you must use an Active Directory user which has sufficient join permissions. It is not recommended to use the Administrator user as the security footprint of this user is too large.

See Delegated Permissions for the explicit permissions a user must have.

Time must be in sync with Active Directory servers. The ad_integration role will use the timesync system role for this if the user specifies ad_integration_manage_timesync to true and provides a value for ad_integration_timesync_source to use as a timesource.

RHEL8 (and newer) and Fedora no longer support RC4 encryption out of the box, it is recommended to enable AES in Active Directory, if not possible then the AD-SUPPORT crypto policy must be enabled. The integration role will use the crypto_policies system role for this if the user sets the ad_integration_manage_crypto_policies and ad_integration_allow_rc4_crypto parameters to true.

The Linux system must be able to resolve default AD DNS SRV records.

The following firewall ports must be opened on the AD server side, reachable from the Linux client.

Role Variables

Required variables

ad_integration_realm

Active Directory realm, or domain name to join

ad_integration_password

The password of the user used to authenticate with when joining the machine to the realm. Do not use cleartext - use Ansible Vault to encrypt the value.

Optional variables

ad_integration_user

The user name to be used to authenticate with when joining the machine to the realm.

Default: Administrator

ad_integration_join_to_dc

an Active Directory domain controller's hostname (do not use IP address) may be specified to join via that domain controller directly.

Default: Not set

ad_integration_force_rejoin

Leave existing domain prior to performing join. This might be needed if the keytab is unable to authenticate with the machine account to the AD domain.

Default: false

ad_integration_auto_id_mapping

perform automatic UID/GID mapping for users and groups, set to false to rely on POSIX attributes already present in Active Directory.

Default: true

ad_integration_client_software

Only join realms for which we can use the given client software. Possible values include sssd or winbind. Not all values are supported for all realms.

Default: Automatic selection

ad_integration_membership_software

The software to use when joining to the realm. Possible values include samba or adcli. Not all values are supported for all realms.

Default: Automatic selection

ad_integration_computer_ou

The distinguished name of an organizational unit to create the computer account. It can be relative to the Root DSE, or a complete LDAP DN.

Default: Default AD computer container

ad_integration_manage_timesync

If true, the ad_integration role will use fedora.linux_system_roles.timesync. Requires providing a value for ad_integration_timesync_source to use as a time source.

Default: false

ad_integration_timesync_source

Hostname or IP address of time source to synchronize the system clock with. Providing this variable automatically sets ad_integration_manage_timesync to true.

ad_integration_manage_crypto_policies

If true, the ad_integration role will use fedora.linux_system_roles.crypto_policies as needed

Default: false

ad_integration_allow_rc4_crypto

If true, the ad_integration role will set the crypto policy allowing RC4 encryption. Providing this variable automatically sets ad_integration_manage_crypto_policies to true

Default: false

ad_integration_manage_dns

If true, the ad_integration role will use fedora.linux_system_roles.network to add the provided dns server (see below) with manual DNS configuration to an existing connection. If true then the following variables are required:

• ad_integration_dns_server - DNS server to add
• ad_integration_dns_connection_name - Existing network connection name to configure
• ad_integration_dns_connection_type - Existing network connection type to configure

ad_integration_dns_server

IP address of DNS server to add to existing networking configuration. Only applicable if ad_integration_manage_dns is true

ad_integration_dns_connection_name

The name option identifies the connection profile to be configured by the network role. It is not the name of the networking interface for which the profile applies. Only applicable if ad_integration_manage_dns is true

ad_integration_dns_connection_type

Network connection type such as ethernet, bridge, bond...etc, the network role contains a list of possible values. Only applicable if ad_integration_manage_dns is true

ad_dyndns_update

If true, SSSD is configured to automatically update the AD DNS server with the IP address of the client.

Default: false

ad_dyndns_ttl

Optional. The TTL, in seconds, to apply to the client's DNS record when updating it. Only applicable if ad_dyndns_update is true

Note: This will override the TTL set by an administrator on the server.

Default: 3600

ad_dyndns_iface

Optional. Interface or a list of interfaces whose IP addresses should be used for dynamic DNS updates. Special value "*" implies all IPs from all interfaces should be used. Only applicable if ad_dyndns_update is true

Default: Use the IP addresses of the interface which is used for AD LDAP connection

ad_dyndns_refresh_interval

Optional. How often should, in seconds, periodic DNS updates be performed in addition to when the back end goes online. Only applicable if ad_dyndns_update is true

Note: lowest possible value is 60 seconds. If value less than 60 is specified sssd will assume lowest value only.

Default: 86400

ad_dyndns_update_ptr

Optional. If true, the PTR record should also be explicitly updated. Only applicable if ad_dyndns_update is true

Default: true

ad_dyndns_force_tcp

Optional. If true, the nsupdate utility should default to using TCP for communicating with the DNS server. Only applicable if ad_dyndns_update is true

Default: false

ad_dyndns_auth

Optional. If true, GSS-TSIG authentication will be used for secure updates with the DNS server when updating A and AAAA records. Only applicable if ad_dyndns_update is true

Default: true

ad_dyndns_server

Optional. DNS server to use when performing a DNS update when autodetection settings fail. Only applicable if ad_dyndns_update is true

Default: None (let nsupdate choose the server)

ad_integration_join_parameters

Additional parameters (as a string) supplied directly to the realm join command. Useful if some specific configuration like --user-principal=host/name@REALM or --use-ldaps is needed. See man realm for details. Example: ad_integration_join_parameters: "--user-principal host/client007@EXAMPLE.COM"

Example Playbook

The following is an example playbook to setup direct Active Directory integration with AD domain domain.example.com, the join will be performed with user Administrator using the vault stored password. Prior to the join, the crypto policy for AD SUPPORT with RC4 encryption allowed will be set.

- hosts: all
  vars:
    ad_integration_realm: "domain.example.com"
    ad_integration_password: !vault | …vault encrypted password…
    ad_integration_manage_crypto_policies: true
    ad_integration_allow_rc4_crypto: true
  roles:
    - fedora.linux_system_roles.ad_integration

License

MIT.

Author Information

Justin Stephenson (jstephen@redhat.com)