ADユーザーとグループを表示するには、nsswitch.confに何を追加する必要がありますか？

@Doug O'Nealがコメントで提案したように

enumerate = true

存在する/etc/sssd/sssd.conf。

これで、ADで定義されているすべてのユーザーとグループがgetent passwd表示されます。getent group

このオプションは通常推奨されません。からman sssd.conf：

(...)
    enumerate (bool)
       Determines if a domain can be enumerated. This parameter can have one of the
       following values:

       TRUE = Users and groups are enumerated

       FALSE = No enumerations for this domain

       Default: FALSE

       Note: Enabling enumeration has a moderate performance impact on SSSD while enumeration
       is running. It may take up to several minutes after SSSD startup to fully complete 
       enumerations. During this time, individual requests for information will go directly
       to LDAP, though it may be slow, due to the heavy enumeration processing. Saving a large 
       number of entries to cache after the enumeration completes might also be CPU intensive
       as the memberships have to be recomputed.

       While the first enumeration is running, requests for the complete user or group lists
       may return no results until it completes.

       Further, enabling enumeration may increase the time necessary to detect network
       disconnection, as longer timeouts are required to ensure that enumeration
       lookups are completed successfully. For more information, refer to the man pages for 
       the specific id_provider in use.

       For the reasons cited above, enabling enumeration is not recommended, especially in 
       large environments.
(...)