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Chapter 13. Managing User and Host Groups

13.1. How User and Host Groups Work in IdM

13.1.1. What User and Host Groups Are

A user group is a set of users with common privileges, password policies, and other characteristics.
A host group is a set of IdM hosts with common access control rules and other characteristics.
For example, you can define groups around company departments, physical locations, or access control requirements.

13.1.2. Supported Group Members

A user group in IdM can include:
  • IdM users
  • other IdM user groups
  • external users, which are users that exist outside IdM
A host group in IdM can include:
  • IdM servers and clients
  • other IdM host groups

13.1.3. Direct and Indirect Group Members

User and host group attributes in IdM apply to both direct and indirect members: when group B is a member of group A, all users in group B are considered members of group A.
For example, in Figure 13.1, “Direct and Indirect Group Membership”:
  • User 1 and User 2 are direct members of group A.
  • User 3, User 4, and User 5 are indirect members of group A.
Direct and Indirect Group Membership

Figure 13.1. Direct and Indirect Group Membership

If you set a password policy for user group A, the policy applies to all users in user group B as well.

Example 13.1. Viewing Direct and Indirect Group Members

  1. Create two groups: group_A and group_B. See Section 13.2, “Adding and Removing User or Host Groups”.
  2. Add:
    • one user as a member of group_A
    • another user as a member of group_B
    • group_B as a member of group_A
    See Section 13.3, “Adding and Removing User or Host Group Members”.
  3. In the web UI: Select Identity → Groups. From the individual group types which are listed in a side bar on the left, select User Groups, and click the name of group_A. Switch between Direct Membership and Indirect Membership.
    Indirect and Direct Members

    Figure 13.2. Indirect and Direct Members

  4. From the command line: Use the ipa group-show command: 
    $ ipa group-show group_A
  ...
  Member users: user_1
  Member groups: group_B
  Indirect Member users: user_2
The list of indirect members does not include external users from trusted Active Directory domains. The Active Directory trust user objects are not visible in the IdM interface because they do not exist as LDAP objects within IdM.

13.1.4. User Group Types in IdM

POSIX groups (the default)
POSIX groups support POSIX attributes for their members. Note that groups that interact with Active Directory cannot use POSIX attributes.
Non-POSIX groups
All group members of this type of group must belong to the IdM domain.
External groups
External groups allow adding group members that exist in an identity store outside of the IdM domain. The external store can be a local system, an Active Directory domain, or a directory service.
Non-POSIX and external groups do not support POSIX attributes. For example, these groups do not have a GID defined.

Example 13.2. Searching for Different Types of User Groups

  1. Run the ipa group-find command to display all user groups.
  2. Run the ipa group-find --posix command to display all POSIX groups.
  3. Run the ipa group-find --nonposix command to display all non-POSIX groups.
  4. Run the ipa group-find --external command to display all external groups.

13.1.5. User and Host Groups Created by Default

Table 13.1. User and Host Groups Created by Default

Group Name User or Host Default Group Members
ipausers User group All IdM users
admins User group Users with administrative privileges, initially the default admin user
editors User group Users allowed to edit other IdM users in the web UI, without all the rights of an administrative user
trust admins User group Users with privileges to manage Active Directory trusts
ipaservers Host group All IdM server hosts
Adding a user to a user group applies the privileges and policies associated with the group. For example, adding a user to the admins group grants the user administrative privileges.

Warning

Do not delete the admins group. As admins is a pre-defined group required by IdM, this operation causes problems with certain commands.

Warning

Be careful when adding hosts to the ipaservers host group. All hosts in ipaservers have the ability to promote themselves to an IdM server.
In addition, IdM creates user private groups by default whenever a new user is created in IdM.
  • The user private group has the same name as the user for which it was created.
  • The user is the only member of the user private group.
  • GID of the private groups matches the UID of the user.

Example 13.3. Viewing User Private Groups

Run the ipa group-find --private command to display all user private groups: 
$ ipa group-find --private
----------------
2 groups matched
----------------
  Group name: user1
  Description: User private group for user1
  GID: 830400006

  Group name: user2
  Description: User private group for user2
  GID: 830400004
----------------------------
Number of entries returned 2
----------------------------
In some situations, it is better to avoid creating user private groups, such as when a NIS group or another system group already uses the GID that would be assigned to the user private group. See Section 13.4, “Disabling User Private Groups”.