ncm-accounts: NCM component to manage the local accounts on the machine.


The accounts component manages the local accounts on a machine. LDAP authentication depends on the LDAP configuration, which is handled by ncm-authconfig.

Shadowing of passwords is also controlled by ncm-authconfig.


accounts provides several functions as an API to handle creation of users and groups. They are mainly targeted at helping creating consistent accounts across machines, using a central definition of all accounts and a per machine list of accounts to be actually created.

All these functions update a structure_accounts (return value may be assigned to "/software/components/accounts").

Behaviour of these functions can be customized by definining some variables before calling them, mainly :


    defines default root for home directory (D: /home)


    defines if home directory must be created by default (D : true)


    defines if a group must be defined with the same name as the user, if no group has been explicitly specified (D: true).


    defines if the default group must be created if it doesn't exist, with a gid equals to uid (D: true)


    defines a default value for user comment (D: "Created by ncm-accounts")


    defines a default value for group comment (D: "Created by ncm-accounts")

create_accounts_from_db(userList:nlist, users:list:optional, accountType:optional)

This function creates users or groups from a nlist containing user or group characteristics. It updates a structure_accounts (return value may be assigned to "/software/components/accounts").

User/group characteristics must be provided as structure_userinfo/structure_groupinfo.

Second parameter, if presents, gives the list of users to create from user_list. This allows to use a unique user/group definition for all nodes, to warrant consistency between nodes.

By default (accountType undefined or 0), this function creates user accounts. To create groups, set third parameter (accountType) to 1.

create_group(groupname:string, params:structure_groupinfo)

This function creates a group, applying some defaults defined by variables and checking information consistency. It updates a structure_accounts (return value may be assigned to "/software/components/accounts").

create_user(username:string, params:structure_userinfo)

This function creates a user, applying some defaults defined by variables and checking information consistency (e.g. group existence). It updates a structure_accounts (return value may be assigned to "/software/components/accounts").

keep_user_group(user_or_group:string or list of string)

This functions adds a user or group to the kept_users or kept_groups resources. The argument can be a string or list of strings. The return value can be assigned to /software/components/accounts/kept_users or /software/components/accounts/kept_groups.



The crypted root password for the machine.


An nlist of users to configure on the node. The key is the account name (or base name for pool accounts). The numerical UID is mandatory. The available fields are:

  • comment

    real name or comment about user. Defaults to user name itself.

  • homeDir

    full path of the home directory of the user. Defaults to the system default. For pool accounts this will be used as a base for creating numbered home directories; if this is not set the username will be used as a base.

  • createHome

    boolean indicating whether to create a home directory for the user. Defaults to false.

  • groups

    a list of groups for this user. The first group listed is the primary group. If this is not given, then it will default to a group named identically to the user name. NOTE: If this group already exists, then the command to add the user will fail.

  • password

    the crypted password entry for the user. No default. If not given it will result in a locked account, except if the account already exists and has a defined password: in this case, it will be kept.

  • shell

    the shell for the user. If it is defined as an empty string, the current shell is preserved for an existing account (for a new account, it will remain undefined, meaning that the default shell on the system will be used).

    Defaults to /bin/bash.

  • uid

    the uid value for this account. Mandatory. This is interpreted as the base uid value for pool accounts (i.e. poolSize > 0).

  • poolStart

    the index at which to start the pool accounts. The default is 0. This must be a non-negative number.

  • poolDigits

    the number of digits to which the pool account numbers are padded. For example a value of 3 will create accounts atlas000, atlas001, etc. The default is the number of digits in the highest-numbered pool account.

  • poolSize

    number of pool accounts to create. The default is 0 which indicates that it is a normal (unique) account. A value greater than 0 will create a set of numbered accounts with the given user name as a base. E.g. a base name of "atlas" and a poolSize=3 will create three accounts atlas0 atlas1 atlas2.


An nlist of groups to configure on the node. The key is the group name. At least one field must be specified.

  • comment

    ignored, but provided so gid doesn't have to be

  • gid

    the optional gid number for the group

  • requiredMembers

    An optional list of users that must be added as member of the group. The users don't have to be local users, defined in the configuration.

    Note 1: group members present in the /etc/group file but not defined in the current configuration are removed by ncm-accounts if they are not required members.

    Note 2: for users defined in the configuration the preferred way to add them to groups is by defining their groups property.

  • replaceMembers (boolean)

    When true, current members of the group (if existing) are replaced by the groups defined in the configuration (coming from requiredMembers and user groups). If false, groups from the configuration are merged with existing ones.

    D: false


A nlist of values to be set in /etc/login.defs. NOTE: This configuration file is specific to RedHat-like systems; setting will be ignored on other systems. This file configures all kinds of default settings such as:

  • uid_min, uid_max

    Min/max values for automatic uid selection in useradd

  • gid_min, gid_max

    Min/max values for automatic gid selection in groupadd

  • pass_max_days

    Maximum number of days a password may be used.

  • pass_min_days

    Minimum number of days allowed between password changes.

  • pass_min_len

    Minimum acceptable password length.

  • pass_warn_age

    Number of days warning given before a password expires.

  • create_home

    If useradd should create home directories for users by default


Flag to indicate whether unknown accounts should be deleted. The default is false. The root account can never be removed.


This property may have 3 values: 'none', 'system', 'dyn_user_group'. It controls the accounts/groups that have to be preserved when 'remove_unknown' is true (it has no effect when remove_unknown=false).

The effect of each possible value is

  • system

    all accounts/groups in the system range (strictly below GID/UID_MIN as defined in /etc/login.defs) are preserved even though they are not present in the configuration. It is possible to use login_defs/uid_min and login_defs/gid_min properties to control the preserved ranges.

  • dyn_user_group

    all accounts/groups in the system range and in the range used for dynamic uid/gid allocation by useradd command, ie. all accounts/groups with uid/gid less or equal to GID/UID_MAX as defined in /etc/login.defs, are preserved. The exact list of accounts preserved depends on UID/GID_MAX value. It is possible to use login_defs/uid_max and login_defs/gid_max properties to control the preserved ranges. Not that remove_unknown=true with preserved_accounts=dyn_user_group and UID/GID_MAX set to the highest possible IDs is equivalent to remove_unknown=false.

  • none

    all existing accounts/groups not present in the configuration are removed from the system (except root).

Default: dyn_user_group


Local users belonging to LDAP groups

When a local user has to belong to a group defined only on LDAP, a local group with the desired numerical ID is created.

This group has the same name as the user ID. It will be removed on the next run of the component if remove_unknown is set to true. This is somewhat ugly, but doesn't affect the system behaviour at all, so it won't be fixed.

nsswitch.conf status

The component has been tested with files as the primary source on /etc/nsswitch.conf for group and passwd. Different settings may produce strange behaviour. These settings are not controlled by ncm-accounts but by ncm-authconfig.