96 lines
3.5 KiB
XML
96 lines
3.5 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="sec-user-management">
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<title>User Management</title>
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<para>NixOS supports both declarative and imperative styles of user
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management. In the declarative style, users are specified in
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<filename>configuration.nix</filename>. For instance, the following
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states that a user account named <literal>alice</literal> shall exist:
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<programlisting>
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users.extraUsers.alice =
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{ createHome = true;
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home = "/home/alice";
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description = "Alice Foobar";
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extraGroups = [ "wheel" "networkmanager" ];
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useDefaultShell = true;
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openssh.authorizedKeys.keys = [ "ssh-dss AAAAB3Nza... alice@foobar" ];
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};
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</programlisting>
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Note that <literal>alice</literal> is a member of the
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<literal>wheel</literal> and <literal>networkmanager</literal> groups,
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which allows her to use <command>sudo</command> to execute commands as
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<literal>root</literal> and to configure the network, respectively.
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Also note the SSH public key that allows remote logins with the
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corresponding private key. Users created in this way do not have a
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password by default, so they cannot log in via mechanisms that require
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a password. However, you can use the <command>passwd</command> program
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to set a password, which is retained across invocations of
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<command>nixos-rebuild</command>.</para>
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<para>If you set users.mutableUsers to false, then the contents of /etc/passwd
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and /etc/group will be congruent to your NixOS configuration. For instance,
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if you remove a user from users.extraUsers and run nixos-rebuild, the user
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account will cease to exist. Also, imperative commands for managing users
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and groups, such as useradd, are no longer available.</para>
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<para>A user ID (uid) is assigned automatically. You can also specify
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a uid manually by adding
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<programlisting>
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uid = 1000;
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</programlisting>
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to the user specification.</para>
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<para>Groups can be specified similarly. The following states that a
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group named <literal>students</literal> shall exist:
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<programlisting>
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users.extraGroups.students.gid = 1000;
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</programlisting>
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As with users, the group ID (gid) is optional and will be assigned
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automatically if it’s missing.</para>
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<warning><para>Currently declarative user management is not perfect:
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<command>nixos-rebuild</command> does not know how to realise certain
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configuration changes. This includes removing a user or group, and
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removing group membership from a user.</para></warning>
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<para>In the imperative style, users and groups are managed by
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commands such as <command>useradd</command>,
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<command>groupmod</command> and so on. For instance, to create a user
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account named <literal>alice</literal>:
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<screen>
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$ useradd -m alice</screen>
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The flag <option>-m</option> causes the creation of a home directory
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for the new user, which is generally what you want. The user does not
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have an initial password and therefore cannot log in. A password can
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be set using the <command>passwd</command> utility:
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<screen>
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$ passwd alice
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Enter new UNIX password: ***
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Retype new UNIX password: ***
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</screen>
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A user can be deleted using <command>userdel</command>:
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<screen>
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$ userdel -r alice</screen>
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The flag <option>-r</option> deletes the user’s home directory.
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Accounts can be modified using <command>usermod</command>. Unix
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groups can be managed using <command>groupadd</command>,
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<command>groupmod</command> and <command>groupdel</command>.</para>
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</chapter>
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