400 lines
14 KiB
XML
400 lines
14 KiB
XML
<refentry 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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<refmeta>
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<refentrytitle><command>nixos-rebuild</command></refentrytitle>
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<manvolnum>8</manvolnum>
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<refmiscinfo class="source">NixOS</refmiscinfo>
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<!-- <refmiscinfo class="version"><xi:include href="version.txt" parse="text"/></refmiscinfo> -->
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</refmeta>
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<refnamediv>
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<refname><command>nixos-rebuild</command></refname>
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<refpurpose>reconfigure a NixOS machine</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<cmdsynopsis>
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<command>nixos-rebuild</command>
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<group choice='req'>
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<arg choice='plain'><option>switch</option></arg>
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<arg choice='plain'><option>boot</option></arg>
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<arg choice='plain'><option>test</option></arg>
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<arg choice='plain'><option>build</option></arg>
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<arg choice='plain'><option>dry-build</option></arg>
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<arg choice='plain'><option>dry-activate</option></arg>
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<arg choice='plain'><option>build-vm</option></arg>
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<arg choice='plain'><option>build-vm-with-bootloader</option></arg>
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</group>
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<sbr />
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<arg><option>--upgrade</option></arg>
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<arg><option>--install-bootloader</option></arg>
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<arg><option>--no-build-nix</option></arg>
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<arg><option>--fast</option></arg>
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<arg><option>--rollback</option></arg>
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<sbr />
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<arg>
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<group choice='req'>
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<arg choice='plain'><option>--profile-name</option></arg>
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<arg choice='plain'><option>-p</option></arg>
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</group>
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<replaceable>name</replaceable>
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</arg>
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<sbr />
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<arg><option>--show-trace</option></arg>
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</cmdsynopsis>
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</refsynopsisdiv>
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<refsection><title>Description</title>
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<para>This command updates the system so that it corresponds to the
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configuration specified in
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<filename>/etc/nixos/configuration.nix</filename>. Thus, every time
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you modify <filename>/etc/nixos/configuration.nix</filename> or any
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NixOS module, you must run <command>nixos-rebuild</command> to make
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the changes take effect. It builds the new system in
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<filename>/nix/store</filename>, runs its activation script, and stop
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and (re)starts any system services if needed.</para>
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<para>This command has one required argument, which specifies the
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desired operation. It must be one of the following:
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<variablelist>
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<varlistentry>
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<term><option>switch</option></term>
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<listitem>
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<para>Build and activate the new configuration, and make it the
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boot default. That is, the configuration is added to the GRUB
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boot menu as the default meny entry, so that subsequent reboots
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will boot the system into the new configuration. Previous
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configurations activated with <command>nixos-rebuild
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switch</command> or <command>nixos-rebuild boot</command> remain
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available in the GRUB menu.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>boot</option></term>
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<listitem>
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<para>Build the new configuration and make it the boot default
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(as with <command>nixos-rebuild switch</command>), but do not
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activate it. That is, the system continues to run the previous
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configuration until the next reboot.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>test</option></term>
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<listitem>
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<para>Build and activate the new configuration, but do not add
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it to the GRUB boot menu. Thus, if you reboot the system (or if
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it crashes), you will automatically revert to the default
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configuration (i.e. the configuration resulting from the last
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call to <command>nixos-rebuild switch</command> or
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<command>nixos-rebuild boot</command>).</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build</option></term>
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<listitem>
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<para>Build the new configuration, but neither activate it nor
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add it to the GRUB boot menu. It leaves a symlink named
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<filename>result</filename> in the current directory, which
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points to the output of the top-level “system” derivation. This
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is essentially the same as doing
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<screen>
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$ nix-build /path/to/nixpkgs/nixos -A system
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</screen>
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Note that you do not need to be <literal>root</literal> to run
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<command>nixos-rebuild build</command>.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>dry-build</option></term>
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<listitem>
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<para>Show what store paths would be built or downloaded by any
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of the operations above, but otherwise do nothing.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>dry-activate</option></term>
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<listitem>
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<para>Build the new configuration, but instead of activating it,
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show what changes would be performed by the activation (i.e. by
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<command>nixos-rebuild test</command>). For
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instance, this command will print which systemd units would be
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restarted. The list of changes is not guaranteed to be
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complete.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build-vm</option></term>
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<listitem>
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<para>Build a script that starts a NixOS virtual machine with
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the desired configuration. It leaves a symlink
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<filename>result</filename> in the current directory that points
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(under
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<filename>result/bin/run-<replaceable>hostname</replaceable>-vm</filename>)
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at the script that starts the VM. Thus, to test a NixOS
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configuration in a virtual machine, you should do the following:
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<screen>
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$ nixos-rebuild build-vm
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$ ./result/bin/run-*-vm
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</screen></para>
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<para>The VM is implemented using the <literal>qemu</literal>
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package. For best performance, you should load the
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<literal>kvm-intel</literal> or <literal>kvm-amd</literal>
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kernel modules to get hardware virtualisation.</para>
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<para>The VM mounts the Nix store of the host through the 9P
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file system. The host Nix store is read-only, so Nix commands
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that modify the Nix store will not work in the VM. This
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includes commands such as <command>nixos-rebuild</command>; to
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change the VM’s configuration, you must halt the VM and re-run
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the commands above.
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</para>
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<para>The VM has its own <literal>ext3</literal> root file
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system, which is automatically created when the VM is first
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started, and is persistent across reboots of the VM. It is
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stored in
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<literal>./<replaceable>hostname</replaceable>.qcow2</literal>.
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<!-- The entire file system hierarchy of the host is available in
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the VM under <filename>/hostfs</filename>.--></para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>build-vm-with-bootloader</option></term>
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<listitem>
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<para>Like <option>build-vm</option>, but boots using the
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regular boot loader of your configuration (e.g., GRUB 1 or 2),
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rather than booting directly into the kernel and initial ramdisk
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of the system. This allows you to test whether the boot loader
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works correctly. However, it does not guarantee that your NixOS
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configuration will boot successfully on the host hardware (i.e.,
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after running <command>nixos-rebuild switch</command>), because
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the hardware and boot loader configuration in the VM are
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different. The boot loader is installed on an automatically
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generated virtual disk containing a <filename>/boot</filename>
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partition, which is mounted read-only in the VM.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</para>
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</refsection>
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<refsection><title>Options</title>
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<para>This command accepts the following options:</para>
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<variablelist>
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<varlistentry>
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<term><option>--upgrade</option></term>
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<listitem>
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<para>Fetch the latest version of NixOS from the NixOS
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channel.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--install-bootloader</option></term>
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<listitem>
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<para>Causes the boot loader to be (re)installed on the
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device specified by the relevant configuration options.
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</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--no-build-nix</option></term>
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<listitem>
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<para>Normally, <command>nixos-rebuild</command> first builds
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the <varname>nixUnstable</varname> attribute in Nixpkgs, and
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uses the resulting instance of the Nix package manager to build
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the new system configuration. This is necessary if the NixOS
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modules use features not provided by the currently installed
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version of Nix. This option disables building a new Nix.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--fast</option></term>
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<listitem>
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<para>Equivalent to <option>--no-build-nix</option>
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<option>--show-trace</option>. This option is useful if you
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call <command>nixos-rebuild</command> frequently (e.g. if you’re
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hacking on a NixOS module).</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--rollback</option></term>
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<listitem>
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<para>Instead of building a new configuration as specified by
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<filename>/etc/nixos/configuration.nix</filename>, roll back to
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the previous configuration. (The previous configuration is
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defined as the one before the “current” generation of the
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Nix profile <filename>/nix/var/nix/profiles/system</filename>.)</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--profile-name</option></term>
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<term><option>-p</option></term>
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<listitem>
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<para>Instead of using the Nix profile
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<filename>/nix/var/nix/profiles/system</filename> to keep track
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of the current and previous system configurations, use
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<filename>/nix/var/nix/profiles/system-profiles/<replaceable>name</replaceable></filename>.
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When you use GRUB 2, for every system profile created with this
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flag, NixOS will create a submenu named “NixOS - Profile
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'<replaceable>name</replaceable>'” in GRUB’s boot menu,
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containing the current and previous configurations of this
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profile.</para>
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<para>For instance, if you want to test a configuration file
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named <filename>test.nix</filename> without affecting the
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default system profile, you would do:
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<screen>
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$ nixos-rebuild switch -p test -I nixos-config=./test.nix
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</screen>
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The new configuration will appear in the GRUB 2 submenu “NixOS - Profile
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'test'”.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--build-host</option></term>
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<listitem>
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<para>Instead of building the new configuration locally, use the
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specified host to perform the build. The host needs to be accessible
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with ssh, and must be able to perform Nix builds. If the option
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<option>--target-host</option> is not set, the build will be copied back
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to the local machine when done.</para>
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<para>Note that, if <option>--no-build-nix</option> is not specified,
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Nix will be built both locally and remotely. This is because the
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configuration will always be evaluated locally even though the building
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might be performed remotely.</para>
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<para>You can include a remote user name in
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the host name (<replaceable>user@host</replaceable>). You can also set
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ssh options by defining the <envar>NIX_SSHOPTS</envar> environment
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variable.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><option>--target-host</option></term>
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<listitem>
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<para>Specifies the NixOS target host. By setting this to something other
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than <replaceable>localhost</replaceable>, the system activation will
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happen on the remote host instead of the local machine. The remote host
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needs to be accessible over ssh, and for the commands
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<option>switch</option>, <option>boot</option> and <option>test</option>
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you need root access.</para>
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<para>If <option>--build-host</option> is not explicitly
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specified, <option>--build-host</option> will implicitly be set to the
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same value as <option>--target-host</option>. So, if you only specify
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<option>--target-host</option> both building and activation will take
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place remotely (and no build artifacts will be copied to the local
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machine).</para>
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<para>You can include a remote user name in
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the host name (<replaceable>user@host</replaceable>). You can also set
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ssh options by defining the <envar>NIX_SSHOPTS</envar> environment
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variable.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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<para>In addition, <command>nixos-rebuild</command> accepts various
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Nix-related flags, including <option>--max-jobs</option> /
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<option>-j</option>, <option>--show-trace</option>,
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<option>--keep-failed</option>, <option>--keep-going</option> and
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<option>--verbose</option> / <option>-v</option>. See
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the Nix manual for details.</para>
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</refsection>
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<refsection><title>Environment</title>
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<variablelist>
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<varlistentry>
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<term><envar>NIXOS_CONFIG</envar></term>
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<listitem>
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<para>Path to the main NixOS configuration module. Defaults to
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<filename>/etc/nixos/configuration.nix</filename>.</para>
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</listitem>
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</varlistentry>
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<varlistentry><term><envar>NIX_SSHOPTS</envar></term>
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<listitem><para>Additional options to be passed to
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<command>ssh</command> on the command line.</para></listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection><title>Files</title>
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<variablelist>
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<varlistentry>
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<term><filename>/run/current-system</filename></term>
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<listitem>
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<para>A symlink to the currently active system configuration in
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the Nix store.</para>
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</listitem>
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</varlistentry>
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<varlistentry>
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<term><filename>/nix/var/nix/profiles/system</filename></term>
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<listitem>
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<para>The Nix profile that contains the current and previous
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system configurations. Used to generate the GRUB boot
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menu.</para>
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</listitem>
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</varlistentry>
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</variablelist>
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</refsection>
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<refsection><title>Bugs</title>
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|
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<para>This command should be renamed to something more
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descriptive.</para>
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</refsection>
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</refentry>
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