nixpkgs/nixos/doc/manual/development/building-parts.xml
Samuel Dionne-Riel 88ca2b1ec4 nixos/doc: ran make format
With visual inspection that nothing got worse.
2018-05-31 21:03:51 -04:00

122 lines
3.8 KiB
XML
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

<chapter xmlns="http://docbook.org/ns/docbook"
xmlns:xlink="http://www.w3.org/1999/xlink"
xmlns:xi="http://www.w3.org/2001/XInclude"
version="5.0"
xml:id="sec-building-parts">
<title>Building Specific Parts of NixOS</title>
<para>
With the command <command>nix-build</command>, you can build specific parts
of your NixOS configuration. This is done as follows:
<screen>
$ cd <replaceable>/path/to/nixpkgs/nixos</replaceable>
$ nix-build -A config.<replaceable>option</replaceable></screen>
where <replaceable>option</replaceable> is a NixOS option with type
“derivation” (i.e. something that can be built). Attributes of interest
include:
<variablelist>
<varlistentry>
<term>
<varname>system.build.toplevel</varname>
</term>
<listitem>
<para>
The top-level option that builds the entire NixOS system. Everything else
in your configuration is indirectly pulled in by this option. This is
what <command>nixos-rebuild</command> builds and what
<filename>/run/current-system</filename> points to afterwards.
</para>
<para>
A shortcut to build this is:
<screen>
$ nix-build -A system</screen>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>system.build.manual.manual</varname>
</term>
<listitem>
<para>
The NixOS manual.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>system.build.etc</varname>
</term>
<listitem>
<para>
A tree of symlinks that form the static parts of
<filename>/etc</filename>.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>system.build.initialRamdisk</varname>
</term>
<term>
<varname>system.build.kernel</varname>
</term>
<listitem>
<para>
The initial ramdisk and kernel of the system. This allows a quick way to
test whether the kernel and the initial ramdisk boot correctly, by using
QEMUs <option>-kernel</option> and <option>-initrd</option> options:
<screen>
$ nix-build -A config.system.build.initialRamdisk -o initrd
$ nix-build -A config.system.build.kernel -o kernel
$ qemu-system-x86_64 -kernel ./kernel/bzImage -initrd ./initrd/initrd -hda /dev/null
</screen>
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>system.build.nixos-rebuild</varname>
</term>
<term>
<varname>system.build.nixos-install</varname>
</term>
<term>
<varname>system.build.nixos-generate-config</varname>
</term>
<listitem>
<para>
These build the corresponding NixOS commands.
</para>
</listitem>
</varlistentry>
<varlistentry>
<term>
<varname>systemd.units.<replaceable>unit-name</replaceable>.unit</varname>
</term>
<listitem>
<para>
This builds the unit with the specified name. Note that since unit names
contain dots (e.g. <literal>httpd.service</literal>), you need to put
them between quotes, like this:
<screen>
$ nix-build -A 'config.systemd.units."httpd.service".unit'
</screen>
You can also test individual units, without rebuilding the whole system,
by putting them in <filename>/run/systemd/system</filename>:
<screen>
$ cp $(nix-build -A 'config.systemd.units."httpd.service".unit')/httpd.service \
/run/systemd/system/tmp-httpd.service
# systemctl daemon-reload
# systemctl start tmp-httpd.service
</screen>
Note that the unit must not have the same name as any unit in
<filename>/etc/systemd/system</filename> since those take precedence over
<filename>/run/systemd/system</filename>. Thats why the unit is
installed as <filename>tmp-httpd.service</filename> here.
</para>
</listitem>
</varlistentry>
</variablelist>
</para>
</chapter>