123 lines
4.5 KiB
XML
123 lines
4.5 KiB
XML
<section 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-imperative-containers">
|
||
<title>Imperative Container Management</title>
|
||
|
||
<para>
|
||
We’ll cover imperative container management using
|
||
<command>nixos-container</command> first. Be aware that container management
|
||
is currently only possible as <literal>root</literal>.
|
||
</para>
|
||
|
||
<para>
|
||
You create a container with identifier <literal>foo</literal> as follows:
|
||
<screen>
|
||
# nixos-container create foo
|
||
</screen>
|
||
This creates the container’s root directory in
|
||
<filename>/var/lib/containers/foo</filename> and a small configuration file
|
||
in <filename>/etc/containers/foo.conf</filename>. It also builds the
|
||
container’s initial system configuration and stores it in
|
||
<filename>/nix/var/nix/profiles/per-container/foo/system</filename>. You can
|
||
modify the initial configuration of the container on the command line. For
|
||
instance, to create a container that has <command>sshd</command> running,
|
||
with the given public key for <literal>root</literal>:
|
||
<screen>
|
||
# nixos-container create foo --config '
|
||
<xref linkend="opt-services.openssh.enable"/> = true;
|
||
<link linkend="opt-users.users._name__.openssh.authorizedKeys.keys">users.users.root.openssh.authorizedKeys.keys</link> = ["ssh-dss AAAAB3N…"];
|
||
'
|
||
</screen>
|
||
By default the next free address in the <literal>10.233.0.0/16</literal> subnet will be chosen
|
||
as container IP. This behavior can be altered by setting <literal>--host-address</literal> and
|
||
<literal>--local-address</literal>:
|
||
<screen>
|
||
# nixos-container create test --config-file test-container.nix \
|
||
--local-address 10.235.1.2 --host-address 10.235.1.1
|
||
</screen>
|
||
</para>
|
||
|
||
<para>
|
||
Creating a container does not start it. To start the container, run:
|
||
<screen>
|
||
# nixos-container start foo
|
||
</screen>
|
||
This command will return as soon as the container has booted and has reached
|
||
<literal>multi-user.target</literal>. On the host, the container runs within
|
||
a systemd unit called
|
||
<literal>container@<replaceable>container-name</replaceable>.service</literal>.
|
||
Thus, if something went wrong, you can get status info using
|
||
<command>systemctl</command>:
|
||
<screen>
|
||
# systemctl status container@foo
|
||
</screen>
|
||
</para>
|
||
|
||
<para>
|
||
If the container has started successfully, you can log in as root using the
|
||
<command>root-login</command> operation:
|
||
<screen>
|
||
# nixos-container root-login foo
|
||
[root@foo:~]#
|
||
</screen>
|
||
Note that only root on the host can do this (since there is no
|
||
authentication). You can also get a regular login prompt using the
|
||
<command>login</command> operation, which is available to all users on the
|
||
host:
|
||
<screen>
|
||
# nixos-container login foo
|
||
foo login: alice
|
||
Password: ***
|
||
</screen>
|
||
With <command>nixos-container run</command>, you can execute arbitrary
|
||
commands in the container:
|
||
<screen>
|
||
# nixos-container run foo -- uname -a
|
||
Linux foo 3.4.82 #1-NixOS SMP Thu Mar 20 14:44:05 UTC 2014 x86_64 GNU/Linux
|
||
</screen>
|
||
</para>
|
||
|
||
<para>
|
||
There are several ways to change the configuration of the container. First,
|
||
on the host, you can edit
|
||
<literal>/var/lib/container/<replaceable>name</replaceable>/etc/nixos/configuration.nix</literal>,
|
||
and run
|
||
<screen>
|
||
# nixos-container update foo
|
||
</screen>
|
||
This will build and activate the new configuration. You can also specify a
|
||
new configuration on the command line:
|
||
<screen>
|
||
# nixos-container update foo --config '
|
||
<xref linkend="opt-services.httpd.enable"/> = true;
|
||
<xref linkend="opt-services.httpd.adminAddr"/> = "foo@example.org";
|
||
<xref linkend="opt-networking.firewall.allowedTCPPorts"/> = [ 80 ];
|
||
'
|
||
|
||
# curl http://$(nixos-container show-ip foo)/
|
||
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 3.2 Final//EN">…
|
||
</screen>
|
||
However, note that this will overwrite the container’s
|
||
<filename>/etc/nixos/configuration.nix</filename>.
|
||
</para>
|
||
|
||
<para>
|
||
Alternatively, you can change the configuration from within the container
|
||
itself by running <command>nixos-rebuild switch</command> inside the
|
||
container. Note that the container by default does not have a copy of the
|
||
NixOS channel, so you should run <command>nix-channel --update</command>
|
||
first.
|
||
</para>
|
||
|
||
<para>
|
||
Containers can be stopped and started using <literal>nixos-container
|
||
stop</literal> and <literal>nixos-container start</literal>, respectively, or
|
||
by using <command>systemctl</command> on the container’s service unit. To
|
||
destroy a container, including its file system, do
|
||
<screen>
|
||
# nixos-container destroy foo
|
||
</screen>
|
||
</para>
|
||
</section>
|