61 lines
2.2 KiB
XML
61 lines
2.2 KiB
XML
<section 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-declarative-containers">
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<title>Declarative Container Specification</title>
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<para>You can also specify containers and their configuration in the
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host’s <filename>configuration.nix</filename>. For example, the
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following specifies that there shall be a container named
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<literal>database</literal> running PostgreSQL:
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<programlisting>
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containers.database =
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{ config =
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{ config, pkgs, ... }:
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{ services.postgresql.enable = true;
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services.postgresql.package = pkgs.postgresql92;
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};
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};
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</programlisting>
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If you run <literal>nixos-rebuild switch</literal>, the container will
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be built. If the container was already running, it will be
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updated in place, without rebooting. The container can be configured to
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start automatically by setting <literal>containers.database.autoStart = true</literal>
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in its configuration.</para>
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<para>By default, declarative containers share the network namespace
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of the host, meaning that they can listen on (privileged)
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ports. However, they cannot change the network configuration. You can
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give a container its own network as follows:
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<programlisting>
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containers.database =
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{ privateNetwork = true;
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hostAddress = "192.168.100.10";
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localAddress = "192.168.100.11";
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};
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</programlisting>
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This gives the container a private virtual Ethernet interface with IP
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address <literal>192.168.100.11</literal>, which is hooked up to a
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virtual Ethernet interface on the host with IP address
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<literal>192.168.100.10</literal>. (See the next section for details
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on container networking.)</para>
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<para>To disable the container, just remove it from
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<filename>configuration.nix</filename> and run <literal>nixos-rebuild
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switch</literal>. Note that this will not delete the root directory of
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the container in <literal>/var/lib/containers</literal>. Containers can be
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destroyed using the imperative method: <literal>nixos-container destroy
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foo</literal>.</para>
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<para>Declarative containers can be started and stopped using the
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corresponding systemd service, e.g. <literal>systemctl start
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container@database</literal>.</para>
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</section>
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