path: root/doc/manual/packages/s3-substituter.xml

<?xml version="1.0" encoding="utf-8"?>
<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="ssec-s3-substituter">

<title>Serving a Nix store via AWS S3 or S3-compatible Service</title>

<para>Nix has built-in support for storing and fetching store paths
from Amazon S3 and S3 compatible services. This uses the same
<emphasis>binary</emphasis> cache mechanism that Nix usually uses to
fetch prebuilt binaries from <uri>cache.nixos.org</uri>.</para>

<para>In this example we will use the bucket named
<literal>example-bucket</literal>.</para>

<section xml:id="ssec-s3-substituter-anonymous-reads">
  <title>Anonymous Reads to your S3-compatible binary cache</title>

  <para>If your binary cache is publicly accessible and does not
  require authentication, the simplest and easiest way to use Nix with
  your S3 compatible binary cache is to use the HTTP URL for that
  cache.</para>

  <para>For AWS S3 the binary cache URL for example bucket will be
  exactly <uri>https://example-bucket.s3.amazonaws.com</uri>. For S3
  compatible binary caches ago have to consult your software's
  documentation.</para>

  <para>Your bucket will need the following bucket policy:</para>

  <programlisting>
<![CDATA[
{
  "Id": "DirectReads",
  "Version": "2012-10-17",
  "Statement": [
    {
      "Sid": "AlowDirectReads",
      "Action": [
        "s3:GetObject"
      ],
      "Effect": "Allow",
      "Resource": "arn:aws:s3:::example-bucket/*",
      "Principal": "*"
    }
  ]
}
]]>
</programlisting>
</section>

<section xml:id="ssec-s3-substituter-authenticated-reads">
  <title>Authenticated Reads to your S3 binary cache</title>

  <para>For AWS S3 the binary cache URL for example bucket will be
  exactly <uri>s3://example-bucket</uri>.</para>

  <para>Nix will use the <link
  xlink:href="https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/credentials.html#credentials-default.">default
  credential provider chain</link> for authenticating requests to
  Amazon S3.</para>

  <para>Nix supports authenticated writes to S3 compatible binary
  caches but only supports Authenticated reads from Amazon S3.
  Additionally, the following limitations are in place for
  authenticated reads:</para>

  <itemizedlist>
    <listitem><para>The bucket must actually be hosted by Amazon S3 and
    <emphasis>not</emphasis> an S3 compatible
    service.</para></listitem>

    <listitem><para>The bucket must be within the
    <literal>us-east-1</literal> region.</para></listitem>

    <listitem><para>The Amazon credentials, if stored in a credential
    profile, must be stored in the <literal>default</literal>
    profile.</para></listitem>
  </itemizedlist>

  <para>Your bucket will need a bucket policy allowing the desired
  users to perform the <literal>s3:GetObject</literal> action on all
  objects in the bucket.</para>
</section>


<section xml:id="ssec-s3-substituter-authenticated-writes">
  <title>Authenticated Writes to your S3-compatible binary cache</title>

  <para>Nix support fully supports writing to Amazon S3 and S3
  compatible buckets. The binary cache URL for our example bucket will
  be <uri>s3://example-bucket</uri>.</para>

  <para>Nix will use the <link
  xlink:href="https://docs.aws.amazon.com/sdk-for-java/v1/developer-guide/credentials.html#credentials-default.">default
  credential provider chain</link> for authenticating requests to
  Amazon S3.</para>

  <para>The following options can be specified as URL parameters to
  the S3 URL:</para>
  <variablelist>
    <varlistentry><term><literal>profile</literal></term>
    <listitem>
      <para>
        The name of the AWS configuration profile to use. By default
        Nix will use the <literal>default</literal> profile.
      </para>
    </listitem>
    </varlistentry>

    <varlistentry><term><literal>region</literal></term>
    <listitem>
      <para>
        The region of the S3 bucket. <literal>us–east-1</literal> by
        default.
      </para>
    </listitem>
    </varlistentry>
  </variablelist>

  <example><title>Uploading with non-default credential profile for Amazon S3</title>
    <para><command>nix copy --to ssh://machine nixpkgs.hello s3://example-bucket?profile=cache-upload</command></para>
  </example>

  <para>The user writing to the bucket will need to perform the
  following actions against the bucket:</para>

  <itemizedlist>
    <listitem><para><literal>s3:ListBucket</literal></para></listitem>
    <listitem><para><literal>s3:GetBucketLocation</literal></para></listitem>
    <listitem><para><literal>s3:ListObjects</literal></para></listitem>
    <listitem><para><literal>s3:GetObject</literal></para></listitem>
    <listitem><para><literal>s3:PutObject</literal></para></listitem>
    <listitem><para><literal>s3:ListBucketMultipartUploads</literal></para></listitem>
    <listitem><para><literal>s3:CreateMultipartUpload</literal></para></listitem>
    <listitem><para><literal>s3:ListMultipartUploadParts</literal></para></listitem>
    <listitem><para><literal>s3:AbortMultipartUpload</literal></para></listitem>
  </itemizedlist>
</section>
</section>