---
title: 'Docker Read-Through Cache'
description: 'Serve repeated Docker image pulls from a cache close to your Nx Agents instead of the upstream registry.'
keywords:
  [
    docker,
    read-through cache,
    registry mirror,
    pull-through,
    nx agents,
    nx cloud,
    add-on,
  ]
sidebar:
  label: Docker read-through cache
  order: 22
  badge: new!
filter: 'type:Features'
---

The Docker read-through cache puts a registry mirror close to your [Nx Agents](/docs/features/ci-features/distribute-task-execution).
The first time an image is pulled, it is fetched from the upstream registry (for example Docker Hub)
and stored in the cache. Repeated pulls of the same image are then served from the cache instead of
the upstream registry, cutting image download time and reducing dependence on external registries.

It also protects your organization from Docker registry outages.

## How to enable it

{% aside type="note" title="Requires a dedicated compute cluster" %}
The Docker read-through cache is an Nx Cloud add-on that runs on a
[dedicated compute cluster](/docs/features/ci-features/dedicated-compute-cluster). Request the
cluster, then enable this add-on under **Settings > Add-ons**.
{% /aside %}

You can enable Docker read-through cache through your organization settings:

1. Open **Settings > Add-ons** for your organization.
2. Under **Dedicated compute cluster** card, find **Docker read-through cache** and click **Request add-on** and confirm.

Once enabled, it works automatically. You don't change your Dockerfiles, `docker pull` commands, or
image references. Repeated image pulls are served from the cache instead of the upstream registry.