zot/README.md

# zot [![build-test](https://github.com/project-zot/zot/actions/workflows/ci-cd.yml/badge.svg?branch=main)](https://github.com/project-zot/zot/actions/workflows/ci-cd.yml) [![codecov.io](http://codecov.io/github/project-zot/zot/coverage.svg?branch=main)](http://codecov.io/github/project-zot/zot?branch=main) [![Conformance Results](https://github.com/project-zot/zot/workflows/conformance/badge.svg)](https://github.com/project-zot/zot/actions?query=workflow%3Aconformance) [![CodeQL](https://github.com/project-zot/zot/workflows/CodeQL/badge.svg)](https://github.com/project-zot/zot/actions?query=workflow%3ACodeQL) [![CII Best Practices](https://bestpractices.coreinfrastructure.org/projects/5425/badge)](https://bestpractices.coreinfrastructure.org/projects/5425)

**zot**: a production-ready vendor-neutral OCI image registry - images stored in [OCI image format](https://github.com/opencontainers/image-spec), [distribution specification](https://github.com/opencontainers/distribution-spec) on-the-wire, that's it!

https://zotregistry.io

[```docker pull ghcr.io/project-zot/zot-linux-amd64:latest```](https://github.com/project-zot/zot/pkgs/container/zot)

[```docker run -p 5000:5000 ghcr.io/project-zot/zot-linux-amd64:latest```](https://github.com/project-zot/zot/pkgs/container/zot)

**Check the [package repository](https://github.com/orgs/project-zot/packages?repo_name=zot) for your os/arch**

The following document refers on the **core dist-spec**, see also the [zot-specific extensions spec](pkg/extensions/README.md)


## [**Why zot?**](COMPARISON.md)

## What's new?
* Support content range for pull requests
* Selectively add extensions on top of minimal build
* Supports container image signatures - [cosign](https://github.com/sigstore/cosign) and [notation](https://github.com/notaryproject/notation)
* Multi-arch support
* Clustering support
* Image linting support

## [Demos](demos/README.md)

# Features
* Conforms to [OCI distribution spec](https://github.com/opencontainers/distribution-spec) APIs
* Clear separation between core dist-spec and zot-specific extensions
  * ```make binary-minimal``` builds a dist-spec-only zot
  * ```make binary``` builds a zot with all extensions enabled 

  **Check [released binaries](https://github.com/project-zot/zot/releases) for your os/arch**

* Uses [OCI image layout](https://github.com/opencontainers/image-spec/blob/master/image-layout.md) for image storage
  * Can serve any OCI image layout as a registry 
* Supports container image signatures - [cosign](https://github.com/sigstore/cosign) and [notation](https://github.com/notaryproject/notation)
* Supports [helm charts](https://helm.sh/docs/topics/registries/)
* Behavior controlled via [configuration](./examples/README.md)
* Supports multi-arch
    | OS | Arch | Use Case |
    | --- | --- | --- |
    | linux | amd64 | Intel-based Linux platforms |
    | linux | arm64 | ARM servers and Raspberry PI4 |
    | darwin | amd64 | Intel-based Macs |
    | darwin | arm64 | ARM-based Macs |
* Supports image deletion by tag
* Currently suitable for on-prem deployments (e.g. colocated with Kubernetes)
* Compatible with ecosystem tools such as [skopeo](#skopeo) and [cri-o](#cri-o)
* [Vulnerability scanning of images](#Scanning-images-for-known-vulnerabilities)
* TLS support
* Authentication via:
  * TLS mutual authentication
  * HTTP *Basic* (local _htpasswd_ and LDAP)
  * HTTP *Bearer* token
* Supports Identity-Based Access Control
* Supports live modifications on the config file while zot is running (Authorization config only)
* Doesn't require _root_ privileges
* Storage optimizations:
  * Automatic garbage collection of orphaned blobs
  * Layer deduplication using hard links when content is identical
* Serve [multiple storage paths (and backends)](./examples/config-multiple.json) using a single zot server
* Pull and synchronize from other dist-spec conformant registries [sync](#sync)
* Supports ratelimiting including per HTTP method
* [Metrics](#metrics) with Prometheus
* Swagger based documentation
* Single binary for _all_ the above features
* [zli](https://github.com/project-zot/zot/tree/main/cmd/zli): [command-line client support](#cli)
* Also, [zb](https://github.com/project-zot/zot/tree/main/cmd/zb): [a benchmarking tool](#benchmarking) for dist-spec conformant registries
* Released under Apache 2.0 License
  * Using a node exporter in case of dist-spec-only zot
* ```go get -u github.com/project-zot/zot/cmd/zot```

# Presentations

* [OCI Weekly Discussion - Oct 2, 2019](https://github.com/opencontainers/.github/blob/master/meeting-notes/oci-weekly-notes-2019-mar-2020-mar.md#october-2-2019)

# Build and install binary (using host's toolchain)

```
go get -u github.com/project-zot/zot/cmd/zot
```

# Full CI/CD Build

* Build inside a container (preferred)

```
make binary-container
```

* Alternatively, build inside a container using [stacker](https://github.com/project-stacker/stacker) (preferred)

```
make binary-stacker
```

* Build using host's toolchain

```
make
```

* Build zot with specified extensions
```
make binary EXTENSIONS=extension1,extension2,extension3
# e.g. make binary EXTENSIONS=sync,search,metrics,scrub
```

Build artifacts are in bin/

# Serving

```
bin/zot serve _config-file_
```

Examples of config files are available in [examples/](examples/) dir.

# Container Image

The [Dockerfile](./Dockerfile) in this repo can be used to build a container image
that runs _zot_.

To build the image with ref `zot:latest`:

```
make image
```

Then run the image with your preferred container runtime:

```
# with podman
podman run --rm -it -p 5000:5000 -v $(pwd)/registry:/var/lib/registry zot:latest

# with docker
docker run --rm -it -p 5000:5000 -v $(pwd)/registry:/var/lib/registry zot:latest
```

This will run a registry at http://localhost:5000, storing content at `./registry` 
(bind mounted to `/var/lib/registry` in the container). By default, auth is disabled.

If you wish use custom configuration settings, you can override
the YAML config file located at `/etc/zot/config.yml`:

```
# Example: using a local file "custom-config.yml" that
# listens on port 8080 and uses /tmp/zot for storage root
podman run --rm -p 8080:8080 \
  -v $(pwd)/custom-config.yml:/etc/zot/config.yml \
  -v $(pwd)/registry:/tmp/zot \
  zot:latest
```

# CLI

## Building `zli`

You can interact with the zot registry server using the `zli` binary.

```console
$ make cli
```

will produce `bin/zli` binary.

## Adding a zot server URL

To add a zot server URL with an alias "remote-zot":

```console
$ zli config add remote-zot https://server-example:8080
```

List all configured URLs with their aliases:
```console
$ zli config -l
remote-zot https://server-example:8080
local      http://localhost:8080
```

## Listing images
You can list all images from a server by using its alias specified [in this step](#adding-a-zot-server-url):

```console
$ zli images remote-zot
IMAGE NAME                        TAG                       DIGEST    SIZE
postgres                          9.6.18-alpine             ef27f3e1  14.4MB
postgres                          9.5-alpine                264450a7  14.4MB
busybox                           latest                    414aeb86  707.8KB
```

Or filter the list by an image name:

```console
$ zli images remote-zot -n busybox
IMAGE NAME                        TAG                       DIGEST    SIZE
busybox                           latest                    414aeb86  707.8KB
```
## Scanning images for known vulnerabilities

You can fetch CVE (Common Vulnerabilities and Exposures) info for images hosted on zot

- Get all images affected by a CVE

```console
$ zli cve remote-zot -i CVE-2017-9935
IMAGE NAME                        TAG                       DIGEST    SIZE
c3/openjdk-dev                    commit-5be4d92            ac3762e2  335MB
```

- Get all CVEs for an image

```console
$ zli cve remote-zot -I c3/openjdk-dev:0.3.19
ID                SEVERITY  TITLE
CVE-2015-8540     LOW       libpng: underflow read in png_check_keyword()
CVE-2017-16826    LOW       binutils: Invalid memory access in the coff_s...
```

- Get detailed json output

```console
$ zli cve remote-zot -I c3/openjdk-dev:0.3.19 -o json
{
  "Tag": "0.3.19",
  "CVEList": [
    {
      "Id": "CVE-2019-17006",
      "Severity": "MEDIUM",
      "Title": "nss: Check length of inputs for cryptographic primitives",
      "Description": "A vulnerability was discovered in nss where input text length was not checked when using certain cryptographic primitives. This could lead to a heap-buffer overflow resulting in a crash and data leak. The highest threat is to confidentiality and integrity of data as well as system availability.",
      "PackageList": [
        {
          "Name": "nss",
          "InstalledVersion": "3.44.0-7.el7_7",
          "FixedVersion": "Not Specified"
        },
        {
          "Name": "nss-sysinit",
          "InstalledVersion": "3.44.0-7.el7_7",
          "FixedVersion": "Not Specified"
        },
        {
          "Name": "nss-tools",
          "InstalledVersion": "3.44.0-7.el7_7",
          "FixedVersion": "Not Specified"
        }
      ]
    },
```

- Get all images in a specific repo affected by a CVE

```console
$ zli cve remote-zot -I c3/openjdk-dev -i CVE-2017-9935
IMAGE NAME                        TAG                       DIGEST    SIZE
c3/openjdk-dev                    commit-2674e8a            71046748  338MB
c3/openjdk-dev                    commit-bd5cc94            0ab7fc76  
```

- Get all images of a specific repo where a CVE is fixed

```console
$ zli cve remote-zot -I c3/openjdk-dev -i CVE-2017-9935 --fixed
IMAGE NAME                        TAG                       DIGEST    SIZE
c3/openjdk-dev                    commit-2674e8a-squashfs   b545b8ba  321MB
c3/openjdk-dev                    commit-d5024ec-squashfs   cd45f8cf  321MB
```

# Sync (pull-based mirroring)
Periodically pull and synchronize images between zot registries.
The synchronization is achieved by copying all the images found at source to destination.
To use it see [sync-config](examples/config-sync.json)
Supports:
  - TLS verification
  - Prefix filtering (can contain multiple repos, eg repo1/repoX/repoZ)
  - Tags regex filtering
  - Tags semver compliance filtering (the 'v' prefix is optional)
  - BASIC auth
  - Image signatures

# Benchmarking

You can benchmark a zot registry or any other dist-spec conformant registry with `zb`.

## Building `zb``

```console
$ make bench
```

will produce `bin/zb` binary.

## Running `zb`

```console
$ zb -c 10 -n 1000 http://localhost:8080

Registry URL: http://localhost:8080

Concurrency Level: 2
Total requests:    100
Working dir:

============
Test name:            Get Catalog
Time taken for tests: 45.397205ms
Complete requests:    100
Failed requests:      0
Requests per second:  2202.7788

2xx responses: 100

min: 402.259µs
max: 3.295887ms
p50: 855.045µs
p75: 971.709µs
p90: 1.127389ms
p99: 3.295887ms

============
Test name:            Push Monolith 1MB
Time taken for tests: 952.336383ms
Complete requests:    100
Failed requests:      0
Requests per second:  105.00491

2xx responses: 100

min: 11.125673ms
max: 26.375356ms
p50: 18.917253ms
p75: 21.753441ms
p90: 24.02137ms
p99: 26.375356ms

...
```


# Ecosystem


## skopeo

[skopeo](https://github.com/containers/skopeo) is a tool to work with remote
image repositories.

* Pull Images

```
skopeo copy docker://<zot-server:port>/repo:tag docker://<another-server:port>/repo:tag
```

* Push Images

```
skopeo copy --format=oci docker://<another-server:port>/repo:tag docker://<zot-server:port>/repo:tag
```

## cri-o

[cri-o](https://github.com/cri-o/cri-o) is a OCI-based Kubernetes container
runtime interface.

Works with "docker://" transport which is the default.

# Metrics

Can be used for both dist-spec-only zot & the zot with all extensions enabled

## Node Exporter
The dist-spec-only zot exposes internal metrics into a Prometheus format through a node exporter.
The configuration of node exporter contains connection details for the zot server it is intend to scrape metrics from. See a [configuration example](./examples/metrics/exporter/config-minimal.json). The metrics are automatically enabled in the zot server on first scrape from the Node Exporter (no extra configuration option is needed). Similarly, the metrics are automatically disabled when Node Exporter did not perform any scrapings in a while.

```
bin/zxp config _config-file_
```

## Enable Metrics
In the zot with all extensions case see [configuration example](./examples/config-metrics.json) for enabling metrics

## Image linting

# Mandatory Annotations
When pushing an image, if the mandatory annotations option is enabled, linter will verify if the mandatory annotations list present in the config is also found in the manifest's annotations list. If there are any missing annotations, the push will not take place.

## Clustering

zot supports clustering by using multiple stateless zot with shared s3 storage and a haproxy (with sticky session) in front of them.

- haproxy [configuration example](./examples/cluster/haproxy.cfg)
- zot s3 [configuration example](./examples/config-s3.json)

# Contributing

We encourage and support an active, healthy community of contributors.

* Details are in the [code of conduct](CODE_OF_CONDUCT.md)
* Details to get started on code development are in
[contributing](CONTRIBUTING.md) document.