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Registries

Helm 3 supports OCI for package distribution. Chart packages are able to be stored and shared across OCI-based registries.

Enabling OCI Support

Currently OCI support is considered experimental.

In order to use the commands described below, please set HELM_EXPERIMENTAL_OCI in the enironment:

export HELM_EXPERIMENTAL_OCI=1

Running a registry

Starting a registry for test purposes is trivial. As long as you have Docker installed, run the following command:

docker run -dp 5000:5000 --restart=always --name registry registry

This will start a registry server at localhost:5000.

Use docker logs -f registry to see the logs and docker rm -f registry to stop.

If you wish to persist storage, you can add -v $(pwd)/registry:/var/lib/registry to the command above.

For more configuration options, please see the docs.

Auth

If you wish to enable auth on the registry, you can do the following-

First, create file auth.htpasswd with username and password combo:

htpasswd -cB -b auth.htpasswd myuser mypass

Then, start the server, mounting that file and setting the REGISTRY_AUTH env var:

docker run -dp 5000:5000 --restart=always --name registry \
  -v $(pwd)/auth.htpasswd:/etc/docker/registry/auth.htpasswd \
  -e REGISTRY_AUTH="{htpasswd: {realm: localhost, path: /etc/docker/registry/auth.htpasswd}}" \
  registry

Commands for working with registries

Commands are available under both helm registry and helm chart that allow you to work with registries and local cache.

The registry subcommand

login

login to a registry (with manual password entry)

$ helm registry login -u myuser localhost:5000
Password:
Login succeeded

logout

logout from a registry

$ helm registry logout localhost:5000
Logout succeeded

The chart subcommand

save

save a chart directory to local cache

$ helm chart save mychart/ localhost:5000/myrepo/mychart:2.7.0
ref:     localhost:5000/myrepo/mychart:2.7.0
digest:  1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617
size:    2.4 KiB
name:    mychart
version: 0.1.0
2.7.0: saved

list

list all saved charts

$ helm chart list
REF                                                     NAME                    VERSION DIGEST  SIZE            CREATED
localhost:5000/myrepo/mychart:2.7.0                     mychart                 2.7.0   84059d7 454 B           27 seconds
localhost:5000/stable/acs-engine-autoscaler:2.2.2       acs-engine-autoscaler   2.2.2   d8d6762 4.3 KiB         2 hours
localhost:5000/stable/aerospike:0.2.1                   aerospike               0.2.1   4aff638 3.7 KiB         2 hours
localhost:5000/stable/airflow:0.13.0                    airflow                 0.13.0  c46cc43 28.1 KiB        2 hours
localhost:5000/stable/anchore-engine:0.10.0             anchore-engine          0.10.0  3f3dcd7 34.3 KiB        2 hours
...

export

export a chart to directory

$ helm chart export localhost:5000/myrepo/mychart:2.7.0
ref:     localhost:5000/myrepo/mychart:2.7.0
digest:  1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617
size:    2.4 KiB
name:    mychart
version: 0.1.0
Exported chart to mychart/

push

push a chart to remote

$ helm chart push localhost:5000/myrepo/mychart:2.7.0
The push refers to repository [localhost:5000/myrepo/mychart]
ref:     localhost:5000/myrepo/mychart:2.7.0
digest:  1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617
size:    2.4 KiB
name:    mychart
version: 0.1.0
2.7.0: pushed to remote (1 layer, 2.4 KiB total)

remove

remove a chart from cache

$ helm chart remove localhost:5000/myrepo/mychart:2.7.0
2.7.0: removed

pull

pull a chart from remote

$ helm chart pull localhost:5000/myrepo/mychart:2.7.0
2.7.0: Pulling from localhost:5000/myrepo/mychart
ref:     localhost:5000/myrepo/mychart:2.7.0
digest:  1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617
size:    2.4 KiB
name:    mychart
version: 0.1.0
Status: Downloaded newer chart for localhost:5000/myrepo/mychart:2.7.0

Where are my charts?

Charts stored using the commands above will be cached on the filesystem.

The OCI Image Layout Specification is adhered to strictly for filesystem layout, for example:

$ tree ~/Library/Caches/helm/
/Users/myuser/Library/Caches/helm/
└── registry
    ├── cache
    │   ├── blobs
    │   │   └── sha256
    │   │       ├── 1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617
    │   │       ├── 31fb454efb3c69fafe53672598006790122269a1b3b458607dbe106aba7059ef
    │   │       └── 8ec7c0f2f6860037c19b54c3cfbab48d9b4b21b485a93d87b64690fdb68c2111
    │   ├── index.json
    │   ├── ingest
    │   └── oci-layout
    └── config.json

Example index.json, which contains refs to all Helm chart manifests:

$ cat ~/Library/Caches/helm/registry/cache/index.json  | jq
{
  "schemaVersion": 2,
  "manifests": [
    {
      "mediaType": "application/vnd.oci.image.manifest.v1+json",
      "digest": "sha256:31fb454efb3c69fafe53672598006790122269a1b3b458607dbe106aba7059ef",
      "size": 354,
      "annotations": {
        "org.opencontainers.image.ref.name": "localhost:5000/myrepo/mychart:2.7.0"
      }
    }
  ]
}

Example Helm chart manifest (note the mediaType fields):

$ cat ~/Library/Caches/helm/registry/cache/blobs/sha256/31fb454efb3c69fafe53672598006790122269a1b3b458607dbe106aba7059ef | jq
{
  "schemaVersion": 2,
  "config": {
    "mediaType": "application/vnd.cncf.helm.config.v1+json",
    "digest": "sha256:8ec7c0f2f6860037c19b54c3cfbab48d9b4b21b485a93d87b64690fdb68c2111",
    "size": 117
  },
  "layers": [
    {
      "mediaType": "application/vnd.cncf.helm.chart.content.layer.v1+tar",
      "digest": "sha256:1b251d38cfe948dfc0a5745b7af5ca574ecb61e52aed10b19039db39af6e1617",
      "size": 2487
    }
  ]
}

Migrating from chart repos

Migrating from classic chart repositories (index.yaml-based repos) is as simple as a helm fetch (Helm 2 CLI), helm chart save, helm chart push.