docker registry #101


Service for hosting docker images


This charm provides storage and distribution of docker images. See for details.


The registry is deployed as a stand alone application and supports integration
with clients that implement the docker-registry interface.

Standalone Registry

For testing purposes, a simple, insecure registry can be deployed with:

juju deploy ~containers/docker-registry

Secure Registry with TLS

This charm supports TLS via the tls-certificates relation. This can
be enabled by deploying and relating to a TLS provider, such as easyrsa:

juju deploy ~containers/docker-registry
juju deploy ~containers/easyrsa

juju add-relation easyrsa docker-registry

This charm also supports configuration-based TLS, which does not require a
relation to a TLS provider. Instead, transfer required files and configure
this charm as follows:

juju scp /my/local/ca.pem docker-registry/0:/home/ubuntu/ca.pem
juju scp /my/local/cert.crt docker-registry/0:/home/ubuntu/cert.crt
juju scp /my/local/cert.key docker-registry/0:/home/ubuntu/cert.key

juju config docker-registry \
  tls-ca-path=/home/ubuntu/ca.pem \
  tls-cert-path=/home/ubuntu/cert.crt \

Finally, custom TLS data may be provided as base64-encoded config options to
the charm. The configured tls-*-blob data will be written to corresponding
configured tls-*-path files:

juju config docker-registry \
  tls-ca-blob=$(base64 /path/to/ca) \
  tls-cert-blob=$(base64 /path/to/cert) \
  tls-key-blob=$(base64 /path/to/key)

Proxied Registry

This charm supports an http proxy relation that allows operators to
control how the registry is exposed on the network. This is achieved by
relating to a proxy provider, such as haproxy.

Note: SSL pass-thru is not supported between docker-registry and haproxy.
Any registry SSL configuration must be removed before creating the proxy
relation. If SSL is desired in a proxied environment, the administrator must
ensure certificates used by the proxy are configured on the appropriate target

A proxied registry environment can be deployed as follows:

juju deploy ~containers/docker-registry
juju deploy haproxy

juju add-relation haproxy docker-registry

When multiple docker-registry units are deployed, the proxy will be
configured with one unit chosen as the primary proxied service with remaining
units configured as backups. This provides a highly available deployment that
will fail over to a backup if the primary service becomes unavailable.

Note: HA deployments require the proxy to be in active-passive peering
mode, which is the default for haproxy.

Nagios Monitoring

This charm supports monitoring with nagios:

juju deploy ~containers/docker-registry
juju deploy nrpe --series bionic

juju relate docker-registry nrpe

Kubernetes Integration

See the Private Docker Registry documentation for details on
integrating this charm with Kubernetes.


Hosting Images

To make an image available in the deployed registry, it must be tagged and
pushed. This charm provides the push action to do this:

juju run-action --wait docker-registry/0 push \
  image=<image> pull=<True|False> tag=<optional-tag-name>

This action will always tag and push a local image to the registry. By
specifying pull=True (the default), the action will first pull the
given image and subsequently tag/push it.

The default image tag is 'net_loc/name:version', where 'net_loc' is the
http-host config option or http[s]://[private-ip]:[port] if config is not
set. The image tag can be overriden by specifying the tag action parameter.


The registry is configured to start automatically with the dockerd system
service. It can also be started or stopped with charm actions as follows:

juju run-action --wait docker-registry/0 stop
juju run-action --wait docker-registry/0 start



This charm supports basic (htpasswd) as well as token-based authentication.
Configure either method as follows:

juju config docker-registry \
  auth-basic-user='admin' \

juju config docker-registry \
  auth-token-issuer='' \
  auth-token-realm='myorg' \
  auth-token-root-certs='$(base64 /path/to/file)' \

Read-Only Mode

The registry can be switched to read-only mode by setting
the storage-read-only config option to true:

juju config docker-registry storage-read-only=true

This may be useful when performing maintenance or deploying an environment
with complex authentication requirements.

As an example, consider a scenario that requires unauthenticated pull
and authenticated push access to the registry. This can be achieved by
deploying this charm twice with the same storage backend (for example,
a Swift object storage cluster):

juju deploy docker-registry public --config <storage-swift-opts>
juju deploy docker-registry private --config <storage-swift-opts>

Configure the unauthenticated public registry to be read-only, and enable
authentication for the private registry:

juju config public storage-read-only=true
juju config private <auth-opts>

With a common storage backend and appropriate configuration, unauthenticated
public users have a read-only view of the images pushed by authenticated
private users.

Swift Storage

The charm supports Swift configuration options that can be used to store
images in a Swift backend:

juju config docker-registry \
  storage-swift-authurl=<url> \
  storage-swift-container=<container> \
  storage-swift-password=<pass> \
  storage-swift-region=<region> \
  storage-swift-tenant=<tenant> \

Note: If any of the swift config options are set, they must all be set.

Also note that if the swift container is empty, requests to the registry may
return 503 errors like the following:

{"errors":[{"code":"UNAVAILABLE","message":"service unavailable","detail":"health check failed: please see /debug/health"}]}

Per, upload an empty file
called "files" at the root of the container to workaround the issue.


The docker-registry charm is free and open source software created by the
~containers team at Canonical.


(string) The username to use to access swift.
(string) The URL of the keystone used to authenticate to swift.
(string) Path to the TLS certificate.
(boolean) Toggle installation from Ubuntu archive vs the Docker PPA (DEPRECATED; please use docker_runtime instead).
(string) URL to use for HTTP_PROXY to be used by Docker. Useful in egress-filtered environments where a proxy is the only option for accessing the registry to pull images.
(string) Name of the registry container.
(string) The name on the certificate that authentication tokens must me signed by.
(string) Extra options to pass to the Docker daemon. e.g. --insecure-registry.
(string) List of signing keys for install_sources package sources, per charmhelpers standard format (a yaml list of strings encoded as a string). The keys should be the full ASCII armoured GPG public keys. While GPG key ids are also supported and looked up on a keyserver, operators should be aware that this mechanism is insecure. null can be used if a standard package signing key is used that will already be installed on the machine, and for PPA sources where the package signing key is securely retrieved from Launchpad.
(string) Custom Docker repository package name.
(string) Registry image.
(string) The tenant containing the swift service.
(string) Comma-separated list of destinations (either domain names or IP addresses) which should be accessed directly, rather than through the proxy defined in http_proxy or https_proxy. Must be less than 2023 characters long.
(string) Password for basic (htpasswd) authentication. Set this to something other than an empty string to configure basic auth for the registry.
(string) Base64 encoded TLS certificate private key (overwrites tls-key-path file).
(string) URL to use for HTTPS_PROXY to be used by Docker. Useful in egress-filtered environments where a proxy is the only option for accessing the registry to pull images.
(string) Path the the TLS certificate private key.
(boolean) Controls the storage maintenance option "readonly".
(boolean) Enable GRUB cgroup overrides cgroup_enable=memory swapaccount=1. WARNING changing this option will reboot the host - use with caution on production services.
(int) The external port on which the docker registry listens.
(string) Custom Docker repository, given in deb format. Use `{ARCH}` to determine architecture at runtime. Use `{CODE}` to set release codename. E.g. `deb [arch={ARCH}] {CODE} stable`.
(string) A comma-separated list of nagios servicegroups. If left empty, the nagios_context will be used as the servicegroup
(string) The external URL where the docker registry is hosted. This URL will be prepended to all locations generated by the docker registry to ensure that those URLs are reachable by the client. For example "". Any path component must include a trailing "/". If this is not configured then the docker registry will derive its location from the incoming requests.
(string) Path to the TLS CA certificate.
(string) The location from which clients should fetch authentication tokens.
(string) The password to use to access swift.
(string) The status of service-affecting packages will be set to this value in the dpkg database. Valid values are "install" and "hold".
(string) Username for basic (htpasswd) authentication.
(string) The region containing the swift service.
(string) The name of the swift container that will hold the images.
(string) The pinned version of docker-ce package installed with nvidia-docker.
(string) Base64 encoded TLS CA certificate (overwrites tls-cert-path file).
(string) The cuda-repo package version to install.
(string) Used by the nrpe subordinate charms. A string that will be prepended to instance name to set the host name in nagios. So for instance the hostname would be something like: juju-myservice-0 If you're running multiple environments with the same services in them this allows you to differentiate between them.
(string) Logging output level ('error', 'warn', 'info', or 'debug').
(string) Base64 encoded TLS certificate (overwrites tls-cert-path file).
(string) The root certificate bundle (base64 encoded) for the authentication tokens.
(string) Docker runtime to install valid values are "upstream" (Docker PPA), "nvidia" (Nvidia PPA), "apt" (Ubuntu archive), "auto" (Nvidia PPA or Ubuntu archive, based on your hardware), or "custom" (must have set `docker_runtime_repo` URL, `docker_runtime_key_url` URL and `docker_runtime_package` name).
(string) Space separated list of extra deb packages to install.
(string) Custom Docker repository validation key URL.
(string) The pinned version of nvidia-docker2 package.
(string) The name of the server which authentication tokens will be addressed to.
(string) APT Key Server
(string) List of extra apt sources, per charm-helpers standard format (a yaml list of strings encoded as a string). Each source may be either a line that can be added directly to sources.list(5), or in the form ppa:<user>/<ppa-name> for adding Personal Package Archives, or a distribution component to enable.
(string) The pinned version of nvidia-container-runtime package.