Docker-registry charm
This charm provides a registry for storage and distribution of docker images. See https://docs.docker.com/registry/ for details.
Deployment
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 cs:~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 cs:~containers/docker-registry
juju deploy cs:~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 \
tls-key-path=/home/ubuntu/cert.key
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=$(base64 /path/to/key)
Proxied Registry
This charm supports an http proxy relation that allows operators to
control how the registry is exposed on the network. This is achieved by
deploying and relating to a proxy provider, such as haproxy:
juju deploy cs:~containers/docker-registry
juju deploy haproxy
juju add-relation haproxy docker-registry
When multiple docker-registry units are deployed, the proxy will be
configured with one unit chosen as the primary proxied service with remaining
units configured as backups. This provides a highly available deployment that
will fail over to a backup if the primary service becomes unavailable.
Note: HA deployments require the proxy to be in
active-passivepeering mode, which is the default forhaproxy.
TLS/SSL
TLS is supported between haproxy and docker-registry, though some manual
configuration is required. You will need to transfer the registry CA certificate
to the proxy so the registry certificate can be verified. The path to the
CA must match on both registry and proxy units. For example:
juju run --unit haproxy/$UNIT_NUM 'mkdir -p /etc/docker/registry'
juju run --unit haproxy/$UNIT_NUM 'chown ubuntu:ubuntu /etc/docker/registry'
juju scp docker-registry/$UNIT_NUM:/etc/docker/registry/ca.crt ./ca.crt
juju scp ./ca.crt haproxy/$UNIT_NUM:/etc/docker/registry
Nagios Monitoring
This charm supports monitoring with nagios:
juju deploy cs:~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.
Actions
Adding 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.
Listing Images
List images known to the registry with the images action:
juju run-action --wait docker-registry/0 images \
options=<extra-args> repository=<repository[:tag]>
This runs docker images on the registry machine. The optional options and
repository parameters are passed through to the underlying command. For
example, show non-truncated output with numeric image IDs:
juju run-action --wait docker-registry/0 images \
options="--no-trunc --quiet"
Removing Images
Remove images from the registry with the rmi action:
juju run-action --wait docker-registry/0 rmi \
options=<extra-args> image=<image [image...]>
This runs docker rmi on the registry machine. The image name (or space
separated names) must be specified using the image parameter. The optional
options parameter is passed through to the underlying command. For
example, remove the ubuntu:18.04 image without deleting untagged parents:
juju run-action --wait docker-registry/0 rmi \
options="--no-prune" image="ubuntu:18.04"
Starting/Stopping
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
Configuration
| name | type | Default | Description |
|---|---|---|---|
| apt-key-server | string | See notes | APT Key Server |
| auth-basic-password | string | Password for basic (htpasswd) authentication. Set this to something other than an empty string to configure basic auth for the registry. | |
| auth-basic-user | string | admin | Username for basic (htpasswd) authentication. |
| auth-token-issuer | string | The name on the certificate that authentication tokens must me signed by. | |
| auth-token-realm | string | The location from which clients should fetch authentication tokens. | |
| auth-token-root-certs | string | The root certificate bundle (base64 encoded) for the authentication tokens. | |
| auth-token-service | string | The name of the server which authentication tokens will be addressed to. | |
| cuda_repo | string | 10.0.130-1 | The cuda-repo package version to install. |
| docker-ce-package | string | See notes | The pinned version of docker-ce package installed with nvidia-docker. |
| docker-opts | string | Extra options to pass to the Docker daemon. e.g. --insecure-registry. | |
| docker_runtime | string | auto | See notes |
| docker_runtime_key_url | string | Custom Docker repository validation key URL. | |
| docker_runtime_package | string | Custom Docker repository package name. | |
| docker_runtime_repo | string | See notes | |
| enable-cgroups | boolean | False | Enable GRUB cgroup overrides cgroup_enable=memory swapaccount=1. WARNING changing this option will reboot the host - use with caution on production services. |
| extra_packages | string | Space separated list of extra deb packages to install. | |
| http-host | string | See notes | |
| http_proxy | 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. | |
| https_proxy | 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. | |
| install_from_upstream | boolean | False | Toggle installation from Ubuntu archive vs the Docker PPA (DEPRECATED; please use docker_runtime instead). |
| install_keys | string | See notes | |
| install_sources | string | See notes | |
| log-level | string | info | Logging output level ('error', 'warn', 'info', or 'debug'). |
| nagios_context | string | juju | See notes |
| nagios_servicegroups | string | A comma-separated list of nagios servicegroups. If left empty, the nagios_context will be used as the servicegroup | |
| no_proxy | string | See notes | |
| nvidia-container-runtime-package | string | See notes | The pinned version of nvidia-container-runtime package. |
| nvidia-docker-package | string | See notes | The pinned version of nvidia-docker2 package. |
| package_status | string | install | The status of service-affecting packages will be set to this value in the dpkg database. Valid values are "install" and "hold". |
| registry-image | string | registry:2 | Registry image. |
| registry-name | string | registry | Name of the registry container. |
| registry-port | int | 5000 | The external port on which the docker registry listens. |
| storage-delete | boolean | False | Enable/disable the "delete" storage option. False, the default, disables this option in the registry config file. |
| storage-read-only | boolean | False | Enable/disable the "readonly" storage maintenance option. False, the default, disables this option in the registry config file. |
| storage-swift-authurl | string | The URL of the keystone used to authenticate to swift. | |
| storage-swift-container | string | docker-registry | The name of the swift container that will hold the images. |
| storage-swift-domain | string | OpenStack Identity v3 API domain. | |
| storage-swift-password | string | The password to use to access swift. | |
| storage-swift-region | string | The region containing the swift service. | |
| storage-swift-tenant | string | The tenant containing the swift service. | |
| storage-swift-username | string | The username to use to access swift. | |
| tls-ca-blob | string | Base64 encoded TLS CA certificate (overwrites tls-cert-path file). | |
| tls-ca-path | string | See notes | Path to the TLS CA certificate. |
| tls-cert-blob | string | Base64 encoded TLS certificate (overwrites tls-cert-path file). | |
| tls-cert-path | string | See notes | Path to the TLS certificate. |
| tls-key-blob | string | Base64 encoded TLS certificate private key (overwrites tls-key-path file). | |
| tls-key-path | string | See notes | Path to the TLS certificate private key. |
apt-key-server
hkp://keyserver.ubuntu.com:80
docker-ce-package
docker-ce=5:18.09.1~3-0~ubuntu-bionic
docker_runtime
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).
docker_runtime_repo
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}] https://download.docker.com/linux/ubuntu {CODE} stable.
http-host
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 "https://example.com/docker-registry/". Any path component must include a trailing "/". If this is not configured then the docker registry will derive its location from the incoming requests.
install_keys
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.
install_sources
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:
nagios_context
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.
no_proxy
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.
nvidia-container-runtime-package
nvidia-container-runtime=2.0.0+docker18.09.1-1
nvidia-docker-package
nvidia-docker2=2.0.3+docker18.09.1-1
tls-ca-path
/etc/docker/registry/ca.crt
tls-cert-path
/etc/docker/registry/registry.crt
tls-key-path
/etc/docker/registry/registry.key
Authentication
This charm supports basic (htpasswd) as well as token-based authentication. Configure either method as follows:
juju config docker-registry \
auth-basic-user='admin' \
auth-basic-password='redrum'
juju config docker-registry \
auth-token-issuer='auth.example.com' \
auth-token-realm='myorg' \
auth-token-root-certs='$(base64 /path/to/file)' \
auth-token-service='myapp'
Delete by digest
The recommended way to delete images from the registry is to use the rmi
action. If necessary, this charm can be configured to
allow deletion of blobs and manifests by digest by setting
the storage-delete config option to true:
juju config docker-registry storage-delete=true
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> \
storage-swift-username=<user>
Note: If any of the above config options are set, then they must all be set. Optional params are noted below.
It is possible to configure the swift backend with an OpenStack domain name for Identity v3. To enable this, set the following optional config parameter:
storage-swift-domain=<val>
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 https://github.com/docker/distribution/issues/2292, upload an empty file called "files" at the root of the container to workaround the issue.