Configuring a registry

The Registry configuration is based on a YAML file, detailed below. While it comes with sane default values out of the box, you should review it exhaustively before moving your systems to production.

Override specific configuration options

In a typical setup where you run your Registry from the official image, you can specify a configuration variable from the environment by passing -e arguments to your docker run stanza or from within a Dockerfile using the ENV instruction.

To override a configuration option, create an environment variable named REGISTRY_variable where variable is the name of the configuration option and the _ (underscore) represents indention levels. For example, you can configure the rootdirectory of the filesystem storage backend:

storage:
  filesystem:
    rootdirectory: /var/lib/registry

To override this value, set an environment variable like this:

REGISTRY_STORAGE_FILESYSTEM_ROOTDIRECTORY=/somewhere

This variable overrides the /var/lib/registry value to the /somewhere directory.

Note: Create a base configuration file with environment variables that can be configured to tweak individual values. Overriding configuration sections with environment variables is not recommended.

Overriding the entire configuration file

If the default configuration is not a sound basis for your usage, or if you are having issues overriding keys from the environment, you can specify an alternate YAML configuration file by mounting it as a volume in the container.

Typically, create a new configuration file from scratch,named config.yml, then specify it in the docker run command:

$ docker run -d -p 5000:5000 --restart=always --name registry \
             -v `pwd`/config.yml:/etc/docker/registry/config.yml \
             registry:2

Use this example YAML file as a starting point.

List of configuration options

These are all configuration options for the registry. Some options in the list are mutually exclusive. Read the detailed reference information about each option before finalizing your configuration.

version: 0.1
log:
  accesslog:
    disabled: true
  level: debug
  formatter: text
  fields:
    service: registry
    environment: staging
  hooks:
    - type: mail
      disabled: true
      levels:
        - panic
      options:
        smtp:
          addr: mail.example.com:25
          username: mailuser
          password: password
          insecure: true
        from: sender@example.com
        to:
          - errors@example.com
loglevel: debug # deprecated: use "log"
storage:
  filesystem:
    rootdirectory: /var/lib/registry
    maxthreads: 100
  azure:
    accountname: accountname
    accountkey: base64encodedaccountkey
    container: containername
  gcs:
    bucket: bucketname
    keyfile: /path/to/keyfile
    rootdirectory: /gcs/object/name/prefix
    chunksize: 5242880
  s3:
    accesskey: awsaccesskey
    secretkey: awssecretkey
    region: us-west-1
    regionendpoint: http://myobjects.local
    bucket: bucketname
    encrypt: true
    keyid: mykeyid
    secure: true
    v4auth: true
    chunksize: 5242880
    multipartcopychunksize: 33554432
    multipartcopymaxconcurrency: 100
    multipartcopythresholdsize: 33554432
    rootdirectory: /s3/object/name/prefix
  swift:
    username: username
    password: password
    authurl: https://storage.myprovider.com/auth/v1.0 or https://storage.myprovider.com/v2.0 or https://storage.myprovider.com/v3/auth
    tenant: tenantname
    tenantid: tenantid
    domain: domain name for Openstack Identity v3 API
    domainid: domain id for Openstack Identity v3 API
    insecureskipverify: true
    region: fr
    container: containername
    rootdirectory: /swift/object/name/prefix
  oss:
    accesskeyid: accesskeyid
    accesskeysecret: accesskeysecret
    region: OSS region name
    endpoint: optional endpoints
    internal: optional internal endpoint
    bucket: OSS bucket
    encrypt: optional data encryption setting
    secure: optional ssl setting
    chunksize: optional size valye
    rootdirectory: optional root directory
  inmemory:  # This driver takes no parameters
  delete:
    enabled: false
  redirect:
    disable: false
  cache:
    blobdescriptor: redis
  maintenance:
    uploadpurging:
      enabled: true
      age: 168h
      interval: 24h
      dryrun: false
    readonly:
      enabled: false
auth:
  silly:
    realm: silly-realm
    service: silly-service
  token:
    realm: token-realm
    service: token-service
    issuer: registry-token-issuer
    rootcertbundle: /root/certs/bundle
  htpasswd:
    realm: basic-realm
    path: /path/to/htpasswd
middleware:
  registry:
    - name: ARegistryMiddleware
      options:
        foo: bar
  repository:
    - name: ARepositoryMiddleware
      options:
        foo: bar
  storage:
    - name: cloudfront
      options:
        baseurl: https://my.cloudfronted.domain.com/
        privatekey: /path/to/pem
        keypairid: cloudfrontkeypairid
        duration: 3000s
  storage:
    - name: redirect
      options:
        baseurl: https://example.com/
reporting:
  bugsnag:
    apikey: bugsnagapikey
    releasestage: bugsnagreleasestage
    endpoint: bugsnagendpoint
  newrelic:
    licensekey: newreliclicensekey
    name: newrelicname
    verbose: true
http:
  addr: localhost:5000
  prefix: /my/nested/registry/
  host: https://myregistryaddress.org:5000
  secret: asecretforlocaldevelopment
  relativeurls: false
  tls:
    certificate: /path/to/x509/public
    key: /path/to/x509/private
    clientcas:
      - /path/to/ca.pem
      - /path/to/another/ca.pem
    letsencrypt:
      cachefile: /path/to/cache-file
      email: emailused@letsencrypt.com
  debug:
    addr: localhost:5001
  headers:
    X-Content-Type-Options: [nosniff]
  http2:
    disabled: false
notifications:
  endpoints:
    - name: alistener
      disabled: false
      url: https://my.listener.com/event
      headers: <http.Header>
      timeout: 500
      threshold: 5
      backoff: 1000
      ignoredmediatypes:
        - application/octet-stream
redis:
  addr: localhost:6379
  password: asecret
  db: 0
  dialtimeout: 10ms
  readtimeout: 10ms
  writetimeout: 10ms
  pool:
    maxidle: 16
    maxactive: 64
    idletimeout: 300s
health:
  storagedriver:
    enabled: true
    interval: 10s
    threshold: 3
  file:
    - file: /path/to/checked/file
      interval: 10s
  http:
    - uri: http://server.to.check/must/return/200
      headers:
        Authorization: [Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==]
      statuscode: 200
      timeout: 3s
      interval: 10s
      threshold: 3
  tcp:
    - addr: redis-server.domain.com:6379
      timeout: 3s
      interval: 10s
      threshold: 3
proxy:
  remoteurl: https://registry-1.docker.io
  username: [username]
  password: [password]
compatibility:
  schema1:
    signingkeyfile: /etc/registry/key.json
validation:
  enabled: true
  manifests:
    urls:
      allow:
        - ^https?://([^/]+\.)*example\.com/
      deny:
        - ^https?://www\.example\.com/

In some instances a configuration option is optional but it contains child options marked as required. In these cases, you can omit the parent with all its children. However, if the parent is included, you must also include all the children marked required.

version

version: 0.1

The version option is required. It specifies the configuration’s version. It is expected to remain a top-level field, to allow for a consistent version check before parsing the remainder of the configuration file.

log

The log subsection configures the behavior of the logging system. The logging system outputs everything to stdout. You can adjust the granularity and format with this configuration section.

log:
  accesslog:
    disabled: true
  level: debug
  formatter: text
  fields:
    service: registry
    environment: staging

accesslog

accesslog:
  disabled: true

Within log, accesslog configures the behavior of the access logging system. By default, the access logging system outputs to stdout in Combined Log Format. Access logging can be disabled by setting the boolean flag disabled to true.

hooks

hooks:
  - type: mail
    levels:
      - panic
    options:
      smtp:
        addr: smtp.sendhost.com:25
        username: sendername
        password: password
        insecure: true
      from: name@sendhost.com
      to:
        - name@receivehost.com

The hooks subsection configures the logging hooks’ behavior. This subsection includes a sequence handler which you can use for sending mail, for example. Refer to loglevel to configure the level of messages printed.

loglevel

DEPRECATED: Please use log instead.

loglevel: debug

Permitted values are error, warn, info and debug. The default is info.

storage

storage:
  filesystem:
    rootdirectory: /var/lib/registry
  azure:
    accountname: accountname
    accountkey: base64encodedaccountkey
    container: containername
  gcs:
    bucket: bucketname
    keyfile: /path/to/keyfile
    rootdirectory: /gcs/object/name/prefix
  s3:
    accesskey: awsaccesskey
    secretkey: awssecretkey
    region: us-west-1
    regionendpoint: http://myobjects.local
    bucket: bucketname
    encrypt: true
    keyid: mykeyid
    secure: true
    v4auth: true
    chunksize: 5242880
    multipartcopychunksize: 33554432
    multipartcopymaxconcurrency: 100
    multipartcopythresholdsize: 33554432
    rootdirectory: /s3/object/name/prefix
  swift:
    username: username
    password: password
    authurl: https://storage.myprovider.com/auth/v1.0 or https://storage.myprovider.com/v2.0 or https://storage.myprovider.com/v3/auth
    tenant: tenantname
    tenantid: tenantid
    domain: domain name for Openstack Identity v3 API
    domainid: domain id for Openstack Identity v3 API
    insecureskipverify: true
    region: fr
    container: containername
    rootdirectory: /swift/object/name/prefix
  oss:
    accesskeyid: accesskeyid
    accesskeysecret: accesskeysecret
    region: OSS region name
    endpoint: optional endpoints
    internal: optional internal endpoint
    bucket: OSS bucket
    encrypt: optional data encryption setting
    secure: optional ssl setting
    chunksize: optional size valye
    rootdirectory: optional root directory
  inmemory:
  delete:
    enabled: false
  cache:
    blobdescriptor: inmemory
  maintenance:
    uploadpurging:
      enabled: true
      age: 168h
      interval: 24h
      dryrun: false
    readonly:
      enabled: false
  redirect:
    disable: false

The storage option is required and defines which storage backend is in use. You must configure exactly one backend. If you configure more, the registry returns an error. You can choose any of these backend storage drivers:

For testing only, you can use the inmemory storage driver. If you would like to run a registry from volatile memory, use the filesystem driver on a ramdisk.

If you are deploying a registry on Windows, a Windows volume mounted from the host is not recommended. Instead, you can use a S3 or Azure backing data-store. If you do use a Windows volume, the length of the PATH to the mount point must be within the MAX_PATH limits (typically 255 characters), or this error will occur:

mkdir /XXX protocol error and your registry will not function properly.

maintenance

Currently, upload purging and read-only mode are the only maintenance functions available.

uploadpurging

Upload purging is a background process that periodically removes orphaned files from the upload directories of the registry. Upload purging is enabled by default. To configure upload directory purging, the following parameters must be set.

Note: age and interval are strings containing a number with optional fraction and a unit suffix. Some examples: 45m, 2h10m, 168h.

readonly

If the readonly section under maintenance has enabled set to true, clients will not be allowed to write to the registry. This mode is useful to temporarily prevent writes to the backend storage so a garbage collection pass can be run. Before running garbage collection, the registry should be restarted with readonly’s enabled set to true. After the garbage collection pass finishes, the registry may be restarted again, this time with readonly removed from the configuration (or set to false).

delete

Use the delete structure to enable the deletion of image blobs and manifests by digest. It defaults to false, but it can be enabled by writing the following on the configuration file:

delete:
  enabled: true

cache

Use the cache structure to enable caching of data accessed in the storage backend. Currently, the only available cache provides fast access to layer metadata, which uses the blobdescriptor field if configured.

You can set blobdescriptor field to redis or inmemory. If set to redis,a Redis pool caches layer metadata. If set to inmemory, an in-memory map caches layer metadata.

NOTE: Formerly, blobdescriptor was known as layerinfo. While these are equivalent, layerinfo has been deprecated.

redirect

The redirect subsection provides configuration for managing redirects from content backends. For backends that support it, redirecting is enabled by default. In certain deployment scenarios, you may decide to route all data through the Registry, rather than redirecting to the backend. This may be more efficient when using a backend that is not co-located or when a registry instance is aggressively caching.

To disable redirects, add a single flag disable, set to true under the redirect section:

redirect:
  disable: true

auth

auth:
  silly:
    realm: silly-realm
    service: silly-service
  token:
    realm: token-realm
    service: token-service
    issuer: registry-token-issuer
    rootcertbundle: /root/certs/bundle
  htpasswd:
    realm: basic-realm
    path: /path/to/htpasswd

The auth option is optional. Possible auth providers include:

• silly
• token
• htpasswd

You can configure only one authentication provider.

silly

The silly authentication provider is only appropriate for development. It simply checks for the existence of the Authorization header in the HTTP request. It does not check the header’s value. If the header does not exist, the silly auth responds with a challenge response, echoing back the realm, service, and scope for which access was denied.

The following values are used to configure the response:

token

Token-based authentication allows you to decouple the authentication system from the registry. It is an established authentication paradigm with a high degree of security.

For more information about Token based authentication configuration, see the specification.

htpasswd

The htpasswd authentication backed allows you to configure basic authentication using an Apache htpasswd file. The only supported password format is bcrypt. Entries with other hash types are ignored. The htpasswd file is loaded once, at startup. If the file is invalid, the registry will display an error and will not start.

Warning: Only use the htpasswd authentication scheme with TLS configured, since basic authentication sends passwords as part of the HTTP header.

middleware

The middleware structure is optional. Use this option to inject middleware at named hook points. Each middleware must implement the same interface as the object it is wrapping. For instance, a registry middleware must implement the distribution.Namespace interface, while a repository middleware must implement distribution.Repository, and a storage middleware must implement driver.StorageDriver.

This is an example configuration of the cloudfront middleware, a storage middleware:

middleware:
  registry:
    - name: ARegistryMiddleware
      options:
        foo: bar
  repository:
    - name: ARepositoryMiddleware
      options:
        foo: bar
  storage:
    - name: cloudfront
      options:
        baseurl: https://my.cloudfronted.domain.com/
        privatekey: /path/to/pem
        keypairid: cloudfrontkeypairid
        duration: 3000s

Each middleware entry has name and options entries. The name must correspond to the name under which the middleware registers itself. The options field is a map that details custom configuration required to initialize the middleware. It is treated as a map[string]interface{}. As such, it supports any interesting structures desired, leaving it up to the middleware initialization function to best determine how to handle the specific interpretation of the options.

cloudfront

redirect

You can use the redirect storage middleware to specify a custom URL to a location of a proxy for the layer stored by the S3 storage driver.

reporting

reporting:
  bugsnag:
    apikey: bugsnagapikey
    releasestage: bugsnagreleasestage
    endpoint: bugsnagendpoint
  newrelic:
    licensekey: newreliclicensekey
    name: newrelicname
    verbose: true

The reporting option is optional and configures error and metrics reporting tools. At the moment only two services are supported:

• Bugsnag
• New Relic

A valid configuration may contain both.

bugsnag

newrelic

http

http:
  addr: localhost:5000
  net: tcp
  prefix: /my/nested/registry/
  host: https://myregistryaddress.org:5000
  secret: asecretforlocaldevelopment
  relativeurls: false
  tls:
    certificate: /path/to/x509/public
    key: /path/to/x509/private
    clientcas:
      - /path/to/ca.pem
      - /path/to/another/ca.pem
    letsencrypt:
      cachefile: /path/to/cache-file
      email: emailused@letsencrypt.com
  debug:
    addr: localhost:5001
  headers:
    X-Content-Type-Options: [nosniff]
  http2:
    disabled: false

The http option details the configuration for the HTTP server that hosts the registry.

tls

The tls structure within http is optional. Use this to configure TLS for the server. If you already have a web server running on the same host as the registry, you may prefer to configure TLS on that web server and proxy connections to the registry server.

letsencrypt

The letsencrypt structure within tls is optional. Use this to configure TLS certificates provided by Let’s Encrypt.

NOTE: When using Let’s Encrypt, ensure that the outward-facing address is accessible on port 443. The registry defaults to listening on port 5000. If you run the registry as a container, consider adding the flag -p 443:5000 to the docker run command or using a similar setting in a cloud configuration.

debug

The debug option is optional . Use it to configure a debug server that can be helpful in diagnosing problems. The debug endpoint can be used for monitoring registry metrics and health, as well as profiling. Sensitive information may be available via the debug endpoint. Please be certain that access to the debug endpoint is locked down in a production environment.

The debug section takes a single required addr parameter, which specifies the HOST:PORT on which the debug server should accept connections.

headers

The headers option is optional . Use it to specify headers that the HTTP server should include in responses. This can be used for security headers such as Strict-Transport-Security.

The headers option should contain an option for each header to include, where the parameter name is the header’s name, and the parameter value a list of the header’s payload values.

Including X-Content-Type-Options: [nosniff] is recommended, so that browsers will not interpret content as HTML if they are directed to load a page from the registry. This header is included in the example configuration file.

http2

The http2 structure within http is optional. Use this to control http2 settings for the registry.

notifications

notifications:
  endpoints:
    - name: alistener
      disabled: false
      url: https://my.listener.com/event
      headers: <http.Header>
      timeout: 500
      threshold: 5
      backoff: 1000
      ignoredmediatypes:
        - application/octet-stream

The notifications option is optional and currently may contain a single option, endpoints.

endpoints

The endpoints structure contains a list of named services (URLs) that can accept event notifications.

redis

redis:
  addr: localhost:6379
  password: asecret
  db: 0
  dialtimeout: 10ms
  readtimeout: 10ms
  writetimeout: 10ms
  pool:
    maxidle: 16
    maxactive: 64
    idletimeout: 300s

Declare parameters for constructing the redis connections. Registry instances may use the Redis instance for several applications. Currently, it caches information about immutable blobs. Most of the redis options control how the registry connects to the redis instance. You can control the pool’s behavior with the pool subsection.

You should configure Redis with the allkeys-lru eviction policy, because the registry does not set an expiration value on keys.

pool

pool:
  maxidle: 16
  maxactive: 64
  idletimeout: 300s

Use these settings to configure the behavior of the Redis connection pool.

health

health:
  storagedriver:
    enabled: true
    interval: 10s
    threshold: 3
  file:
    - file: /path/to/checked/file
      interval: 10s
  http:
    - uri: http://server.to.check/must/return/200
      headers:
        Authorization: [Basic QWxhZGRpbjpvcGVuIHNlc2FtZQ==]
      statuscode: 200
      timeout: 3s
      interval: 10s
      threshold: 3
  tcp:
    - addr: redis-server.domain.com:6379
      timeout: 3s
      interval: 10s
      threshold: 3

The health option is optional, and contains preferences for a periodic health check on the storage driver’s backend storage, as well as optional periodic checks on local files, HTTP URIs, and/or TCP servers. The results of the health checks are available at the /debug/health endpoint on the debug HTTP server if the debug HTTP server is enabled (see http section).

storagedriver

The storagedriver structure contains options for a health check on the configured storage driver’s backend storage. The health check is only active when enabled is set to true.

file

The file structure includes a list of paths to be periodically checked for the\ existence of a file. If a file exists at the given path, the health check will fail. You can use this mechanism to bring a registry out of rotation by creating a file.

http

The http structure includes a list of HTTP URIs to periodically check with HEAD requests. If a HEAD request does not complete or returns an unexpected status code, the health check will fail.

tcp

The tcp structure includes a list of TCP addresses to periodically check using TCP connection attempts. Addresses must include port numbers. If a connection attempt fails, the health check will fail.

proxy

proxy:
  remoteurl: https://registry-1.docker.io
  username: [username]
  password: [password]

The proxy structure allows a registry to be configured as a pull-through cache to Docker Hub. See mirror for more information. Pushing to a registry configured as a pull-through cache is unsupported.

To enable pulling private repositories (e.g. batman/robin) specify the username (such as batman) and the password for that username.

Note: These private repositories are stored in the proxy cache’s storage. Take appropriate measures to protect access to the proxy cache.

compatibility

compatibility:
  schema1:
    signingkeyfile: /etc/registry/key.json

Use the compatibility structure to configure handling of older and deprecated features. Each subsection defines such a feature with configurable behavior.

schema1

validation

validation:
  enabled: true
  manifests:
    urls:
      allow:
        - ^https?://([^/]+\.)*example\.com/
      deny:
        - ^https?://www\.example\.com/

enabled

Use the enabled flag to enable the other options in the validation section. They are disabled by default.

manifests

Use the manifest subsection to configure manifest validation.

urls

The allow and deny options are each a list of regular expressions that restrict the URLs in pushed manifests.

If allow is unset, pushing a manifest containing URLs fails.

If allow is set, pushing a manifest succeeds only if all URLs match one of the allow regular expressions and one of the following holds:

1. deny is unset.
2. deny is set but no URLs within the manifest match any of the deny regular expressions.

Example: Development configuration

You can use this simple example for local development:

version: 0.1
log:
  level: debug
storage:
    filesystem:
        rootdirectory: /var/lib/registry
http:
    addr: localhost:5000
    secret: asecretforlocaldevelopment
    debug:
        addr: localhost:5001

This example configures the registry instance to run on port 5000, binding to localhost, with the debug server enabled. Registry data is stored in the /var/lib/registry directory. Logging is set to debug mode, which is the most verbose.

See config-example.yml for another simple configuration. Both examples are generally useful for local development.

Example: Middleware configuration

This example configures Amazon Cloudfront as the storage middleware in a registry. Middleware allows the registry to serve layers via a content delivery network (CDN). This reduces requests to the storage layer.

Cloudfront requires the S3 storage driver.

This is the configuration expressed in YAML:

middleware:
  storage:
  - name: cloudfront
    disabled: false
    options:
      baseurl: http://d111111abcdef8.cloudfront.net
      privatekey: /path/to/asecret.pem
      keypairid: asecret
      duration: 60

See the configuration reference for Cloudfront for more information about configuration options.

Note: Cloudfront keys exist separately from other AWS keys. See the documentation on AWS credentials for more information.