Deprecated Engine Features

This page provides an overview of features that are deprecated in Engine. Changes in packaging, and supported (Linux) distributions are not included. To learn about end of support for Linux distributions, refer to the release notes.

Feature Deprecation Policy

As changes are made to Docker there may be times when existing features need to be removed or replaced with newer features. Before an existing feature is removed it is labeled as “deprecated” within the documentation and remains in Docker for at least one stable release unless specified explicitly otherwise. After that time it may be removed.

Users are expected to take note of the list of deprecated features each release and plan their migration away from those features, and (if applicable) towards the replacement features as soon as possible.

Deprecated Engine Features

The table below provides an overview of the current status of deprecated features:

• Deprecated: the feature is marked “deprecated” and should no longer be used. The feature may be removed, disabled, or change behavior in a future release. The “Deprecated” column contains the release in which the feature was marked deprecated, whereas the “Remove” column contains a tentative release in which the feature is to be removed. If no release is included in the “Remove” column, the release is yet to be decided on.
• Removed: the feature was removed, disabled, or hidden. Refer to the linked section for details. Some features are “soft” deprecated, which means that they remain functional for backward compatibility, and to allow users to migrate to alternatives. In such cases, a warning may be printed, and users should not rely on this feature.

Support for encrypted TLS private keys

Deprecated in Release: v20.10

Use of encrypted TLS private keys has been deprecated, and will be removed in a future release. Golang has deprecated support for legacy PEM encryption (as specified in RFC 1423), as it is insecure by design (see https://go-review.googlesource.com/c/go/+/264159).

Kubernetes stack and context support

Deprecated in Release: v20.10

Following the deprecation of Compose on Kubernetes, support for Kubernetes in the stack and context commands in the docker CLI is now marked as deprecated as well.

Pulling images from non-compliant image registries

Deprecated in Release: v20.10

Docker Engine v20.10 and up includes optimizations to verify if images in the local image cache need updating before pulling, preventing the Docker Engine from making unnecessary API requests. These optimizations require the container image registry to conform to the Open Container Initiative Distribution Specification.

While most registries conform to the specification, we encountered some registries to be non-compliant, resulting in docker pull to fail.

As a temporary solution, Docker Engine v20.10 includes a fallback mechanism to allow docker pull to be functional when using a non-compliant registry. A warning message is printed in this situation:

WARNING Failed to pull manifest by the resolved digest. This registry does not
        appear to conform to the distribution registry specification; falling back to
        pull by tag. This fallback is DEPRECATED, and will be removed in a future
        release.

The fallback is added to allow users to either migrate their images to a compliant registry, or for these registries to become compliant.

Note that this fallback only addresses failures on docker pull. Other commands, such as docker stack deploy, or pulling images with containerd will continue to fail.

Given that other functionality is still broken with these registries, we consider this fallback a temporary solution, and will remove the fallback in an upcoming major release.

Linux containers on Windows (LCOW) (experimental)

Deprecated in Release: v20.10

The experimental feature to run Linux containers on Windows (LCOW) was introduced as a technical preview in Docker 17.09. While many enhancements were made after its introduction, the feature never reached completeness, and development has now stopped in favor of running docker natively on Linux in WSL2.

Developers who want to run Linux workloads on a Windows host are encouraged to use Docker Desktop with WSL2 instead.

BLKIO weight options with cgroups v1

Deprecated in Release: v20.10

Specifying blkio weight (docker run --blkio-weight and docker run --blkio-weight-device) is now marked as deprecated when using cgroups v1 because the corresponding features were removed in Linux kernel v5.0 and up. When using cgroups v2, the --blkio-weight options are implemented using `io.weight.

Kernel memory limit

Deprecated in Release: v20.10

Specifying kernel memory limit (docker run --kernel-memory) is now marked as deprecated, as Linux kernel deprecated kmem.limit_in_bytes in v5.4.

Classic Swarm and overlay networks using cluster store

Deprecated in Release: v20.10

Standalone (“classic”) Swarm has been deprecated, and with that the use of overlay networks using an external key/value store. The corresponding--cluster-advertise, --cluster-store, and --cluster-store-opt daemon options have been marked deprecated, and will be disabled or removed in a future release.

Support for legacy ~/.dockercfg configuration files

Deprecated in Release: v20.10

The docker CLI up until v1.7.0 used the ~/.dockercfg file to store credentials after authenticating to a registry (docker login). Docker v1.7.0 replaced this file with a new CLI configuration file, located in ~/.docker/config.json. When implementing the new configuration file, the old file (and file-format) was kept as a fall-back, to assist existing users with migrating to the new file.

Given that the old file format encourages insecure storage of credentials (credentials are stored unencrypted), and that no version of the CLI since Docker v1.7.0 has created this file, the file is marked deprecated, and support for this file will be removed in a future release.

Configuration options for experimental CLI features

The DOCKER_CLI_EXPERIMENTAL environment variable and the corresponding experimental field in the CLI configuration file are deprecated. Experimental features will be enabled by default, and these configuration options will no longer be functional.

CLI plugins support

Deprecated in Release: v20.10

CLI Plugin API is now marked as deprecated.

Dockerfile legacy ENV name value syntax

Deprecated in Release: v20.10

The Dockerfile ENV instruction allows values to be set using either ENV name=value or ENV name value. The latter (ENV name value) form can be ambiguous, for example, the following defines a single env-variable (ONE) with value "TWO= THREE=world", but may have intended to be setting three env-vars:

ENV ONE TWO= THREE=world

This format also does not allow setting multiple environment-variables in a single ENV line in the Dockerfile.

Use of the ENV name value syntax is discouraged, and may be removed in a future release. Users are encouraged to update their Dockerfiles to use the ENV name=value syntax, for example:

ENV ONE="" TWO="" THREE="world"

docker build --stream flag (experimental)

Deprecated in Release: v20.10 Removed in Release: v20.10

Docker v17.07 introduced an experimental --stream flag on docker build which allowed the build-context to be incrementally sent to the daemon, instead of unconditionally sending the whole build-context.

This functionality has been reimplemented as part of BuildKit, which uses streaming by default and the --stream option will be ignored when using the classic builder, printing a deprecation warning instead.

Users that want to use this feature are encouraged to enable BuildKit by setting the DOCKER_BUILDKIT=1 environment variable or through the daemon or CLI configuration files.

fluentd-async-connect log opt

Deprecated in Release: v20.10

The --log-opt fluentd-async-connect option for the fluentd logging driver is deprecated in favor of --log-opt fluentd-async. A deprecation message is logged in the daemon logs if the old option is used:

fluent#New: AsyncConnect is now deprecated, please use Async instead

Users are encouraged to use the fluentd-async option going forward, as support for the old option will be removed in a future release.

Pushing and pulling with image manifest v2 schema 1

Deprecated in Release: v19.03

Target For Removal In Release: v20.10

The image manifest v2 schema 1 format is deprecated in favor of the v2 schema 2 format.

If the registry you are using still supports v2 schema 1, urge their administrators to move to v2 schema 2.

docker engine subcommands

Deprecated in Release: v19.03

Removed in Release: v20.10

The docker engine activate, docker engine check, and docker engine update provided an alternative installation method to upgrade Docker Community engines to Docker Enterprise, using an image-based distribution of the Docker Engine.

This feature was only available on Linux, and only when executed on a local node. Given the limitations of this feature, and the feature not getting widely adopted, the docker engine subcommands will be removed, in favor of installation through standard package managers.

Top-level docker deploy subcommand (experimental)

Deprecated in Release: v19.03

Removed in Release: v20.10

The top-level docker deploy command (using the “Docker Application Bundle” (.dab) file format was introduced as an experimental feature in Docker 1.13 / 17.03, but superseded by support for Docker Compose files using the docker stack deploy subcommand.

docker stack deploy using “dab” files (experimental)

Deprecated in Release: v19.03

Removed in Release: v20.10

With no development being done on this feature, and no active use of the file format, support for the DAB file format and the top-level docker deploy command (hidden by default in 19.03), will be removed, in favour of docker stack deploy using compose files.

AuFS storage driver

Deprecated in Release: v19.03

The aufs storage driver is deprecated in favor of overlay2, and will be removed in a future release. Users of the aufs storage driver are recommended to migrate to a different storage driver, such as overlay2, which is now the default storage driver.

The aufs storage driver facilitates running Docker on distros that have no support for OverlayFS, such as Ubuntu 14.04 LTS, which originally shipped with a 3.14 kernel.

Now that Ubuntu 14.04 is no longer a supported distro for Docker, and overlay2 is available to all supported distros (as they are either on kernel 4.x, or have support for multiple lowerdirs backported), there is no reason to continue maintenance of the aufs storage driver.

Legacy “overlay” storage driver

Deprecated in Release: v18.09

The overlay storage driver is deprecated in favor of the overlay2 storage driver, which has all the benefits of overlay, without its limitations (excessive inode consumption). The legacy overlay storage driver will be removed in a future release. Users of the overlay storage driver should migrate to the overlay2 storage driver.

The legacy overlay storage driver allowed using overlayFS-backed filesystems on pre 4.x kernels. Now that all supported distributions are able to run overlay2 (as they are either on kernel 4.x, or have support for multiple lowerdirs backported), there is no reason to keep maintaining the overlay storage driver.

Device mapper storage driver

Deprecated in Release: v18.09

The devicemapper storage driver is deprecated in favor of overlay2, and will be removed in a future release. Users of the devicemapper storage driver are recommended to migrate to a different storage driver, such as overlay2, which is now the default storage driver.

The devicemapper storage driver facilitates running Docker on older (3.x) kernels that have no support for other storage drivers (such as overlay2, or AUFS).

Now that support for overlay2 is added to all supported distros (as they are either on kernel 4.x, or have support for multiple lowerdirs backported), there is no reason to continue maintenance of the devicemapper storage driver.

Use of reserved namespaces in engine labels

Deprecated in Release: v18.06

Removed In Release: v20.10

The namespaces com.docker.*, io.docker.*, and org.dockerproject.* in engine labels were always documented to be reserved, but there was never any enforcement.

Usage of these namespaces will now cause a warning in the engine logs to discourage their use, and will error instead in v20.10 and above.

--disable-legacy-registry override daemon option

Disabled In Release: v17.12

Removed In Release: v19.03

The --disable-legacy-registry flag was disabled in Docker 17.12 and will print an error when used. For this error to be printed, the flag itself is still present, but hidden. The flag has been removed in Docker 19.03.

Interacting with V1 registries

Disabled By Default In Release: v17.06

Removed In Release: v17.12

Version 1.8.3 added a flag (--disable-legacy-registry=false) which prevents the docker daemon from pull, push, and login operations against v1 registries. Though enabled by default, this signals the intent to deprecate the v1 protocol.

Support for the v1 protocol to the public registry was removed in 1.13. Any mirror configurations using v1 should be updated to use a v2 registry mirror.

Starting with Docker 17.12, support for V1 registries has been removed, and the --disable-legacy-registry flag can no longer be used, and dockerd will fail to start when set.

Asynchronous service create and service update as default

Deprecated In Release: v17.05

Disabled by default in release: v17.10

Docker 17.05 added an optional --detach=false option to make the docker service create and docker service update work synchronously. This option will be enabled by default in Docker 17.10, at which point the --detach flag can be used to use the previous (asynchronous) behavior.

The default for this option will also be changed accordingly for docker service rollback and docker service scale in Docker 17.10.

-g and --graph flags on dockerd

Deprecated In Release: v17.05

The -g or --graph flag for the dockerd or docker daemon command was used to indicate the directory in which to store persistent data and resource configuration and has been replaced with the more descriptive --data-root flag.

These flags were added before Docker 1.0, so will not be removed, only hidden, to discourage their use.

Top-level network properties in NetworkSettings

Deprecated In Release: v1.13.0

Target For Removal In Release: v17.12

When inspecting a container, NetworkSettings contains top-level information about the default (“bridge”) network;

EndpointID, Gateway, GlobalIPv6Address, GlobalIPv6PrefixLen, IPAddress, IPPrefixLen, IPv6Gateway, and MacAddress.

These properties are deprecated in favor of per-network properties in NetworkSettings.Networks. These properties were already “deprecated” in docker 1.9, but kept around for backward compatibility.

Refer to #17538 for further information.

filter param for /images/json endpoint

Deprecated In Release: v1.13.0

Removed In Release: v20.10

The filter param to filter the list of image by reference (name or name:tag) is now implemented as a regular filter, named reference.

repository:shortid image references

Deprecated In Release: v1.13.0

Removed In Release: v17.12

The repository:shortid syntax for referencing images is very little used, collides with tag references, and can be confused with digest references.

Support for the repository:shortid notation to reference images was removed in Docker 17.12.

docker daemon subcommand

Deprecated In Release: v1.13.0

Removed In Release: v17.12

The daemon is moved to a separate binary (dockerd), and should be used instead.

Duplicate keys with conflicting values in engine labels

Deprecated In Release: v1.13.0

Removed In Release: v17.12

When setting duplicate keys with conflicting values, an error will be produced, and the daemon will fail to start.

MAINTAINER in Dockerfile

Deprecated In Release: v1.13.0

MAINTAINER was an early very limited form of LABEL which should be used instead.

API calls without a version

Deprecated In Release: v1.13.0

Target For Removal In Release: v17.12

API versions should be supplied to all API calls to ensure compatibility with future Engine versions. Instead of just requesting, for example, the URL /containers/json, you must now request /v1.25/containers/json.

Backing filesystem without d_type support for overlay/overlay2

Deprecated In Release: v1.13.0

Removed In Release: v17.12

The overlay and overlay2 storage driver does not work as expected if the backing filesystem does not support d_type. For example, XFS does not support d_type if it is formatted with the ftype=0 option.

Starting with Docker 17.12, new installations will not support running overlay2 on a backing filesystem without d_type support. For existing installations that upgrade to 17.12, a warning will be printed.

Please also refer to #27358 for further information.

--automated and --stars flags on docker search

Deprecated in Release: v1.12.0

Removed In Release: v20.10

The docker search --automated and docker search --stars options are deprecated. Use docker search --filter=is-automated=<true|false> and docker search --filter=stars=... instead.

-h shorthand for --help

Deprecated In Release: v1.12.0

Target For Removal In Release: v17.09

The shorthand (-h) is less common than --help on Linux and cannot be used on all subcommands (due to it conflicting with, e.g. -h / --hostname on docker create). For this reason, the -h shorthand was not printed in the “usage” output of subcommands, nor documented, and is now marked “deprecated”.

-e and --email flags on docker login

Deprecated In Release: v1.11.0

Removed In Release: v17.06

The docker login command is removing the ability to automatically register for an account with the target registry if the given username doesn’t exist. Due to this change, the email flag is no longer required, and will be deprecated.

Separator (:) of --security-opt flag on docker run

Deprecated In Release: v1.11.0

Target For Removal In Release: v17.06

The flag --security-opt doesn’t use the colon separator (:) anymore to divide keys and values, it uses the equal symbol (=) for consistency with other similar flags, like --storage-opt.

Ambiguous event fields in API

Deprecated In Release: v1.10.0

The fields ID, Status and From in the events API have been deprecated in favor of a more rich structure. See the events API documentation for the new format.

-f flag on docker tag

Deprecated In Release: v1.10.0

Removed In Release: v1.12.0

To make tagging consistent across the various docker commands, the -f flag on the docker tag command is deprecated. It is not longer necessary to specify -f to move a tag from one image to another. Nor will docker generate an error if the -f flag is missing and the specified tag is already in use.

HostConfig at API container start

Deprecated In Release: v1.10.0

Removed In Release: v1.12.0

Passing an HostConfig to POST /containers/{name}/start is deprecated in favor of defining it at container creation (POST /containers/create).

--before and --since flags on docker ps

Deprecated In Release: v1.10.0

Removed In Release: v1.12.0

The docker ps --before and docker ps --since options are deprecated. Use docker ps --filter=before=... and docker ps --filter=since=... instead.

Driver-specific log tags

Deprecated In Release: v1.9.0

Removed In Release: v1.12.0

Log tags are now generated in a standard way across different logging drivers. Because of which, the driver specific log tag options syslog-tag, gelf-tag and fluentd-tag have been deprecated in favor of the generic tag option.

$ docker --log-driver=syslog --log-opt tag="{{.ImageName}}/{{.Name}}/{{.ID}}"

Docker Content Trust ENV passphrase variables name change

Deprecated In Release: v1.9.0

Removed In Release: v1.12.0

Since 1.9, Docker Content Trust Offline key has been renamed to Root key and the Tagging key has been renamed to Repository key. Due to this renaming, we’re also changing the corresponding environment variables

• DOCKER_CONTENT_TRUST_OFFLINE_PASSPHRASE is now named DOCKER_CONTENT_TRUST_ROOT_PASSPHRASE
• DOCKER_CONTENT_TRUST_TAGGING_PASSPHRASE is now named DOCKER_CONTENT_TRUST_REPOSITORY_PASSPHRASE

/containers/(id or name)/copy endpoint

Deprecated In Release: v1.8.0

Removed In Release: v1.12.0

The endpoint /containers/(id or name)/copy is deprecated in favor of /containers/(id or name)/archive.

LXC built-in exec driver

Deprecated In Release: v1.8.0

Removed In Release: v1.10.0

The built-in LXC execution driver, the lxc-conf flag, and API fields have been removed.

Old Command Line Options

Deprecated In Release: v1.8.0

Removed In Release: v1.10.0

The flags -d and --daemon are deprecated in favor of the daemon subcommand:

docker daemon -H ...

The following single-dash (-opt) variant of certain command line options are deprecated and replaced with double-dash options (--opt):

docker attach -nostdin
docker attach -sig-proxy
docker build -no-cache
docker build -rm
docker commit -author
docker commit -run
docker events -since
docker history -notrunc
docker images -notrunc
docker inspect -format
docker ps -beforeId
docker ps -notrunc
docker ps -sinceId
docker rm -link
docker run -cidfile
docker run -dns
docker run -entrypoint
docker run -expose
docker run -link
docker run -lxc-conf
docker run -n
docker run -privileged
docker run -volumes-from
docker search -notrunc
docker search -stars
docker search -t
docker search -trusted
docker tag -force

The following double-dash options are deprecated and have no replacement:

docker run --cpuset
docker run --networking
docker ps --since-id
docker ps --before-id
docker search --trusted

Deprecated In Release: v1.5.0

Removed In Release: v1.12.0

The single-dash (-help) was removed, in favor of the double-dash --help

docker -help
docker [COMMAND] -help

--api-enable-cors flag on dockerd

Deprecated In Release: v1.6.0

Removed In Release: v17.09

The flag --api-enable-cors is deprecated since v1.6.0. Use the flag --api-cors-header instead.

--run flag on docker commit

Deprecated In Release: v0.10.0

Removed In Release: v1.13.0

The flag --run of the docker commit (and its short version -run) were deprecated in favor of the --changes flag that allows to pass Dockerfile commands.

Three arguments form in docker import

Deprecated In Release: v0.6.7

Removed In Release: v1.12.0

The docker import command format file|URL|- [REPOSITORY [TAG]] is deprecated since November 2013. It’s no more supported.

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