Docker Engine 20.10.0: Deprecations, API Updates, and Builder Enhancements

- Revert a change in the systemd unit that could prevent docker from starting due to a startup order conflict [docker/docker-ce-packaging#514](https://github.com/docker/docker-ce-packaging/pull/514) - buildx updated to [v0.5.0](https://github.com/docker/buildx/releases/tag/v0.5.0) [docker/docker-ce-packaging#515](https://github.com/docker/docker-ce-packaging/pull/515) ## 20.10.0 2020-12-08 ### Deprecation / Removal For an overview of all deprecated features, refer to the [Deprecated Engine Features](/engine/deprecated/) page. - Warnings and deprecation notice when `docker pull`-ing from non-compliant registries not supporting pull-by-digest [docker/cli#2872](https://github.com/docker/cli/pull/2872) - Sterner warnings and deprecation notice for unauthenticated tcp access [moby/moby#41285](https://github.com/moby/moby/pull/41285) - Deprecate KernelMemory (`docker run --kernel-memory`) [moby/moby#41254](https://github.com/moby/moby/pull/41254) [docker/cli#2652](https://github.com/docker/cli/pull/2652) - Deprecate `aufs` storage driver [docker/cli#1484](https://github.com/docker/cli/pull/1484) - Deprecate host-discovery and overlay networks with external k/v stores [moby/moby#40614](https://github.com/moby/moby/pull/40614) [moby/moby#40510](https://github.com/moby/moby/pull/40510) - Deprecate Dockerfile legacy 'ENV name value' syntax, use `ENV name=value` instead [docker/cli#2743](https://github.com/docker/cli/pull/2743) - Remove deprecated "filter" parameter for API v1.41 and up [moby/moby#40491](https://github.com/moby/moby/pull/40491) - Disable distribution manifest v2 schema 1 on push [moby/moby#41295](https://github.com/moby/moby/pull/41295) - Remove hack MalformedHostHeaderOverride breaking old docker clients (<= 1.12) in which case, set `DOCKER_API_VERSION` [moby/moby#39076](https://github.com/moby/moby/pull/39076) - Remove "docker engine" subcommands [docker/cli#2207](https://github.com/docker/cli/pull/2207) - Remove experimental "deploy" from "dab" files [docker/cli#2216](https://github.com/docker/cli/pull/2216) - Remove deprecated `docker search --automated` and `--stars` flags [docker/cli#2338](https://github.com/docker/cli/pull/2338) - No longer allow reserved namespaces in engine labels [docker/cli#2326](https://github.com/docker/cli/pull/2326) ### API - Update API version to v1.41 - Do not require "experimental" for metrics API [moby/moby#40427](https://github.com/moby/moby/pull/40427) - `GET /events` now returns `prune` events after pruning resources have completed [moby/moby#41259](https://github.com/moby/moby/pull/41259) - Prune events are returned for `container`, `network`, `volume`, `image`, and `builder`, and have a `reclaimed` attribute, indicating the amount of space reclaimed (in bytes) - Add `one-shot` stats option to not prime the stats [moby/moby#40478](https://github.com/moby/moby/pull/40478) - Adding OS version info to the system info's API (`/info`) [moby/moby#38349](https://github.com/moby/moby/pull/38349) - Add DefaultAddressPools to docker info [moby/moby#40714](https://github.com/moby/moby/pull/40714) - Add API support for PidsLimit on services [moby/moby#39882](https://github.com/moby/moby/pull/39882) ### Builder - buildkit,dockerfile: Support for `RUN --mount` options without needing to specify experimental dockerfile `#syntax` directive. [moby/buildkit#1717](https://github.com/moby/buildkit/pull/1717) - dockerfile: `ARG` command now supports defining multiple build args on the same line similarly to `ENV` [moby/buildkit#1692](https://github.com/moby/buildkit/pull/1692) - dockerfile: `--chown` flag in `ADD` now allows parameter expansion [moby/buildkit#1473](https://github.com/moby/buildkit/pull/1473) - buildkit: Fetching authorization tokens has been moved to client-side (if the client supports it). Passwords do not leak into the build daemon anymore and users can see from build output when credentials or tokens are accessed. [moby/buildkit#1660](https://github.com/moby/buildkit/pull/1660)

Docker Engine version 20.10.0 includes several deprecations and removals, such as warnings for non-compliant registries, deprecation of KernelMemory and aufs storage driver, removal of the 'filter' parameter for API v1.41, and more. The API is updated to v1.41 with enhancements like prune events, stats options, OS version info, and PidsLimit support for services. The builder now supports `RUN --mount` options without the experimental directive, allows multiple build args on the same line, and improves security by moving authorization token fetching to the client-side.