Docker API Updates: Cgroup Mounts, Network Prioritization, and Removals

- `POST /containers/create` now accepts a `writable-cgroups=true` option in `HostConfig.SecurityOpt` to mount the container's cgroups writable. This provides a more granular approach than `HostConfig.Privileged`. [moby/moby#48828](https://github.com/moby/moby/pull/48828) - `POST /build/prune` renames `keep-bytes` to `reserved-space` and now supports additional prune parameters `max-used-space` and `min-free-space`. [moby/moby#48720](https://github.com/moby/moby/pull/48720) - `POST /networks/create` now has an `EnableIPv4` field. Setting it to `false` disables IPv4 IPAM for the network. [moby/moby#48271](https://github.com/moby/moby/pull/48271) - `GET /networks/{id}` now returns an `EnableIPv4` field showing whether the network has IPv4 IPAM enabled. [moby/moby#48271](https://github.com/moby/moby/pull/48271) - User-defined bridge networks require either IPv4 or IPv6 address assignment to be enabled. IPv4 cannot be disabled for the default bridge network (`docker0`). [moby/moby#48323](https://github.com/moby/moby/pull/48323) - `macvlan` and `ipvlan` networks can be created with address assignment disabled for IPv4, IPv6, or both address families. [moby/moby#48299](https://github.com/moby/moby/pull/48299) - IPv4 cannot be disabled for Windows or Swarm networks. [moby/moby#48278](https://github.com/moby/moby/pull/48278) - Add a way to specify which network should provide the default gateway for a container. [moby/moby#48936](https://github.com/moby/moby/pull/48936) - `POST /networks/{id}/connect` and `POST /containers/create` now accept a `GwPriority` field in `EndpointsConfig`. This value is used to determine which network endpoint provides the default gateway for the container. The endpoint with the highest priority is selected. If multiple endpoints have the same priority, endpoints are sorted lexicographically by their network name, and the one that sorts first is picked. [moby/moby#48746](https://github.com/moby/moby/pull/48746) - `GET /containers/json` now returns a `GwPriority` field in `NetworkSettings` for each network endpoint. The `GwPriority` field is used by the CLI’s new `gw-priority` option for `docker run` and `docker network connect`. [moby/moby#48746](https://github.com/moby/moby/pull/48746) - Settings for `eth0` in `--sysctl` options are no longer automatically migrated to the network endpoint. [moby/moby#48746](https://github.com/moby/moby/pull/48746) - For example, in the Docker CLI, `docker run --network mynet --sysctl net.ipv4.conf.eth0.log_martians=1 ...` is rejected. Instead, you must use `docker run --network name=mynet,driver-opt=com.docker.network.endpoint.sysctls=net.ipv4.conf.IFNAME.log_martians=1 ...` - `GET /containers/json` now returns an `ImageManifestDescriptor` field matching the same field in `/containers/{name}/json`. This field is only populated if the daemon provides a multi-platform image store. [moby/moby#49407](https://github.com/moby/moby/pull/49407) ### Removed - The Fluent logger option `fluentd-async-connect` has been deprecated in v20.10 and is now removed. [moby/moby#46114](https://github.com/moby/moby/pull/46114) - The `--time` option on `docker stop` and `docker restart` is deprecated and renamed to `--timeout`. [docker/cli#5485](https://github.com/docker/cli/pull/5485) - Go-SDK: `pkg/ioutils`: Remove `NewReaderErrWrapper` as it was never used. [moby/moby#49258](https://github.com/moby/moby/pull/49258) - Go-SDK: `pkg/ioutils`: Remove deprecated `BytesPipe`, `NewBytesPipe`, `ErrClosed`, `WriteCounter`, `NewWriteCounter`, `NewReaderErrWrapper`, `NopFlusher`. [moby/moby#49245](https://github.com/moby/moby/pull/49245) - Go-SDK: `pkg/ioutils`: Remove deprecated `NopWriter` and `NopWriteCloser`. [moby/moby#49256](https://github.com/moby/moby/pull/49256) - Go-SDK: `pkg/sysinfo`: Remove deprecated NumCPU. [moby/moby#49242](https://github.com/moby/moby/pull/49242) - Go-SDK: Remove `pkg/broadcaster`, as it was only used internally [moby/moby#49172](https://github.com/moby/moby/pull/49172)

This section details updates to the Docker API. `POST /containers/create` now allows writable cgroup mounts. `POST /build/prune` includes new prune parameters. `POST /networks/create` and `GET /networks/{id}` introduce `EnableIPv4` for network IPAM configuration. A new feature allows specifying the default gateway for a container using `GwPriority` in network connections. Sysctl settings for `eth0` are no longer automatically migrated. `GET /containers/json` now returns an `ImageManifestDescriptor` field. The Fluent logger option `fluentd-async-connect` has been removed, and the `--time` option on `docker stop` and `docker restart` is deprecated and renamed to `--timeout`. Various deprecated components in the Go-SDK have also been removed.