Docker Engine 27.0 release notes

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This page describes the latest changes, additions, known issues, and fixes for Docker Engine version 27.0.

For more information about:

27.0.2

2024-06-27

For a full list of pull requests and changes in this release, refer to the relevant GitHub milestones:

Bug fixes and enhancements

Removed

  • api/types: deprecate ContainerJSONBase.Node field and ContainerNode type. These definitions were used by the standalone ("classic") Swarm API, but never implemented in the Docker Engine itself. moby/moby#48055

27.0.1

2024-06-24

For a full list of pull requests and changes in this release, refer to the relevant GitHub milestones:

New

  • containerd image store: Add --platform flag to docker image push and improve the default behavior when not all platforms of the multi-platform image are available locally. docker/cli#4984, moby/moby#47679
  • Add support to docker stack deploy for driver_opts in a service's networks. docker/cli#5125
  • Consider additional /usr/local/libexec and /usr/libexec paths when looking up the userland proxy binaries by a name with a docker- prefix. moby/moby#47804

Bug fixes and enhancements

  • *client.Client instances are now always safe for concurrent use by multiple goroutines. Previously, this could lead to data races when the WithAPIVersionNegotiation() option is used. moby/moby#47961
  • Fix a bug causing the Docker CLI to leak Unix sockets in $TMPDIR in some cases. docker/cli#5146
  • Don't ignore a custom seccomp profile when used in conjunction with --privileged. moby/moby#47500
  • rootless: overlay2: support native overlay diff when using rootless-mode with Linux kernel version 5.11 and later. moby/moby#47605
  • Fix the StartInterval default value of healthcheck to reflect the documented value of 5s. moby/moby#47799
  • Fix docker save and docker load not ending on the daemon side when the operation was cancelled by the user, for example with Ctrl+C. moby/moby#47629
  • The StartedAt property of containers is now recorded before container startup, guaranteeing that the StartedAt is always before FinishedAt. moby/moby#47003
  • The internal DNS resolver used by Windows containers on Windows now forwards requests to external DNS servers by default. This enables nslookup to resolve external hostnames. This behaviour can be disabled via daemon.json, using "features": { "windows-dns-proxy": false }. The configuration option will be removed in a future release. moby/moby#47826
  • Print a warning when the CLI does not have permissions to read the configuration file. docker/cli#5077
  • Fix a goroutine and file-descriptor leak on container attach. moby/moby#45052
  • Clear the networking state of all stopped or dead containers during daemon start-up. moby/moby#47984
  • Write volume options JSON atomically to avoid "invalid JSON" errors after system crash. moby/moby#48034
  • Allow multiple macvlan networks with the same parent. moby/moby#47318
  • Allow BuildKit to be used on Windows daemons that advertise it. docker/cli#5178

Networking

  • Allow sysctls to be set per-interface during container creation and network connection. moby/moby#47686
    • In a future release, this will be the only way to set per-interface sysctl options. For example, on the command line in a docker run command,--network mynet --sysctl net.ipv4.conf.eth0.log_martians=1 will be rejected. Instead, you must use --network name=mynet,driver-opt=com.docker.network.endpoint.sysctls=net.ipv4.conf.IFNAME.log_martians=1.

IPv6

  • ip6tables is no longer experimental. You may remove the experimental configuration option and continue to use IPv6, if it is not required by any other features.
  • ip6tables is now enabled for Linux bridge networks by default. moby/moby#47747
    • This makes IPv4 and IPv6 behaviors consistent with each other, and reduces the risk that IPv6-enabled containers are inadvertently exposed to the network.
    • There is no impact if you are running Docker Engine with ip6tables enabled (new default).
    • If you are using an IPv6-enabled bridge network without ip6tables, this is likely a breaking change. Only published container ports (-p or --publish) are accessible from outside the Docker bridge network, and outgoing connections masquerade as the host.
    • To restore the behavior of earlier releases, no ip6tables at all, set "ip6tables": false in daemon.json, or use the CLI option --ip6tables=false. Alternatively, leave ip6tables enabled, publish ports, and enable direct routing.
    • With ip6tables enabled, if ip6tables is not functional on your host, Docker Engine will start but it will not be possible to create an IPv6-enabled network.

IPv6 network configuration improvements

  • A Unique Local Address (ULA) base prefix is automatically added to default-address-pools if this parameter wasn't manually configured, or if it contains no IPv6 prefixes. moby/moby#47853
    • Prior to this release, to create an IPv6-enabled network it was necessary to use the --subnet option to specify an IPv6 subnet, or add IPv6 ranges to default-address-pools in daemon.json.
    • Starting in this release, when a bridge network is created with --ipv6 and no IPv6 subnet is defined by those options, an IPv6 Unique Local Address (ULA) base prefix is used.
    • The ULA prefix is derived from the Engine host ID such that it's unique across hosts and over time.
  • IPv6 address pools of any size can now be added to default-address-pools. moby/moby#47768
  • IPv6 can now be enabled by default on all custom bridge networks using "default-network-opts": { "bridge": {"com.docker.network.enable_ipv6": "true"}} in daemon.json, or dockerd --default-network-opt=bridge=com.docker.network.enable_ipv6=trueon the comand line. moby/moby#47867
  • Direct routing for IPv6 networks, with ip6tables enabled. moby/moby#47871
    • Added bridge driver option com.docker.network.bridge.gateway_mode_ipv6=<nat|routed>.
    • The default behavior, nat, is unchanged from previous releases running with ip6tables enabled. NAT and masquerading rules are set up for each published container port.
    • When set to routed, no NAT or masquerading rules are configured for published ports. This enables direct IPv6 access to the container, if the host's network can route packets for the container's address to the host. Published ports will be opened in the container's firewall.
    • When a port mapping only applies to routed mode, only addresses 0.0.0.0 or :: are allowed and a host port must not be given.
    • Note that published container ports, in nat or routed mode, are accessible from any remote address if routing is set up in the network, unless the Docker host's firewall has additional restrictions. For example: docker network create --ipv6 -o com.docker.network.bridge.gateway_mode_ipv6=routed mynet.
    • The option com.docker.network.bridge.gateway_mode_ipv4=<nat|routed> is also available, with the same behavior but for IPv4.
  • If firewalld is running on the host, Docker creates policy docker-forwarding to allow forwarding from any zone to the docker zone. This makes it possible to configure a bridge network with a routable IPv6 address, and no NAT or masquerading. moby/moby#47745
  • When a port is published with no host port specified, or a host port range is given, the same port will be allocated for IPv4 and IPv6. moby/moby#47871
    • For example -p 80 will result in the same ephemeral port being allocated for 0.0.0.0 and ::, and -p 8080-8083:80 will pick the same port from the range for both address families.
    • Similarly, ports published to specific addresses will be allocated the same port. For example, -p 127.0.0.1::80 -p '[::1]::80'.
    • If no port is available on all required addresses, container creation will fail.
  • Environment variable DOCKER_ALLOW_IPV6_ON_IPV4_INTERFACE, introduced in release 26.1.1, no longer has any effect. moby/moby#47963
    • If IPv6 could not be disabled on an interface because of a read-only /proc/sys/net, the environment variable allowed the container to start anyway.
    • In this release, if IPv4 cannot be disabled for an interface, IPv6 can be explicitly enabled for the network simply by using --ipv6 when creating it. Other workarounds are to configure the OS to disable IPv6 by default on new interfaces, mount /proc/sys/net read-write, or use a kernel with no IPv6 support.
  • For IPv6-enabled bridge networks, do not attempt to replace the bridge's kernel-assigned link local address with fe80::1. moby/moby#47787

Removed

  • Deprecate experimental GraphDriver plugins. moby/moby#48050, docker/cli#5172
  • pkg/archive: deprecate NewTempArchive and TempArchive. These types were only used in tests and will be removed in the next release. moby/moby#48002
  • pkg/archive: deprecate CanonicalTarNameForPath moby/moby#48001
  • Deprecate pkg/dmesg. This package was no longer used, and will be removed in the next release. moby/moby#47999
  • Deprecate pkg/stringid.ValidateID and pkg/stringid.IsShortID moby/moby#47995
  • runconfig: deprecate SetDefaultNetModeIfBlank and move ContainerConfigWrapper to api/types/container moby/moby#48007
  • runconfig: deprecate DefaultDaemonNetworkMode and move to daemon/network moby/moby#48008
  • runconfig: deprecate opts.ConvertKVStringsToMap. This utility is no longer used, and will be removed in the next release. moby/moby#48016
  • runconfig: deprecate IsPreDefinedNetwork. moby/moby#48011

API

  • containerd image store: POST /images/{name}/push now supports a platform parameter (JSON encoded OCI Platform type) that allows selecting a specific platform-manifest from the multi-platform image. This is experimental and may change in future API versions. moby/moby#47679
  • POST /services/create and POST /services/{id}/update now support OomScoreAdj. moby/moby#47950
  • ContainerList api returns container annotations. moby/moby#47866
  • POST /containers/create and POST /services/create now take Options as part of HostConfig.Mounts.TmpfsOptions allowing to set options for tmpfs mounts. moby/moby#46809
  • The Healthcheck.StartInterval property is now correctly ignored when updating a Swarm service using API versions less than v1.44. moby/moby#47991
  • GET /events now supports image create event that is emitted when a new image is built regardless if it was tagged or not. moby/moby#47929
  • GET /info now includes a Containerd field containing information about the location of the containerd API socket and containerd namespaces used by the daemon to run containers and plugins. moby/moby#47239
  • Deprecate non-standard (config) fields in image inspect output. The Config field returned by this endpoint (used for docker image inspect) returned additional fields that are not part of the image's configuration and not part of the Docker Image Spec and the OCI Image Spec. These fields are never set (and always return the default value for the type), but are not omitted in the response when left empty. As these fields were not intended to be part of the image configuration response, they are deprecated, and will be removed in the future API versions.
  • Deprecate the daemon flag --api-cors-header and the corresponding daemon.json configuration option. These will be removed in the next major release. moby/moby#45313

The following deprecated fields are currently included in the API response, but are not part of the underlying image's Config: moby/moby#47941

  • Hostname
  • Domainname
  • AttachStdin
  • AttachStdout
  • AttachStderr
  • Tty
  • OpenStdin
  • StdinOnce
  • Image
  • NetworkDisabled (already omitted unless set)
  • MacAddress (already omitted unless set)
  • StopTimeout (already omitted unless set)

Go SDK changes

  • Client API callback for the following functions now require a context parameter. moby/moby#47536
    • client.RequestPrivilegeFunc
    • client.ImageSearchOptions.AcceptPermissionsFunc
    • image.ImportOptions.PrivilegeFunc
  • Remove deprecated aliases for Image types. moby/moby#47900
    • ImageImportOptions
    • ImageCreateOptions
    • ImagePullOptions
    • ImagePushOptions
    • ImageListOptions
    • ImageRemoveOptions
  • Introduce Ulimit type alias for github.com/docker/go-units.Ulimit. The Ulimit type as used in the API is defined in a Go module that will transition to a new location in future. A type alias is added to reduce the friction that comes with moving the type to a new location. The alias makes sure that existing code continues to work, but its definition may change in future. Users are recommended to use this alias instead of the units.Ulimit directly. moby/moby#48023

Move and rename types, changing their import paths and exported names. moby/moby#47936, moby/moby#47873, moby/moby#47887, moby/moby#47882, moby/moby#47921, moby/moby#48040

  • Move the following types to api/types/container:
    • BlkioStatEntry
    • BlkioStats
    • CPUStats
    • CPUUsage
    • ContainerExecInspect
    • ContainerPathStat
    • ContainerStats
    • ContainersPruneReport
    • CopyToContainerOptions
    • ExecConfig
    • ExecStartCheck
    • MemoryStats
    • NetworkStats
    • PidsStats
    • StatsJSON
    • Stats
    • StorageStats
    • ThrottlingData
  • Move the following types to api/types/image:
    • ImagesPruneReport
    • ImageImportSource
    • ImageLoadResponse
  • Move the ExecStartOptions type to api/types/backend.
  • Move the VolumesPruneReport type to api/types/volume.
  • Move the EventsOptions type to api/types/events.
  • Move the ImageSearchOptions type to api/types/registry.
  • Drop Network prefix and move the following types to api/types/network:
    • NetworkCreateResponse
    • NetworkConnect
    • NetworkDisconnect
    • NetworkInspectOptions
    • EndpointResource
    • NetworkListOptions
    • NetworkCreateOptions
    • NetworkCreateRequest
    • NetworksPruneReport
  • Move NetworkResource to api/types/network.

Packaging updates

27.0.0

There's no 27.0.0 release due to a mistake during the pre-release of 27.0.0-rc.1 on GitHub which resulted in the v27.0.0 tag being created. Unfortunately the tag was already picked up by the Go Module Mirror so it's not possible to cleanly change the v27.0.0. To workaround this, the 27.0.1 will be the first release of the 27.0.