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containerd is an industry-standard container runtime with an emphasis on simplicity, robustness and portability. It is available as a daemon for Linux and Windows, which can manage the complete container lifecycle of its host system: image transfer and storage, container execution and supervision, low-level storage and network attachments, etc.

containerd is a member of CNCF with 'graduated' status.

containerd is designed to be embedded into a larger system, rather than being used directly by developers or end-users.


Now Recruiting

We are a large inclusive OSS project that is welcoming help of any kind shape or form: * Documentation help is needed to make the product easier to consume and extend. * We need OSS community outreach / organizing help to get the word out; manage and create messaging and educational content; and to help with social media, community forums/groups, and google groups. * We are actively inviting new security advisors to join the team. * New sub-projects are being created, core and non-core that could use additional development help. * Each of the containerd projects has a list of issues currently being worked on or that need help resolving. - If the issue has not already been assigned to someone, or has not made recent progress and you are interested, please inquire. - If you are interested in starting with a smaller / beginner level issue, look for issues with an

tag, for example containerd/containerd beginner issues.

Getting Started

See our documentation on * for ops and admins * namespaces * client options

See how to build containerd from source at BUILDING.

If you are interested in trying out containerd see our example at Getting Started.

Nightly builds

There are nightly builds available for download here. Binaries are generated from

branch every night for

Please be aware: nightly builds might have critical bugs, it's not recommended for use in production and no support provided.

Runtime Requirements

Runtime requirements for containerd are very minimal. Most interactions with the Linux and Windows container feature sets are handled via runc and/or OS-specific libraries (e.g. hcsshim for Microsoft). The current required version of

is described in

There are specific features used by containerd core code and snapshotters that will require a minimum kernel version on Linux. With the understood caveat of distro kernel versioning, a reasonable starting point for Linux is a minimum 4.x kernel version.

The overlay filesystem snapshotter, used by default, uses features that were finalized in the 4.x kernel series. If you choose to use btrfs, there may be more flexibility in kernel version (minimum recommended is 3.18), but will require the btrfs kernel module and btrfs tools to be installed on your Linux distribution.

To use Linux checkpoint and restore features, you will need

installed on your system. See more details in Checkpoint and Restore.

Build requirements for developers are listed in BUILDING.

Supported Registries

Any registry which is compliant with the OCI Distribution Specification is supported by containerd.

For configuring registries, see registry host configuration documentation



containerd offers a full client package to help you integrate containerd into your platform.

import (

"" "" "" )

func main() { client, err := containerd.New("/run/containerd/containerd.sock") defer client.Close() }


Namespaces allow multiple consumers to use the same containerd without conflicting with each other. It has the benefit of sharing content but still having separation with containers and images.

To set a namespace for requests to the API:

context = context.Background()
// create a context for docker
docker = namespaces.WithNamespace(context, "docker")

containerd, err := client.NewContainer(docker, "id")

To set a default namespace on the client:

client, err := containerd.New(address, containerd.WithDefaultNamespace("docker"))


// pull an image
image, err := client.Pull(context, "")

// push an image err := client.Push(context, "", image.Target())


In containerd, a container is a metadata object. Resources such as an OCI runtime specification, image, root filesystem, and other metadata can be attached to a container.

redis, err := client.NewContainer(context, "redis-master")
defer redis.Delete(context)

OCI Runtime Specification

containerd fully supports the OCI runtime specification for running containers. We have built in functions to help you generate runtime specifications based on images as well as custom parameters.

You can specify options when creating a container about how to modify the specification.

redis, err := client.NewContainer(context, "redis-master", containerd.WithNewSpec(oci.WithImageConfig(image)))

Root Filesystems

containerd allows you to use overlay or snapshot filesystems with your containers. It comes with built in support for overlayfs and btrfs.

// pull an image and unpack it into the configured snapshotter
image, err := client.Pull(context, "", containerd.WithPullUnpack)

// allocate a new RW root filesystem for a container based on the image redis, err := client.NewContainer(context, "redis-master", containerd.WithNewSnapshot("redis-rootfs", image), containerd.WithNewSpec(oci.WithImageConfig(image)), )

// use a readonly filesystem with multiple containers for i := 0; i < 10; i++ { id := fmt.Sprintf("id-%s", i) container, err := client.NewContainer(ctx, id, containerd.WithNewSnapshotView(id, image), containerd.WithNewSpec(oci.WithImageConfig(image)), ) }


Taking a container object and turning it into a runnable process on a system is done by creating a new

from the container. A task represents the runnable object within containerd.
// create a new task
task, err := redis.NewTask(context, cio.NewCreator(cio.WithStdio))
defer task.Delete(context)

// the task is now running and has a pid that can be used to setup networking // or other runtime settings outside of containerd pid := task.Pid()

// start the redis-server process inside the container err := task.Start(context)

// wait for the task to exit and get the exit status status, err := task.Wait(context)

Checkpoint and Restore

If you have criu installed on your machine you can checkpoint and restore containers and their tasks. This allows you to clone and/or live migrate containers to other machines.

// checkpoint the task then push it to a registry
checkpoint, err := task.Checkpoint(context)

err := client.Push(context, "myregistry/checkpoints/redis:master", checkpoint)

// on a new machine pull the checkpoint and restore the redis container checkpoint, err := client.Pull(context, "myregistry/checkpoints/redis:master")

redis, err = client.NewContainer(context, "redis-master", containerd.WithNewSnapshot("redis-rootfs", checkpoint)) defer container.Delete(context)

task, err = redis.NewTask(context, cio.NewCreator(cio.WithStdio), containerd.WithTaskCheckpoint(checkpoint)) defer task.Delete(context)

err := task.Start(context)

Snapshot Plugins

In addition to the built-in Snapshot plugins in containerd, additional external plugins can be configured using GRPC. An external plugin is made available using the configured name and appears as a plugin alongside the built-in ones.

To add an external snapshot plugin, add the plugin to containerd's config file (by default at

). The string following
will be used as the name of the snapshotter and the address should refer to a socket with a GRPC listener serving containerd's Snapshot GRPC API. Remember to restart containerd for any configuration changes to take effect.
    type = "snapshot"
    address =  "/var/run/mysnapshotter.sock"

See for how to create plugins

Releases and API Stability

Please see for details on versioning and stability of containerd components.

Downloadable 64-bit Intel/AMD binaries of all official releases are available on our releases page.

For other architectures and distribution support, you will find that many Linux distributions package their own containerd and provide it across several architectures, such as Canonical's Ubuntu packaging.

Enabling command auto-completion

Starting with containerd 1.4, the urfave client feature for auto-creation of bash and zsh autocompletion data is enabled. To use the autocomplete feature in a bash shell for example, source the autocomplete/ctr file in your

, or manually like:
$ source ./contrib/autocomplete/ctr

Distribution of
autocomplete for bash and zsh

For bash, copy the

script into
and rename it to
. The
file is also available and can be used similarly for zsh users.

Provide documentation to users to

this file into their shell if you don't place the autocomplete file in a location where it is automatically loaded for the user's shell environment.


is a containerd plugin implementation of the Kubernetes container runtime interface (CRI). With it, you are able to use containerd as the container runtime for a Kubernetes cluster.


CRI Status

is a native plugin of containerd. Since containerd 1.1, the cri plugin is built into the release binaries and enabled by default.

Note: As of containerd 1.5, the

plugin is merged into the containerd/containerd repo. For example, the source code previously stored under
was moved to


plugin has reached GA status, representing that it is: * Feature complete * Works with Kubernetes 1.10 and above * Passes all CRI validation tests. * Passes all node e2e tests. * Passes all e2e tests.

See results on the containerd k8s test dashboard

Validating Your

A Kubernetes incubator project, cri-tools, includes programs for exercising CRI implementations. More importantly, cri-tools includes the program

which is used for running CRI Validation Testing.

CRI Guides


For async communication and long running discussions please use issues and pull requests on the github repo. This will be the best place to discuss design and implementation.

For sync communication catch us in the

slack channels on Cloud Native Computing Foundation's (CNCF) slack -
. Everyone is welcome to join and chat. Get Invite to CNCF slack.

Security audit

A third party security audit was performed by Cure53 in 4Q2018; the full report is available in our docs/ directory.

Reporting security issues

If you are reporting a security issue, please reach out discreetly at [email protected].


The containerd codebase is released under the Apache 2.0 license. The file, and files in the "docs" folder are licensed under the Creative Commons Attribution 4.0 International License. You may obtain a copy of the license, titled CC-BY-4.0, at

Project details

containerd is the primary open source project within the broader containerd GitHub repository. However, all projects within the repo have common maintainership, governance, and contributing guidelines which are stored in a

repository commonly for all containerd projects.

Please find all these core project documents, including the: * Project governance, * Maintainers, * and Contributing guidelines

information in our



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