EVOLUTION-MANAGER

Edit File: README.md

 [](https://godoc.org/github.com/containerd/containerd) [](https://github.com/containerd/containerd/actions?query=workflow%3ACI) [](https://ci.appveyor.com/project/mlaventure/containerd-3g73f?branch=master) [](https://github.com/containerd/containerd/actions?query=workflow%3ANightly) [](https://app.fossa.io/projects/git%2Bhttps%3A%2F%2Fgithub.com%2Fcontainerd%2Fcontainerd?ref=badge_shield) [](https://goreportcard.com/report/github.com/containerd/containerd) [](https://bestpractices.coreinfrastructure.org/projects/1271) 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 designed to be embedded into a larger system, rather than being used directly by developers or end-users.  ## Getting Started See our documentation on [containerd.io](https://containerd.io): * [for ops and admins](docs/ops.md) * [namespaces](docs/namespaces.md) * [client options](docs/client-opts.md) See how to build containerd from source at [BUILDING](BUILDING.md). If you are interested in trying out containerd see our example at [Getting Started](docs/getting-started.md). ## Nightly builds There are nightly builds available for download [here](https://github.com/containerd/containerd/actions?query=workflow%3ANightly). Binaries are generated from `master` branch every night for `Linux` and `Windows`. Please be aware: nightly builds might have critical bugs, it's not recommended for use in prodution 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](https://github.com/opencontainers/runc) and/or OS-specific libraries (e.g. [hcsshim](https://github.com/Microsoft/hcsshim) for Microsoft). The current required version of `runc` is described in [RUNC.md](docs/RUNC.md). 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 `criu` installed on your system. See more details in [Checkpoint and Restore](#checkpoint-and-restore). Build requirements for developers are listed in [BUILDING](BUILDING.md). ## Features ### Client containerd offers a full client package to help you integrate containerd into your platform. ```go import ( "github.com/containerd/containerd" "github.com/containerd/containerd/cio" ) func main() { client, err := containerd.New("/run/containerd/containerd.sock") defer client.Close() } ``` ### Namespaces 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: ```go 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: ```go client, err := containerd.New(address, containerd.WithDefaultNamespace("docker")) ``` ### Distribution ```go // pull an image image, err := client.Pull(context, "docker.io/library/redis:latest") // push an image err := client.Push(context, "docker.io/library/redis:latest", image.Target()) ``` ### Containers 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. ```go 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. ```go 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 builtin support for overlayfs and btrfs. ```go // pull an image and unpack it into the configured snapshotter image, err := client.Pull(context, "docker.io/library/redis:latest", 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)), ) } ``` ### Tasks Taking a container object and turning it into a runnable process on a system is done by creating a new `Task` from the container. A task represents the runnable object within containerd. ```go // 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 use 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](https://criu.org/Main_Page) installed on your machine you can checkpoint and restore containers and their tasks. This allow you to clone and/or live migrate containers to other machines. ```go // 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 `/etc/containerd/config.toml`). The string following `proxy_plugin.` 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. ``` [proxy_plugins] [proxy_plugins.customsnapshot] type = "snapshot" address = "/var/run/mysnapshotter.sock" ``` See [PLUGINS.md](PLUGINS.md) for how to create plugins ### Releases and API Stability Please see [RELEASES.md](RELEASES.md) 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](https://github.com/containerd/containerd/releases), as well as auto-published to the [cri-containerd-release storage bucket](https://console.cloud.google.com/storage/browser/cri-containerd-release?pli=1). 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](https://launchpad.net/ubuntu/bionic/+package/containerd). #### 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 `.bashrc`, or manually like: ``` $ source ./contrib/autocomplete/ctr ``` #### Distribution of `ctr` autocomplete for bash and zsh For bash, copy the `contrib/autocomplete/ctr` script into `/etc/bash_completion.d/` and rename it to `ctr`. The `zsh_autocomplete` file is also available and can be used similarly for zsh users. Provide documentation to users to `source` 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. ### Communication 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 we have a community slack with a #containerd channel that everyone is welcome to join and chat about development. **Slack:** Catch us in the #containerd and #containerd-dev channels on dockercommunity.slack.com. [Click here for an invite to docker community slack.](https://dockr.ly/slack) ### Security audit A third party security audit was performed by Cure53 in 4Q2018; the [full report](docs/SECURITY_AUDIT.pdf) is available in our docs/ directory. ### Reporting security issues __If you are reporting a security issue, please reach out discreetly at security@containerd.io__. ## Licenses The containerd codebase is released under the [Apache 2.0 license](LICENSE). The README.md 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 http://creativecommons.org/licenses/by/4.0/. ## 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 `project` repository commonly for all containerd projects. Please find all these core project documents, including the: * [Project governance](https://github.com/containerd/project/blob/master/GOVERNANCE.md), * [Maintainers](https://github.com/containerd/project/blob/master/MAINTAINERS), * and [Contributing guidelines](https://github.com/containerd/project/blob/master/CONTRIBUTING.md) information in our [`containerd/project`](https://github.com/containerd/project) repository. ## Adoption Interested to see who is using containerd? Are you using containerd in a project? Please add yourself via pull request to our [ADOPTERS.md](./ADOPTERS.md) file.