Information Density: containerd – Signal Evidence & AI Readability

[IMG: containerd hero logo]
An industry-standard container runtime with an emphasis on simplicity, robustness and portability
Getting started
Docs
Downloadscontainerd is graduating within the CNCF!As of February 28, 2019, containerd is officially a graduated project within the Cloud Native Computing
Foundation, following Kubernetes,
Prometheus, Envoy, and
CoreDNS. We'd like to thank the amazing
containerd community for making this all possible and we're excited for the future of the project.You can read the official announcement on the CNCF website.????
[IMG: Cloud Native Computing Foundation logo]
containerd is available as a daemon for Linux and Windows. It manages the complete container lifecycle of its host system, from image transfer and storage to container execution and supervision to low-level storage to network attachments and beyond.
[IMG: containerd architecture diagram]
FeaturesOCI Image Spec supportImage push and pull supportNetwork primitives for creation, modification, and deletion of interfacesMulti-tenant supported with CAS storage for global imagesOCI Runtime Spec support (aka runC)Container runtime and lifecycle supportManagement of network namespaces containers to join existing namespacesAdopters
[IMG: icks]
[IMG: gke]
[IMG: cloud-foundry]
[IMG: pouchcontainer]
[IMG: balena]
[IMG: linuxkit]
[IMG: docker]
[IMG: firecracker]
[IMG: kata-containers]
[IMG: instana]
[IMG: fargate]
[IMG: eks]
[IMG: bottlerocket]
[IMG: aks]
containerd is a Cloud Native Computing Foundation graduated project
[IMG: Cloud Native Computing Foundation logo]

README
Version: 2.3
Docs
Contents
Edit this page
[IMG: containerd banner light mode]
[IMG: containerd banner dark mode]
[IMG: PkgGoDev]
[IMG: Build Status]
[IMG: Nightlies]
[IMG: Go Report Card]
[IMG: CII Best Practices]
[IMG: OpenSSF Scorecard]
[IMG: Check Links]
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.
[IMG: architecture]
[H2] Announcements
[H3] 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 help with social media, community forums/groups, and google groups.We are actively inviting new
security advisors
to join the team.New subprojects 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 exp/beginner tag, for example
containerd/containerd beginner issues.
[H2] Getting Started
See our documentation on
containerd.io
:for ops and adminsnamespacesclient optionsTo get started contributing to containerd, see
CONTRIBUTING
.If you are interested in trying out containerd see our example at
Getting Started
.
[H2] Nightly builds
There are nightly builds available for download
here
.
Binaries are generated from main branch every night for Linux and Windows.Please be aware: nightly builds might have critical bugs, it’s not recommended for use in production and no support provided.
[H2] Kubernetes (k8s) CI Dashboard Group
The
k8s CI dashboard group for containerd
contains test results regarding
the health of kubernetes when run against main and a number of containerd release branches.containerd-periodics
[H2] 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 runc is described in
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
.Build requirements for developers are listed in
BUILDING
.
[H2] Supported Registries
Any registry which is compliant with the
OCI Distribution Specification
is supported by containerd.For configuring registries, see
registry host configuration documentation
[H2] Features
For a detailed overview of containerd’s core concepts and the features it supports,
please refer to the
FEATURES.MD
document.
[H3] Releases and API Stability
Please see
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
.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
.
[H4] 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
[H4] 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.
[H3] CRI
cri 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.
[IMG: cri]
[H4] CRI Status
cri is a native plugin of containerd. Since containerd 1.1, the cri plugin is built into the release binaries and enabled by default.The cri plugin has reached GA status, representing that it is:Feature completeWorks with Kubernetes 1.10 and abovePasses all
CRI validation tests
.Passes all
node e2e tests
.Passes all
e2e tests
.See results on the containerd k8s
test dashboard
[H4] Validating Your cri Setup
A Kubernetes incubator project,
cri-tools
, includes programs for exercising CRI implementations. More importantly, cri-tools includes the program critest which is used for running
CRI Validation Testing
.
[H4] CRI Guides
Installing with Ansible and KubeadmFor Non-Ansible Users, Performing a Custom Installation Using the Release Tarball and KubeadmCRI Plugin Testing GuideDebugging Pods, Containers, and Images with crictlConfiguring cri PluginsConfiguring containerd
[H3] 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 catch us in the #containerd and #containerd-dev Slack channels on Cloud Native Computing Foundation’s (CNCF) Slack - cloud-native.slack.com. Everyone is welcome to join and chat.
Get Invite to CNCF Slack.Join our next community meeting hosted on Zoom. The schedule is posted on the
CNCF Calendar
(search ‘containerd’ to filter).
[H3] Security audit
Security audits for the containerd project are hosted on our website. Please see the
security page at containerd.io
for more information.
[H3] Reporting security issues
Please follow the instructions at
containerd/project
[H2] Licenses
The containerd codebase is released under the
Apache 2.0 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/
.
[H2] Project details
containerd is the primary open source project within the broader containerd GitHub organization.
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
,Maintainers
,and
Contributing guidelinesinformation in our
containerd/project
repository.
[H2] 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
file.

README
Version: 2.2
Docs
Contents
Edit this page
[IMG: containerd banner light mode]
[IMG: containerd banner dark mode]
[IMG: PkgGoDev]
[IMG: Build Status]
[IMG: Nightlies]
[IMG: Go Report Card]
[IMG: CII Best Practices]
[IMG: OpenSSF Scorecard]
[IMG: Check Links]
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.
[IMG: architecture]
[H2] Announcements
[H3] containerd v2.0 is now released!
See
docs/containerd-2.0.md
.
[H3] 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 help with social media, community forums/groups, and google groups.We are actively inviting new
security advisors
to join the team.New subprojects 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 exp/beginner tag, for example
containerd/containerd beginner issues.
[H2] Getting Started
See our documentation on
containerd.io
:for ops and adminsnamespacesclient optionsTo get started contributing to containerd, see
CONTRIBUTING
.If you are interested in trying out containerd see our example at
Getting Started
.
[H2] Nightly builds
There are nightly builds available for download
here
.
Binaries are generated from main branch every night for Linux and Windows.Please be aware: nightly builds might have critical bugs, it’s not recommended for use in production and no support provided.
[H2] Kubernetes (k8s) CI Dashboard Group
The
k8s CI dashboard group for containerd
contains test results regarding
the health of kubernetes when run against main and a number of containerd release branches.containerd-periodics
[H2] 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 runc is described in
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
.Build requirements for developers are listed in
BUILDING
.
[H2] Supported Registries
Any registry which is compliant with the
OCI Distribution Specification
is supported by containerd.For configuring registries, see
registry host configuration documentation
[H2] Features
For a detailed overview of containerd’s core concepts and the features it supports,
please refer to the
FEATURES.MD
document.
[H3] Releases and API Stability
Please see
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
.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
.
[H4] 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
[H4] 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.
[H3] CRI
cri 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.
[IMG: cri]
[H4] CRI Status
cri is a native plugin of containerd. Since containerd 1.1, the cri plugin is built into the release binaries and enabled by default.The cri plugin has reached GA status, representing that it is:Feature completeWorks with Kubernetes 1.10 and abovePasses all
CRI validation tests
.Passes all
node e2e tests
.Passes all
e2e tests
.See results on the containerd k8s
test dashboard
[H4] Validating Your cri Setup
A Kubernetes incubator project,
cri-tools
, includes programs for exercising CRI implementations. More importantly, cri-tools includes the program critest which is used for running
CRI Validation Testing
.
[H4] CRI Guides
Installing with Ansible and KubeadmFor Non-Ansible Users, Preforming a Custom Installation Using the Release Tarball and KubeadmCRI Plugin Testing GuideDebugging Pods, Containers, and Images with crictlConfiguring cri PluginsConfiguring containerd
[H3] 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 catch us in the #containerd and #containerd-dev Slack channels on Cloud Native Computing Foundation’s (CNCF) Slack - cloud-native.slack.com. Everyone is welcome to join and chat.
Get Invite to CNCF Slack.Join our next community meeting hosted on Zoom. The schedule is posted on the
CNCF Calendar
(search ‘containerd’ to filter).
[H3] Security audit
Security audits for the containerd project are hosted on our website. Please see the
security page at containerd.io
for more information.
[H3] Reporting security issues
Please follow the instructions at
containerd/project
[H2] Licenses
The containerd codebase is released under the
Apache 2.0 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/
.
[H2] Project details
containerd is the primary open source project within the broader containerd GitHub organization.
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
,Maintainers
,and
Contributing guidelinesinformation in our
containerd/project
repository.
[H2] 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
file.

README
Version: 2.1
Docs
Contents
Edit this page
[IMG: containerd banner light mode]
[IMG: containerd banner dark mode]
[IMG: PkgGoDev]
[IMG: Build Status]
[IMG: Nightlies]
[IMG: Go Report Card]
[IMG: CII Best Practices]
[IMG: OpenSSF Scorecard]
[IMG: Check Links]
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.
[IMG: architecture]
[H2] Announcements
[H3] containerd v2.0 is now released!
See
docs/containerd-2.0.md
.
[H3] 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 help with social media, community forums/groups, and google groups.We are actively inviting new
security advisors
to join the team.New subprojects 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 exp/beginner tag, for example
containerd/containerd beginner issues.
[H2] Getting Started
See our documentation on
containerd.io
:for ops and adminsnamespacesclient optionsTo get started contributing to containerd, see
CONTRIBUTING
.If you are interested in trying out containerd see our example at
Getting Started
.
[H2] Nightly builds
There are nightly builds available for download
here
.
Binaries are generated from main branch every night for Linux and Windows.Please be aware: nightly builds might have critical bugs, it’s not recommended for use in production and no support provided.
[H2] Kubernetes (k8s) CI Dashboard Group
The
k8s CI dashboard group for containerd
contains test results regarding
the health of kubernetes when run against main and a number of containerd release branches.containerd-periodics
[H2] 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 runc is described in
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
.Build requirements for developers are listed in
BUILDING
.
[H2] Supported Registries
Any registry which is compliant with the
OCI Distribution Specification
is supported by containerd.For configuring registries, see
registry host configuration documentation
[H2] Features
For a detailed overview of containerd’s core concepts and the features it supports,
please refer to the
FEATURES.MD
document.
[H3] Releases and API Stability
Please see
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
.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
.
[H4] 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
[H4] 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.
[H3] CRI
cri 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.
[IMG: cri]
[H4] CRI Status
cri is a native plugin of containerd. Since containerd 1.1, the cri plugin is built into the release binaries and enabled by default.The cri plugin has reached GA status, representing that it is:Feature completeWorks with Kubernetes 1.10 and abovePasses all
CRI validation tests
.Passes all
node e2e tests
.Passes all
e2e tests
.See results on the containerd k8s
test dashboard
[H4] Validating Your cri Setup
A Kubernetes incubator project,
cri-tools
, includes programs for exercising CRI implementations. More importantly, cri-tools includes the program critest which is used for running
CRI Validation Testing
.
[H4] CRI Guides
Installing with Ansible and KubeadmFor Non-Ansible Users, Preforming a Custom Installation Using the Release Tarball and KubeadmCRI Plugin Testing GuideDebugging Pods, Containers, and Images with crictlConfiguring cri PluginsConfiguring containerd
[H3] 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 catch us in the #containerd and #containerd-dev Slack channels on Cloud Native Computing Foundation’s (CNCF) Slack - cloud-native.slack.com. Everyone is welcome to join and chat.
Get Invite to CNCF Slack.Join our next community meeting hosted on Zoom. The schedule is posted on the
CNCF Calendar
(search ‘containerd’ to filter).
[H3] Security audit
Security audits for the containerd project are hosted on our website. Please see the
security page at containerd.io
for more information.
[H3] Reporting security issues
Please follow the instructions at
containerd/project
[H2] Licenses
The containerd codebase is released under the
Apache 2.0 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/
.
[H2] Project details
containerd is the primary open source project within the broader containerd GitHub organization.
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
,Maintainers
,and
Contributing guidelinesinformation in our
containerd/project
repository.
[H2] 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
file.