github.com/containers/podman/v2@v2.2.2-0.20210501105131-c1e07d070c4c/README.md (about) 1 ![PODMAN logo](logo/podman-logo-source.svg) 2 3 # Podman: A tool for managing OCI containers and pods 4 5 Podman (the POD MANager) is a tool for managing containers and images, volumes mounted into those containers, and pods made from groups of containers. 6 Podman is based on libpod, a library for container lifecycle management that is also contained in this repository. The libpod library provides APIs for managing containers, pods, container images, and volumes. 7 8 * [Latest Version: 2.1.1](https://github.com/containers/podman/releases/latest) 9 * Latest Remote client for Windows 10 * Latest Remote client for MacOs 11 * Latest Static Remote client for Linux 12 13 * Continuous Integration: [![Build Status](https://api.cirrus-ci.com/github/containers/podman.svg)](https://cirrus-ci.com/github/containers/podman/master) 14 * [GoDoc: ![GoDoc](https://godoc.org/github.com/containers/podman/libpod?status.svg)](https://godoc.org/github.com/containers/podman/libpod) 15 16 ## Overview and scope 17 18 At a high level, the scope of Podman and libpod is the following: 19 20 * Support for multiple container image formats, including OCI and Docker images. 21 * Full management of those images, including pulling from various sources (including trust and verification), creating (built via Containerfile or Dockerfile or committed from a container), and pushing to registries and other storage backends. 22 * Full management of container lifecycle, including creation (both from an image and from an exploded root filesystem), running, checkpointing and restoring (via CRIU), and removal. 23 * Support for pods, groups of containers that share resources and are managed together. 24 * Support for running containers and pods without root or other elevated privileges. 25 * Resource isolation of containers and pods. 26 * Support for a Docker-compatible CLI interface. 27 * No manager daemon, for improved security and lower resource utilization at idle. 28 * Support for a REST API providing both a Docker-compatible interface and an improved interface exposing advanced Podman functionality. 29 * In the future, integration with [CRI-O](https://github.com/cri-o/cri-o) to share containers and backend code. 30 31 Podman presently only supports running containers on Linux. However, we are building a remote client which can run on Windows and OS X and manage Podman containers on a Linux system via the REST API using SSH tunneling. 32 33 ## Roadmap 34 35 1. Further improvements to the REST API, with a focus on bugfixes and implementing missing functionality 36 1. Integrate libpod into [CRI-O](https://github.com/cri-o/cri-o) to replace its existing container management backend 37 1. Improvements on rootless containers, with a focus on improving the user experience and exposing presently-unavailable features when possible 38 39 ## Communications 40 41 If you think you've identified a security issue in the project, please *DO NOT* report the issue publicly via the Github issue tracker, mailing list, or IRC. 42 Instead, send an email with as many details as possible to `security@lists.podman.io`. This is a private mailing list for the core maintainers. 43 44 For general questions and discussion, please use the 45 IRC `#podman` channel on `irc.freenode.net`. 46 47 For discussions around issues/bugs and features, you can use the GitHub 48 [issues](https://github.com/containers/podman/issues) 49 and 50 [PRs](https://github.com/containers/podman/pulls) 51 tracking system. 52 53 There is also a [mailing list](https://lists.podman.io/archives/) at `lists.podman.io`. 54 You can subscribe by sending a message to `podman-join@lists.podman.io` with the subject `subscribe`. 55 56 ## Rootless 57 Podman can be easily run as a normal user, without requiring a setuid binary. 58 When run without root, Podman containers use user namespaces to set root in the container to the user running Podman. 59 Rootless Podman runs locked-down containers with no privileges that the user running the container does not have. 60 Some of these restrictions can be lifted (via `--privileged`, for example), but rootless containers will never have more privileges than the user that launched them. 61 If you run Podman as your user and mount in `/etc/passwd` from the host, you still won't be able to change it, since your user doesn't have permission to do so. 62 63 Almost all normal Podman functionality is available, though there are some [shortcomings](https://github.com/containers/podman/blob/master/rootless.md). 64 Any recent Podman release should be able to run rootless without any additional configuration, though your operating system may require some additional configuration detailed in the [install guide](https://github.com/containers/podman/blob/master/install.md). 65 66 A little configuration by an administrator is required before rootless Podman can be used, the necessary setup is documented [here](https://github.com/containers/podman/blob/master/docs/tutorials/rootless_tutorial.md). 67 68 ## Out of scope 69 70 * Specialized signing and pushing of images to various storage backends. 71 See [Skopeo](https://github.com/containers/skopeo/) for those tasks. 72 * Support for the Kubernetes CRI interface for container management. 73 The [CRI-O](https://github.com/cri-o/cri-o) daemon specializes in that. 74 * Supporting `docker-compose`. We believe that Kubernetes is the defacto 75 standard for composing Pods and for orchestrating containers, making 76 Kubernetes YAML a defacto standard file format. Hence, Podman allows the 77 creation and execution of Pods from a Kubernetes YAML file (see 78 [podman-play-kube](https://github.com/containers/podman/blob/master/docs/source/markdown/podman-play-kube.1.md)). 79 Podman can also generate Kubernetes YAML based on a container or Pod (see 80 [podman-generate-kube](https://github.com/containers/podman/blob/master/docs/source/markdown/podman-generate-kube.1.md)), 81 which allows for an easy transition from a local development environment 82 to a production Kubernetes cluster. If Kubernetes does not fit your requirements, 83 there are other third-party tools that support the docker-compose format such as 84 [kompose](https://github.com/kubernetes/kompose/) and 85 [podman-compose](https://github.com/muayyad-alsadi/podman-compose) 86 that might be appropriate for your environment. This situation may change with 87 the addition of the REST API. 88 89 ## OCI Projects Plans 90 91 The plan is to use OCI projects and best of breed libraries for different aspects: 92 - Runtime: We use the [OCI runtime tools](https://github.com/opencontainers/runtime-tools) to generate OCI runtime configurations that can be used with any OCI-compliant runtime, like [crun](https://github.com/containers/crun/) and [runc](https://github.com/opencontainers/runc/). 93 - Images: Image management uses the [containers/image](https://github.com/containers/image) library. 94 - Storage: Container and image storage is managed by [containers/storage](https://github.com/containers/storage). 95 - Networking: Networking support through use of [CNI](https://github.com/containernetworking/cni). 96 - Builds: Builds are supported via [Buildah](https://github.com/containers/buildah). 97 - Conmon: [Conmon](https://github.com/containers/conmon) is a tool for monitoring OCI runtimes, used by both Podman and CRI-O. 98 - Seccomp: A unified [Seccomp](https://github.com/seccomp/containers-golang) policy for Podman, Buildah, and CRI-O. 99 100 ## Podman Information for Developers 101 102 For blogs, release announcements and more, please checkout the [podman.io](https://podman.io) website! 103 104 **[Installation notes](install.md)** 105 Information on how to install Podman in your environment. 106 107 **[OCI Hooks Support](pkg/hooks/README.md)** 108 Information on how Podman configures [OCI Hooks][spec-hooks] to run when launching a container. 109 110 **[Podman API](http://docs.podman.io/en/latest/_static/api.html)** 111 Documentation on the Podman REST API. 112 113 **[Podman Commands](https://podman.readthedocs.io/en/latest/Commands.html)** 114 A list of the Podman commands with links to their man pages and in many cases videos 115 showing the commands in use. 116 117 **[Podman Troubleshooting Guide](troubleshooting.md)** 118 A list of common issues and solutions for Podman. 119 120 **[Podman Usage Transfer](transfer.md)** 121 Useful information for ops and dev transfer as it relates to infrastructure that utilizes Podman. This page 122 includes tables showing Docker commands and their Podman equivalent commands. 123 124 **[Tutorials](docs/tutorials)** 125 Tutorials on using Podman. 126 127 **[Remote Client](https://github.com/containers/podman/blob/master/docs/tutorials/remote_client.md)** 128 A brief how-to on using the Podman remote-client. 129 130 **[Basic Setup and Use of Podman in a Rootless environment](https://github.com/containers/podman/blob/master/docs/tutorials/rootless_tutorial.md)** 131 A tutorial showing the setup and configuration necessary to run Rootless Podman. 132 133 **[Release Notes](RELEASE_NOTES.md)** 134 Release notes for recent Podman versions. 135 136 **[Contributing](CONTRIBUTING.md)** 137 Information about contributing to this project. 138 139 [spec-hooks]: https://github.com/opencontainers/runtime-spec/blob/v1.0.2/config.md#posix-platform-hooks 140 141 ## Buildah and Podman relationship 142 143 Buildah and Podman are two complementary open-source projects that are 144 available on most Linux platforms and both projects reside at 145 [GitHub.com](https://github.com) with Buildah 146 [here](https://github.com/containers/buildah) and Podman 147 [here](https://github.com/containers/podman). Both, Buildah and Podman are 148 command line tools that work on Open Container Initiative (OCI) images and 149 containers. The two projects differentiate in their specialization. 150 151 Buildah specializes in building OCI images. Buildah's commands replicate all 152 of the commands that are found in a Dockerfile. This allows building images 153 with and without Dockerfiles while not requiring any root privileges. 154 Buildah’s ultimate goal is to provide a lower-level coreutils interface to 155 build images. The flexibility of building images without Dockerfiles allows 156 for the integration of other scripting languages into the build process. 157 Buildah follows a simple fork-exec model and does not run as a daemon 158 but it is based on a comprehensive API in golang, which can be vendored 159 into other tools. 160 161 Podman specializes in all of the commands and functions that help you to maintain and modify 162 OCI images, such as pulling and tagging. It also allows you to create, run, and maintain those containers 163 created from those images. For building container images via Dockerfiles, Podman uses Buildah's 164 golang API and can be installed independently from Buildah. 165 166 A major difference between Podman and Buildah is their concept of a container. Podman 167 allows users to create "traditional containers" where the intent of these containers is 168 to be long lived. While Buildah containers are really just created to allow content 169 to be added back to the container image. An easy way to think of it is the 170 `buildah run` command emulates the RUN command in a Dockerfile while the `podman run` 171 command emulates the `docker run` command in functionality. Because of this and their underlying 172 storage differences, you can not see Podman containers from within Buildah or vice versa. 173 174 In short, Buildah is an efficient way to create OCI images while Podman allows 175 you to manage and maintain those images and containers in a production environment using 176 familiar container cli commands. For more details, see the 177 [Container Tools Guide](https://github.com/containers/buildah/tree/master/docs/containertools). 178 179 ## Podman Legacy API (Varlink) 180 Podman offers a [Varlink-based API](https://github.com/containers/podman/blob/master/docs/tutorials/varlink_remote_client.md) 181 for remote management of containers. However, this API has been deprecated by the REST API. 182 Varlink support is in maintenance mode, and will be removed in a future release. 183 For more details, you can see [this blog](https://podman.io/blogs/2020/01/17/podman-new-api.html). 184 185 ## Static Binary Builds 186 The Cirrus CI integration within this repository contains a `static_build` job 187 which produces a static Podman binary for testing purposes. Please note that 188 this binary is not officially supported with respect to feature-completeness 189 and functionality and should be only used for testing.