github.com/hanks177/podman/v4@v4.1.3-0.20220613032544-16d90015bc83/README.md (about) 1  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 runs containers on Linux, but can also be used on Mac and Windows systems using a Podman-managed virtual machine. 7 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. 8 9 * [Latest Version: 4.1.0](https://github.com/containers/podman/releases/tag/v4.1.0) 10 * Latest Remote client for Windows 11 * Latest Remote client for macOS 12 * Latest Static Remote client for Linux 13 14 * Continuous Integration: [](https://cirrus-ci.com/github/containers/podman/master) 15 * [GoDoc: ](https://godoc.org/github.com/containers/podman/libpod) 16 17 ## Overview and scope 18 19 At a high level, the scope of Podman and libpod is the following: 20 21 * Support for multiple container image formats, including OCI and Docker images. 22 * 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. 23 * 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. 24 * Full management of container networking, using CNI, Netavark, and slirp4netns 25 * Support for pods, groups of containers that share resources and are managed together. 26 * Support for running containers and pods without root or other elevated privileges. 27 * Resource isolation of containers and pods. 28 * Support for a Docker-compatible CLI interface, which can both run containers locally and on remote systems. 29 * No manager daemon, for improved security and lower resource utilization at idle. 30 * Support for a REST API providing both a Docker-compatible interface and an improved interface exposing advanced Podman functionality. 31 * Support for running on Windows and Mac via virtual machines run by `podman machine`. 32 33 ## Roadmap 34 35 1. A fully-featured GUI frontend for `podman machine` 36 1. Further improvements to `podman generate kube` and `podman play kube` 37 1. Improvements to Pods, including the addition of pod-level resource limits 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 Podman's 45 [channels](https://podman.io/community/#slack-irc-matrix-and-discord). 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/main/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/main/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/main/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 75 ## OCI Projects Plans 76 77 Podman uses OCI projects and best of breed libraries for different aspects: 78 - 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/). 79 - Images: Image management uses the [containers/image](https://github.com/containers/image) library. 80 - Storage: Container and image storage is managed by [containers/storage](https://github.com/containers/storage). 81 - Networking: Networking support through use of [Netavark](https://github.com/containers/netavark) and [Aardvark](https://github.com/containers/aardvark-dns). Support for [CNI](https://github.com/containernetworking/cni) is also available. Rootless networking is handled via [slirp4netns](https://github.com/rootless-containers/slirp4netns). 82 - Builds: Builds are supported via [Buildah](https://github.com/containers/buildah). 83 - Conmon: [Conmon](https://github.com/containers/conmon) is a tool for monitoring OCI runtimes, used by both Podman and CRI-O. 84 - Seccomp: A unified [Seccomp](https://github.com/containers/common/blob/main/pkg/seccomp/seccomp.json) policy for Podman, Buildah, and CRI-O. 85 86 ## Podman Information for Developers 87 88 For blogs, release announcements and more, please checkout the [podman.io](https://podman.io) website! 89 90 **[Installation notes](install.md)** 91 Information on how to install Podman in your environment. 92 93 **[OCI Hooks Support](pkg/hooks/README.md)** 94 Information on how Podman configures [OCI Hooks][spec-hooks] to run when launching a container. 95 96 **[Podman API](https://docs.podman.io/en/latest/_static/api.html)** 97 Documentation on the Podman REST API. 98 99 **[Podman Commands](https://podman.readthedocs.io/en/latest/Commands.html)** 100 A list of the Podman commands with links to their man pages and in many cases videos 101 showing the commands in use. 102 103 **[Podman Troubleshooting Guide](troubleshooting.md)** 104 A list of common issues and solutions for Podman. 105 106 **[Podman Usage Transfer](transfer.md)** 107 Useful information for ops and dev transfer as it relates to infrastructure that utilizes Podman. This page 108 includes tables showing Docker commands and their Podman equivalent commands. 109 110 **[Tutorials](docs/tutorials)** 111 Tutorials on using Podman. 112 113 **[Remote Client](https://github.com/containers/podman/blob/main/docs/tutorials/remote_client.md)** 114 A brief how-to on using the Podman remote client. 115 116 **[Basic Setup and Use of Podman in a Rootless environment](https://github.com/containers/podman/blob/main/docs/tutorials/rootless_tutorial.md)** 117 A tutorial showing the setup and configuration necessary to run Rootless Podman. 118 119 **[Release Notes](RELEASE_NOTES.md)** 120 Release notes for recent Podman versions. 121 122 **[Contributing](CONTRIBUTING.md)** 123 Information about contributing to this project. 124 125 [spec-hooks]: https://github.com/opencontainers/runtime-spec/blob/v1.0.2/config.md#posix-platform-hooks 126 127 ## Buildah and Podman relationship 128 129 Buildah and Podman are two complementary open-source projects that are 130 available on most Linux platforms and both projects reside at 131 [GitHub.com](https://github.com) with Buildah 132 [here](https://github.com/containers/buildah) and Podman 133 [here](https://github.com/containers/podman). Both, Buildah and Podman are 134 command line tools that work on Open Container Initiative (OCI) images and 135 containers. The two projects differentiate in their specialization. 136 137 Buildah specializes in building OCI images. Buildah's commands replicate all 138 of the commands that are found in a Dockerfile. This allows building images 139 with and without Dockerfiles while not requiring any root privileges. 140 Buildah’s ultimate goal is to provide a lower-level coreutils interface to 141 build images. The flexibility of building images without Dockerfiles allows 142 for the integration of other scripting languages into the build process. 143 Buildah follows a simple fork-exec model and does not run as a daemon 144 but it is based on a comprehensive API in golang, which can be vendored 145 into other tools. 146 147 Podman specializes in all of the commands and functions that help you to maintain and modify 148 OCI images, such as pulling and tagging. It also allows you to create, run, and maintain those containers 149 created from those images. For building container images via Dockerfiles, Podman uses Buildah's 150 golang API and can be installed independently from Buildah. 151 152 A major difference between Podman and Buildah is their concept of a container. Podman 153 allows users to create "traditional containers" where the intent of these containers is 154 to be long lived. While Buildah containers are really just created to allow content 155 to be added back to the container image. An easy way to think of it is the 156 `buildah run` command emulates the RUN command in a Dockerfile while the `podman run` 157 command emulates the `docker run` command in functionality. Because of this and their underlying 158 storage differences, you can not see Podman containers from within Buildah or vice versa. 159 160 In short, Buildah is an efficient way to create OCI images while Podman allows 161 you to manage and maintain those images and containers in a production environment using 162 familiar container cli commands. For more details, see the 163 [Container Tools Guide](https://github.com/containers/buildah/tree/master/docs/containertools). 164 165 ## [Podman Hello](https://podman.io/images/podman-hello.jpg) 166 ``` 167 $ podman run quay.io/podman/hello 168 Trying to pull quay.io/podman/hello:latest... 169 Getting image source signatures 170 Copying blob a6b3126f3807 done 171 Copying config 25c667d086 done 172 Writing manifest to image destination 173 Storing signatures 174 !... Hello Podman World ...! 175 176 .--"--. 177 / - - \ 178 / (O) (O) \ 179 ~~~| -=(,Y,)=- | 180 .---. /` \ |~~ 181 ~/ o o \~~~~.----. ~~ 182 | =(X)= |~ / (O (O) \ 183 ~~~~~~~ ~| =(Y_)=- | 184 ~~~~ ~~~| U |~~ 185 186 Project: https://github.com/containers/podman 187 Website: https://podman.io 188 Documents: https://docs.podman.io 189 Twitter: @Podman_io 190 ``` 191 192 ## Podman Former API (Varlink) 193 Podman formerly offered a Varlink-based API for remote management of containers. However, this API 194 was replaced by the REST API. Varlink support has been removed as of the 3.0 release. 195 For more details, you can see [this blog](https://podman.io/blogs/2020/01/17/podman-new-api.html).