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diff --git a/vendor/src/github.com/docker/libcontainer/README.md b/vendor/src/github.com/docker/libcontainer/README.md index 068c66e6cf..ee14a57ce1 100644 --- a/vendor/src/github.com/docker/libcontainer/README.md +++ b/vendor/src/github.com/docker/libcontainer/README.md @@ -1,40 +1,49 @@ ## libcontainer - reference implementation for containers +### Note on API changes: + +Please bear with us while we work on making the libcontainer API stable and something that we can support long term. We are currently discussing the API with the community, therefore, if you currently depend on libcontainer please pin your dependency at a specific tag or commit id. Please join the discussion and help shape the API. + #### Background -libcontainer specifies configuration options for what a container is. It provides a native Go implementation -for using Linux namespaces with no external dependencies. libcontainer provides many convenience functions for working with namespaces, networking, and management. +libcontainer specifies configuration options for what a container is. It provides a native Go implementation for using Linux namespaces with no external dependencies. libcontainer provides many convenience functions for working with namespaces, networking, and management. #### Container -A container is a self contained directory that is able to run one or more processes without -affecting the host system. The directory is usually a full system tree. Inside the directory -a `container.json` file is placed with the runtime configuration for how the processes -should be contained and run. Environment, networking, and different capabilities for the -process are specified in this file. The configuration is used for each process executed inside the container. +A container is a self contained execution environment that shares the kernel of the host system and which is (optionally) isolated from other containers in the system. + +libcontainer may be used to execute a process in a container. If a user tries to run a new process inside an existing container, the new process is added to the processes executing in the container. + + +#### Root file system -See the `container.json` file for what the configuration should look like. +A container runs with a directory known as its *root file system*, or *rootfs*, mounted as the file system root. The rootfs is usually a full system tree. -Using this configuration and the current directory holding the rootfs for a process, one can use libcontainer to exec the container. Running the life of the namespace, a `pid` file -is written to the current directory with the pid of the namespaced process to the external world. A client can use this pid to wait, kill, or perform other operation with the container. If a user tries to run a new process inside an existing container with a live namespace, the namespace will be joined by the new process. -You may also specify an alternate root place where the `container.json` file is read and where the `pid` file will be saved. +#### Configuration + +A container is initially configured by supplying configuration data when the container is created. + #### nsinit -`nsinit` is a cli application used as the reference implementation of libcontainer. It is able to -spawn or join new containers giving the current directory. To use `nsinit` cd into a Linux -rootfs and copy a `container.json` file into the directory with your specified configuration. +`nsinit` is a cli application which demonstrates the use of libcontainer. It is able to spawn new containers or join existing containers, based on the current directory. -To execute `/bin/bash` in the current directory as a container just run: +To use `nsinit`, cd into a Linux rootfs and copy a `container.json` file into the directory with your specified configuration. Environment, networking, and different capabilities for the container are specified in this file. The configuration is used for each process executed inside the container. + +See the `sample_configs` folder for examples of what the container configuration should look like. + +To execute `/bin/bash` in the current directory as a container just run the following **as root**: ```bash nsinit exec /bin/bash ``` -If you wish to spawn another process inside the container while your current bash session is -running just run the exact same command again to get another bash shell or change the command. If the original process dies, PID 1, all other processes spawned inside the container will also be killed and the namespace will be removed. +If you wish to spawn another process inside the container while your current bash session is running, run the same command again to get another bash shell (or change the command). If the original process (PID 1) dies, all other processes spawned inside the container will be killed and the namespace will be removed. + +You can identify if a process is running in a container by looking to see if `state.json` is in the root of the directory. + +You may also specify an alternate root place where the `container.json` file is read and where the `state.json` file will be saved. -You can identify if a process is running in a container by looking to see if `pid` is in the root of the directory. #### Future See the [roadmap](ROADMAP.md). |