lifubang
c77e71a3e7
This commit factors out setupAndMountToRootfs without changing any logic. Use "Hide whitespace changes" during review to focus on the actual changes. The refactor ensures the mount source file descriptor is closed via defer in each loop iteration, reducing the total number of open FDs in runc. This helps avoid hitting the file descriptor limit under high concurrency or when handling many mounts. Signed-off-by: lifubang <lifubang@acmcoder.com>
libcontainer
Libcontainer provides a native Go implementation for creating containers with namespaces, cgroups, capabilities, and filesystem access controls. It allows you to manage the lifecycle of the container performing additional operations after the container is created.
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.
Using libcontainer
For a brief overview of using libcontainer, see example_test.go.
Container init
Because containers are spawned in a two step process you will need a binary that will be executed as the init process for the container. In libcontainer, we use the current binary (/proc/self/exe) to be executed as the init process, and use arg "init", we call the first step process "bootstrap", so you always need a "init" function as the entry of "bootstrap".
In addition to the go init function the early stage bootstrap is handled by importing nsenter.
For details on how runc implements such "init", see ../init.go and init_linux.go.
Checkpoint & Restore
libcontainer now integrates CRIU for checkpointing and restoring containers. This lets you save the state of a process running inside a container to disk, and then restore that state into a new process, on the same machine or on another machine.
criu version 1.5.2 or higher is required to use checkpoint and restore.
If you don't already have criu installed, you can build it from source, following the
online instructions. criu is also installed in the docker image
generated when building libcontainer with docker.
Copyright and license
Code and documentation copyright 2014 Docker, inc. The code and documentation are released under the Apache 2.0 license. The documentation is also released under 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/.