ruby unshare (runshare)

This tool allows to unshare Linux namespaces. The implementation is similar to the unshare(1) tool.

Installation

Add this line to your application's Gemfile:

    gem 'runshare'

And then execute:

$ bundle

Or install it yourself as:

$ gem install runshare

Usage

> require "runshare"
> RUnshare::unshare

For example:

cat > test.rb

require "runshare"

pid = RUnshare::unshare(
  :clone_newpid    => true,
  :clone_newns     => true,
  :clone_newcgroup => true,
  :clone_newipc    => true,
  :clone_newuts    => true,
  :clone_newnet    => true,
  :clone_newtime   => true,
  :fork            => true,
  :mount_proc      => "/proc",
  # docker export $(docker create hello-world) | tar -xf - -C rootfs
  :root            => "/tmp/rootfs"
)

if pid == 0
  # child
  puts "--- #{Process.pid}"
  if system("/hello") != true
    raise "bad"
  end
  puts "--- done"
else
  # parent
  puts "-- unshare=#{pid}, pid=#{Process.pid}"
  puts "-- exit=#{Process.waitpid(pid)}"
end

^D

sudo ruby -I ./lib ./test.rb

Quick start

$ rake compile && echo 'require "runshare"; RUnshare::unshare(:clone_newuts => true)' | irb
install -c tmp/x86_64-linux/runshare/2.4.10/runshare.so lib/runshare/runshare.so
cp tmp/x86_64-linux/runshare/2.4.10/runshare.so tmp/x86_64-linux/stage/lib/runshare/runshare.so
Switch to inspect mode.
require "runshare"; RUnshare::unshare

Ruby <2.5

If your app is single threaded and you are observing:

eval:1: warning: pthread_create failed for timer: Invalid argument, scheduling broken

Just ignore it with some degree of bravity. You also can silence it by setting:

$VERBOSE = nil

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake spec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/sitano/runshare. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.