LXC Ruby Wrapper

Ruby library to integrate with Linux Containers CLI tools

Requirements

Supported LXC versions:

0.7.5
0.8.0

For testing purposes you can use Vagrant with VirtualBox. Most of the functionality was tested on 64-bit Ubuntu 11.10 and 12.04. Recommended version is 12.04. Additional boxes could be found here.

Installation

Add it to your Gemfile:

gem 'lxc-ruby'

Or install it manually:

gem install lxc-ruby

Usage

You should have LXC already installed on your system before using the library.

Example:

require 'lxc'

# Check if all lxc binaries are installed
LXC.installed?

# Get LXC version
LXC.version

# Get current LXC configuration
LXC.config

# Get a list of all containers
LXC.containers

# Get a single container by name
LXC.container('name')

Container instance is a simple abstaction for lxc's container tools:

c = LXC.container('foo')

# Get current status of container
c.state  # => 'running'
c.pid    # => 1234
c.status # => <LXC::Status @state='running' @pid=123456>

# Check if container exists?
#
# This is needed since lxc does not raise any errors if container is
# not present in the system, and returns the same result as if container
# is actually stopped
c.exists? # => true

# Status helpers
c.running? # => true
c.stopped? # => false
c.frozen?  # => false

# Start and stop containers
c.start # will be started in daemonized mode
c.stop

# Free and unfreeze (also returns current status)
c.freeze
c.unfreeze

# Destroy container
c.destroy # => true

Container metrics:

# Get container memory usage (in bytes)
c.memory_usage
c.memory_limit

# Get container cpu shares and usage (in seconds)
c.cpu_shares # => 1024
c.cpu_usage  # => 4312.08

# Get running processes
c.processes 
# => 
#[{"pid"=>"27404",
#   "user"=>"root",
#   "cpu"=>"0.0",
#   "memory"=>"0.1",
#   "command"=>"/sbin/init",
#   "args"=>""}]

To create a new container:

c = LXC::Container.new('foo')
c.create(path_to_lxc_config)

This method invokes lxc-create -n NAME -f CONFIG command. It DOES NOT create any rootfs images or configures anything.

Running with sudo

By default LXC does not allow to run its command under unprivileged user. There are two ways to make it work:

Using sudo

LXC.use_sudo = true

Using lxc-setcap

If you want to make container usable by non-root users, run lxc-setcap as root, and some capabilities will be set so that normal users will be able to use the container utils. This is not done by default, though, and you have to explicitly allow it.

Testing

To run the test suite execute:

rake test

License

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.