Class: Mist::LXCContainer

Inherits:
Object
  • Object
show all
Defined in:
lib/mist/lxc_container.rb

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(name, distro = nil, release = nil) ⇒ LXCContainer

Returns a new instance of LXCContainer.



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# File 'lib/mist/lxc_container.rb', line 21

def initialize(name, distro = nil, release = nil)
  @name = name
  @distro = distro
  @release = release

  @container = LXC::Container.new(@name)
  @ips = []
end

Instance Attribute Details

#distro ⇒ Object (readonly)

Returns the value of attribute distro.



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# File 'lib/mist/lxc_container.rb', line 19

def distro
  @distro
end

#ips ⇒ Object (readonly)

Returns the value of attribute ips.



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# File 'lib/mist/lxc_container.rb', line 19

def ips
  @ips
end

#name ⇒ Object (readonly)

Returns the value of attribute name.



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# File 'lib/mist/lxc_container.rb', line 19

def name
  @name
end

#release ⇒ Object (readonly)

Returns the value of attribute release.



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# File 'lib/mist/lxc_container.rb', line 19

def release
  @release
end

Instance Method Details

#create(config, startup_script) ⇒ Object 



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# File 'lib/mist/lxc_container.rb', line 34

def create(config, startup_script)
  raise "Container #{@name} already exists!" if exists?

  # Find the template for this container; if one does not exist on the host,
  # create it.
  template = LXCTemplate.new(distro, release)
  unless template.exists?
    Mist.logger.info "Template for #{distro}-#{release} does not exist"
    template.create(config)
  end

  # Fast-clone a new container from the template
  Mist.logger.info 'Cloning template...'
  container = template.clone(@name)

  begin
    # Start the container
    Mist.logger.info "Starting #{@name}"

    container.start
    container.wait(:running, 30)

    # Wait for the network to start
    Mist.logger.info 'Waiting for network...'

    @ips = []
    start = Time.now
    loop do
      @ips = container.ip_addresses
      break unless @ips.empty?

      sleep 1

      raise 'timed out waiting for network' \
        if (Time.now - start) >= 30
    end

    # Give the container a few more seconds to allow SSH to start
    socket = Socket.new(Socket::AF_INET, Socket::SOCK_STREAM, 0)
    sockaddr = Socket.sockaddr_in(22, @ips.first)
    start = Time.now
    loop do
      begin
        if socket.connect_nonblock(sockaddr) == 0
          Mist.logger.info 'SSH started'
          socket.close
          break
        else
          sleep 0.5
        end

        raise 'timed out waiting for SSH' \
          if (Time.now - start) >= 30
      rescue Errno::ECONNREFUSED, Errno::EWOULDBLOCK, Errno::EINPROGRESS
        # Ignored
      end
    end

    # Find the rootfs on the host so that we can copy in the startup-script
    rootfs = container.config_item('lxc.rootfs')
    match = rootfs.match(/\Aoverlayfs:(.*):(.*)\Z/)
    rootfs = match[2] if match

    Mist.logger.debug "rootfs=#{rootfs}"

    internal_path = File.join('/', 'var', 'lib', 'mist')
    internal_file = File.join(internal_path, 'startup')
    external_path = File.join(rootfs, internal_path)
    external_file = File.join(external_path, 'startup')

    begin
      ::FileUtils.mkdir_p(external_path)
      ::FileUtils.cp startup_script, external_file
    rescue StandardError => ex
      Mist.logger.error "failed to copy startup script: #{ex}"
      raise 'could not copy startup script to container'
    end

    # Run the startup script
    Mist.logger.debug 'running startup script'
    container.attach(wait: true, stdin: File.open('/dev/null')) do
      LXC.run_command("/bin/bash #{internal_file}")
    end
  rescue StandardError => ex
    Mist.logger.error "Failed to start container #{@name}: #{ex}"

    # Attempt to clean up
    container.stop if container.running?
    container.destroy if container.defined?

    raise
  end

  @container = container
end

#destroy ⇒ Object 



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# File 'lib/mist/lxc_container.rb', line 130

def destroy
  raise "Container #{@name} does not exist!" unless exists?

  begin
    @container.stop
    @container.wait(:stopped, 60)
    @container.destroy

    @container = nil
    @ips = []
  rescue StandardError => ex
    Mist.logger.error "Failed to destroy container #{@name}: #{ex}"
    raise
  end
end

#exists? ⇒ Boolean

Returns:

  • (Boolean) 


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# File 'lib/mist/lxc_container.rb', line 30

def exists?
  @container.defined?
end