Class: Vmit::VirtualMachine

Inherits:
Object
  • Object
show all
Defined in:
lib/vmit/virtual_machine.rb

Constant Summary collapse

VM_DEFAULTS = 
{
  :memory => '1G',
}
SWITCH = 
'br0'
DISK_INIT_DEFAULTS = 
{:disk_size => '10G'}
BINDIR = 
File.join(File.dirname(__FILE__), '../../bin')

Instance Attribute Summary collapse

Instance Method Summary collapse

Constructor Details

#initialize(work_dir) ⇒ VirtualMachine

Returns a new instance of VirtualMachine.



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# File 'lib/vmit/virtual_machine.rb', line 49

def initialize(work_dir)
  @pidfile = PidFile.new(:piddir => work_dir, :pidfile => "vmit.pid")
  @work_dir = work_dir

  @opts = {}
  @opts.merge!(VM_DEFAULTS)

  if File.exist?(config_file)
    @opts.merge!(YAML::load(File.open(config_file)))
  end

  # By default the following keys are useful to be
  # generated if they don't exist and then use the
  # same in the future UNLESS they are
  # overriden with vmit run
  if not @opts.has_key?(:mac_address)
    @opts[:mac_address] = Vmit::Utils.random_mac_address
  end

  if not @opts.has_key?(:uuid)
    @opts[:uuid] = File.read("/proc/sys/kernel/random/uuid").strip
  end

  @network = if @opts.has_key?(:network)
    Network.create(@opts[:network])
  else
    Vmit.logger.info 'No network selected. Using default.'
    Network.default
  end
  Vmit.logger.info "Network: #{@network}"
end

Instance Attribute Details

#work_dir ⇒ Object

Returns the value of attribute work_dir.



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# File 'lib/vmit/virtual_machine.rb', line 33

def work_dir
  @work_dir
end

Instance Method Details

#[](key) ⇒ Object

Accessor to current options



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# File 'lib/vmit/virtual_machine.rb', line 41

def [](key)
  @opts[key]
end

#config ⇒ Hash

Returns Config of the virtual machine This is all options plus the defaults.

Returns:

  • (Hash) —

    Config of the virtual machine This is all options plus the defaults



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# File 'lib/vmit/virtual_machine.rb', line 155

def config
  VM_DEFAULTS.merge(@opts)
end

#config_file ⇒ Object 



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# File 'lib/vmit/virtual_machine.rb', line 45

def config_file
  File.join(work_dir, 'config.yml')
end

#current_image ⇒ Object 



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# File 'lib/vmit/virtual_machine.rb', line 143

def current_image
  curr = disk_images.last
  raise "No hard disk image available" if curr.nil?
  curr
end

#disk_image_init!(opts = {}) ⇒ Object 



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# File 'lib/vmit/virtual_machine.rb', line 93

def disk_image_init!(opts={})
  disk_image_shift!(opts)
end

#disk_image_shift!(opts = {}) ⇒ Object

Shifts an image, adding a new one using the previous newest one as backing file

Parameters:

  • opts (Hash) (defaults to: {}) —

    options for the disk shift

Options Hash (opts):

  • :disk_size (String) —

    Disk size. Only used for image creation



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# File 'lib/vmit/virtual_machine.rb', line 104

def disk_image_shift!(opts={})
  runtime_opts = DISK_INIT_DEFAULTS.merge(opts)

  file_name = File.join(work_dir, "sda-#{Time.now.to_i}.qcow2")
  images = disk_images

  file_name = 'base.qcow2' if images.size == 0

  args = ['/usr/bin/qemu-img', 'create',
    '-f', "qcow2"]

  if not images.empty?
    args << '-b'
    args << images.last
  end
  args << file_name
  if images.empty?
    args << runtime_opts[:disk_size]
  end

  Vmit.logger.info "Shifted image. Current is '#{file_name}'."
  Cheetah.run(*args)
end

#disk_images ⇒ Array, <String>

Returns sorted list of snapshots.

Returns:

  • (Array, <String>) —

    sorted list of snapshots



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# File 'lib/vmit/virtual_machine.rb', line 82

def disk_images
  Dir.glob(File.join(work_dir, '*.qcow2')).sort do |a,b|
    File.ctime(a) <=> File.ctime(b)
  end
end

#disk_rollback! ⇒ Object

Rolls back to the previous snapshot



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# File 'lib/vmit/virtual_machine.rb', line 129

def disk_rollback!
  images = disk_images

  return if images.empty?

  if images.size == 1
    Vmit.logger.fatal "Only the base snapshot left!"
    return
  end
  Vmit.logger.info "Removing #{images.last}"
  FileUtils.rm(images.last)
end

#disk_snapshot! ⇒ Object

Takes a disk snapshot



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# File 'lib/vmit/virtual_machine.rb', line 89

def disk_snapshot!
  disk_image_shift!
end

#ifdown(device) ⇒ Object

Called by vmit-ifdown



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# File 'lib/vmit/virtual_machine.rb', line 292

def ifdown(device)
  Vmit.logger.info "  Bringing down interface #{device}"
  Cheetah.run '/sbin/ifconfig', device, '0.0.0.0', 'down'
  @network.disconnect_interface(device)
end

#ifup(device) ⇒ Object

Called by vmit-ifup



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# File 'lib/vmit/virtual_machine.rb', line 285

def ifup(device)
  Vmit.logger.info "  Bringing interface #{device} up"
  Cheetah.run '/sbin/ifconfig', device, '0.0.0.0', 'up'
  @network.connect_interface(device)
end

#options ⇒ Object 



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# File 'lib/vmit/virtual_machine.rb', line 149

def options
  @opts
end

#relevant_config ⇒ Hash

Returns config that differs from default and therefore relevant to be persisted in config.yml.

Returns:

  • (Hash) —

    config that differs from default and therefore relevant to be persisted in config.yml



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# File 'lib/vmit/virtual_machine.rb', line 161

def relevant_config
  config.diff(VM_DEFAULTS)
end

#run(runtime_opts) ⇒ Object

Starts the virtual machine

Parameters:

  • runtime_opts (Hash) —

    Runtime options @option runtime_opts [String] :cdrom CDROM image @option runtime_opts [String] :kernel Kernel image @option runtime_opts [String] :initrd initrd image @option runtime_opts [String] :append Kernel command line @option runtime_opts [String] :floppy Floppy (image or directory)



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# File 'lib/vmit/virtual_machine.rb', line 189

def run(runtime_opts)
  Vmit.logger.info "Starting VM..."
  # Don't overwrite @opts so that
  # run can be called various times
  opts = {}
  opts.merge!(@opts)
  opts.merge!(runtime_opts)

  config.each do |k,v|
    Vmit.logger.info "  => #{k} : #{v}"
  end

  begin
    # HACK, will be replaced by a better config system
    use_virtio = ! File.exist?(File.join(work_dir, '.disable-virtio'))

    ifup = File.expand_path(File.join(BINDIR, 'vmit-ifup'))
    ifdown = File.expand_path(File.join(BINDIR, 'vmit-ifdown'))

    args = ['/usr/bin/qemu-kvm', '-boot', 'c',
        '-m', "#{opts[:memory]}",
        '-pidfile', File.join(work_dir, 'qemu.pid')]

    if use_virtio
      args << '-drive'
      args << "file=#{current_image},if=virtio"

      args << '-netdev'
      args << "type=tap,script=#{ifup},downscript=#{ifdown},id=vnet0"
      args << '-device'
      args << "virtio-net-pci,netdev=vnet0,mac=#{opts[:mac_address]}"
    else
      args << '-drive'
      args << "file=#{current_image}"

      args << '-net'
      args << "nic,macaddr=#{opts[:mac_address]}"
      args << '-net'
      args << "tap,script=#{ifup},downscript=#{ifdown}"
    end

    # advanced options, mostly to be used by plugins
    [:cdrom, :kernel, :initrd, :append].each do |key|
      if opts.has_key?(key)
        args << "-#{key}"
        args << case opts[key]
          # append is multple
          when Array then opts[key].join(' ')
          else opts[key]
        end
      end
    end

    if opts.has_key?(:floppy)
      if File.directory?(opts[:floppy])
        args << '-fda'
        args << "fat:floppy:#{opts[:floppy]}"
      else
        Vmit.logger.warn "#{opts[:floppy]} : only directories supported"
      end
    end

    # options that translate to
    # -no-something if :something => false
    [:reboot].each do |key|
      if opts.has_key?(key)
        # default is true
        args << "-no-#{key}" if not opts[key]
      end
    end

    unless ENV['DISABLE_UUID']
      args << '-uuid'
      args << "#{opts[:uuid]}"
    end

    DRb.start_service nil, self
    ENV['VMIT_SERVER'] = DRb.uri

    ENV['VMIT_SWITCH'] = SWITCH
    Vmit.logger.debug "Vmit server listening at #{DRb.uri}"

    @network.auto do
      begin
        Cheetah.run(*args)
      ensure
        FileUtils.rm_f File.join(work_dir, 'qemu.pid')
      end
    end
  rescue PidFile::DuplicateProcessError => e
    Vmit.logger.fatal "VM in '#{work_dir}'' is already running (#{e})"
    raise
  end
end

#save_config! ⇒ Object

Saves the configuration in config.yml



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# File 'lib/vmit/virtual_machine.rb', line 166

def save_config!
  if not relevant_config.empty?
    Vmit.logger.info "Writing config.yml..."
    File.open(config_file, 'w') do |f|
      f.write(relevant_config.to_yaml)
    end
  end
end

#to_s ⇒ Object 



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# File 'lib/vmit/virtual_machine.rb', line 175

def to_s
  config.to_s
end