simple snapshotting script

create-cinder-snapshot.rb

#!/opt/chef/embedded/bin/ruby

#
# Create/manage Cinder volume snapshots
#

require 'mixlib/shellout'
require 'fog/openstack'

#
# Assemble our SnapshotRobot
#
class SnapshotRobot
  attr_accessor :client, :options, :server, :volume

  def initialize(opts)
    @client = Fog::Compute.new(
      provider: :openstack, openstack_tenant: ENV['OS_TENANT_NAME'],
      openstack_username: ENV['OS_USERNAME'], openstack_api_key: ENV['OS_PASSWORD'],
      openstack_auth_url: "#{ENV['OS_AUTH_URL']}/tokens"
    )
    @options = opts
    server_id = File.read('/var/lib/cloud/data/instance-id').chomp
    @server = @client.servers.get(server_id)
    @volume = @client.volumes.detect do |vol|
      vol.attachments.first['serverId'] == server.id
    end
  end

  def run!
    stop!
    snap!
    start!
  end

  private

  def stop!
    manage_units!(:stop, @options[:services])
    manage_units!(:kill, @options[:services]) if @options[:kill]
    manage_units!(:stop, @options[:mounts])
  end

  def snap!
    detach_volume!(@server, @volume)
    create_snapshot!(@volume)
    attach_volume!(@server, @volume)
    Mixlib::ShellOut.new('systemctl daemon-reload').run_command
  end

  def start!
    manage_units!(:start, @options[:mounts])
    manage_units!(:start, @options[:services])
  end

  def manage_units!(action, unit_list)
    unit_list.each do |unit|
      Mixlib::ShellOut
        .new("systemctl #{action} #{unit}", timeout: 3_600)
        .tap(&:run_command)
        .error!
    end
  end

  def detach_volume!(server, volume)
    server.detach_volume(volume.id)
    volume.wait_for { status == 'available' }
  end

  def create_snapshot!(volume)
    name = "#{@volume.name}-#{Time.now.to_i}"
    @client.create_snapshot(volume.id, name, 'Roderick was here.')
    @client.snapshots
      .find { |snap| snap.name == name }
      .wait_for { status == 'available' }
  end

  def attach_volume!(server, volume)
    server.attach_volume(volume.id, '/dev/vdb')
    volume.wait_for { status == 'in-use' }
  end
end

#
# Turn the SnapshotRobot loose.
# Isn't little Roderick so cute?
#

require 'optparse'

options = {}

optparser = OptionParser.new do |opts|
  opts.banner = 'Usage: create-cinder-snapshot.rb [options]'

  opts.on('--services x,y,z', Array, 'Services to stop/start.') do |s|
    options[:services] = s
  end

  opts.on('--mounts x,y,z', Array, 'Mount units to umount/mount.') do |m|
    options[:mounts] = m
  end

  opts.on('--kill', 'Kill services after stopping.') do |k|
    options[:kill] = k
  end
end

optparser.parse!

begin
  puts "Starting snapshotting."
  roderick = SnapshotRobot.new(options)
  roderick.run!
rescue StandardError => error
  puts "Failed snapshotting!"
  puts "ERROR: #{error.message}"
else
  puts "Finished snapshotting."
ensure
  puts 'Going into sleep mode.'
end

example usage:

[root@ws-gluster0 ~(WDC_STAGING)]# ./snapshot-robot.rb -s glusterd.service -m srv-workspaces.mount,srv-data.mount -k
Starting snapshotting
Finished snapshotting
Going into sleep mode.