Source Code for Module virtualization.start_domain

  1  # 
  2  # Copyright (c) 2008--2013 Red Hat, Inc. 
  3  # 
  4  # This software is licensed to you under the GNU General Public License, 
  5  # version 2 (GPLv2). There is NO WARRANTY for this software, express or 
  6  # implied, including the implied warranties of MERCHANTABILITY or FITNESS 
  7  # FOR A PARTICULAR PURPOSE. You should have received a copy of GPLv2 
  8  # along with this software; if not, see 
  9  # http://www.gnu.org/licenses/old-licenses/gpl-2.0.txt. 
 10  # 
 11  # Red Hat trademarks are not licensed under GPLv2. No permission is 
 12  # granted to use or replicate Red Hat trademarks that are incorporated 
 13  # in this software or its documentation. 
 14  # 
 15   
 16  try: 
 17      # python 2 
 18      import commands 
 19  except ImportError: 
 20      import subprocess as commands 
 21   
 22  import libvirt 
 23  import os 
 24  import os.path 
 25  import re 
 26  import sys 
 27   
 28  from virtualization.domain_directory import DomainDirectory 
 29  from virtualization.domain_config    import DomainConfig, DomainConfigError 
 30  from virtualization.errors           import VirtualizationException 
 31  from spacewalk.common.usix import raise_with_tb 
 32   
 33  ############################################################################### 
 34  # Constants 
 35  ############################################################################### 
 36   
 37  PYGRUB = "/usr/bin/pygrub" 
 38   
 39  ############################################################################### 
 40  # Public Interface 
 41  ############################################################################### 
 42   
 43 -def start_domain(uuid): 
 44      """ 
 45      Boots the domain for the first time after installation is complete. 
 46      """ 
 47      # Load the configuration file for this UUID. 
 48      domain = DomainDirectory() 
 49      config = domain.load_config(uuid) 
 50   
 51      # Connect to the hypervisor. 
 52      connection = libvirt.open(None) 
 53   
 54      # We will attempt to determine if the domain is configured to use a 
 55      # bootloader.  If not, we'll have to explicitly use the kernel and initrd 
 56      # data provided in the config to start the domain. 
 57      try: 
 58          config.getConfigItem(DomainConfig.BOOTLOADER) 
 59      except DomainConfigError: 
 60          dce = sys.exc_info()[1] 
 61          # No bootloader tag present.  Use pygrub to extract the kernel from 
 62          # the disk image if its Xen. For fully virt we dont have pygrub, it 
 63          # directly emulates the BIOS loading the first sector of the boot disk. 
 64          if connection.getType() == 'Xen': 
 65              # This uses pygrub which comes only with xen 
 66              _prepare_guest_kernel_and_ramdisk(config) 
 67   
 68      # Now, we'll restart the instance, this time using the re-create XML. 
 69      try: 
 70          domain = connection.createLinux(config.toXML(), 0) 
 71      except Exception: 
 72          e = sys.exc_info()[1] 
 73          raise_with_tb(VirtualizationException("Error occurred while attempting to recreate domain %s: %s" % 
 74                                                (uuid, str(e))), sys.exc_info()[2]) 
 75   
 76  ############################################################################### 
 77  # Helper Methods 
 78  ############################################################################### 
 79   
 80 -def _prepare_guest_kernel_and_ramdisk(config): 
 81      """ 
 82      Use PyGrub to extract the kernel and ramdisk from the given disk image. 
 83      """ 
 84   
 85      disk_image = config.getConfigItem(DomainConfig.DISK_IMAGE_PATH) 
 86   
 87      # Use pygrub to extract the initrd and the kernel from the disk image. 
 88      (status, output) = \ 
 89          commands.getstatusoutput("%s -q %s" % (PYGRUB, disk_image)) 
 90      if status != 0: 
 91          raise VirtualizationException("Error occurred while executing '%s' (status=%d). Output=%s" % 
 92                                        (PYGRUB, status, output)) 
 93   
 94      # Now analyze the output and extract the names of the new kernel and initrd 
 95      # images from it. 
 96      (pygrub_kernel_path, pygrub_initrd_path) = \ 
 97          _extract_image_paths_from_pygrub_output(output) 
 98   
 99      # Rename the extracted images to the names we are pointing to in the 
100      # configuration file. 
101      runtime_kernel_path = config.getConfigItem(DomainConfig.KERNEL_PATH) 
102      runtime_initrd_path = config.getConfigItem(DomainConfig.RAMDISK_PATH) 
103   
104      try: 
105          os.rename(pygrub_kernel_path, runtime_kernel_path) 
106          os.rename(pygrub_initrd_path, runtime_initrd_path) 
107      except OSError: 
108          oe = sys.exc_info()[1] 
109          raise_with_tb(VirtualizationException("Error occurred while renaming runtime image paths: %s" % str(oe)), 
110                        sys.exc_info()[2]) 
111   
112   
113 -def _extract_image_paths_from_pygrub_output(output): 
114      """ 
115      Searches for the paths of the kernel and initrd files in the output of 
116      pygrub.  If not found, a VirtualizationException is raised.  Otherwise, 
117      the (kernel_path, initrd_path) tuple is returned. 
118      """ 
119      match = re.search("^linux \(kernel (\S+)\)\(ramdisk (\S+)\)", 
120                        output, 
121                        re.MULTILINE) 
122      if match is None or len(match.groups()) != 2: 
123          raise VirtualizationException("Could not locate kernel and initrd in pygrub output: %s" % output) 
124   
125      kernel_path = match.group(1) 
126      initrd_path = match.group(2) 
127   
128      return (kernel_path, initrd_path) 
129   
130  if __name__ == "__main__": 
131      print("result=", start_domain(sys.argv[1])) 
132