openstack/ironic-python-agent
Code Issues Proposed changes

Don't try to put a bootloader in place when bootable

Browse Source 
Lets not do silly things and if the disk looks bootable,
and we're not trying to do UEFI, then let us assume the
proper thing will occur upon power-up.

Looks at the boot sector data and if an executable is
found in the first 218 bytes, then it bypasses loading
a boot loader.

Also adds a dependency on the "file" linux distribution
package.

Change-Id: I11bc26670a08ee13174a43d7cd0f1ab9c1bd35cf
Story: 2006474
Task: 36410
This commit is contained in:
Julia Kreger 2019-08-29 16:22:50 -04:00
parent c5956bdada
commit 9f8fa2853a
4 changed files with 138 additions and 9 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
bindep.txt
View File

@ -26,3 +26,4 @@ python-pip [imagebuild]
unzip [imagebuild]
sudo [imagebuild]
gawk [imagebuild]
file [imagebuild]

64
ironic_python_agent/extensions/image.py
View File

@ -134,6 +134,51 @@ def _has_dracut(root):
return True
def _is_bootloader_loaded(dev):
"""Checks the device to see if a MBR bootloader is present.
:param str dev: Block device upon which to check if it appears
to be bootable via MBR.
:returns: True if a device appears to be bootable with a boot
loader, otherwise False.
"""
def _has_boot_sector(device):
"""Check the device for a boot sector indiator."""
stdout, stderr = utils.execute('file', '-s', device)
if 'boot sector' in stdout:
# Now lets check the signature
ddout, dderr = utils.execute(
'dd', 'if=%s' % device, 'bs=218', 'count=1')
stdout, stderr = utils.execute('file', '-', process_input=ddout)
# The bytes recovered by dd show as a "dos executable" when
# examined with file. In other words, the bootloader is present.
if 'executable' in stdout:
return True
return False
try:
# Looking for things marked "bootable" in the partition table
stdout, stderr = utils.execute('parted', dev, '-s', '-m',
'--', 'print')
except processutils.ProcessExecutionError:
return False
lines = stdout.splitlines()
for line in lines:
partition = line.split(':')
try:
# Find the bootable device, and check the base
# device and partition for bootloader contents.
if 'boot' in partition[6]:
if (_has_boot_sector(dev)
or _has_boot_sector(partition[0])):
return True
except IndexError:
continue
return False
def _install_grub2(device, root_uuid, efi_system_part_uuid=None,
prep_boot_part_uuid=None):
"""Install GRUB2 bootloader on a given device."""
@ -143,6 +188,19 @@ def _install_grub2(device, root_uuid, efi_system_part_uuid=None,
efi_partition_mount_point = None
efi_mounted = False
# If the root device is an md device (or partition), restart the device
# (to help grub finding it) and identify the underlying holder disks
# to install grub.
if hardware.is_md_device(device):
hardware.md_restart(device)
elif (_is_bootloader_loaded(device)
and not (efi_system_part_uuid
or prep_boot_part_uuid)):
# We always need to put the bootloader in place with software raid
# so it is okay to elif into the skip doing a bootloader step.
LOG.info("Skipping installation of bootloader on device %s "
"as it is already marked bootable.", device)
return
try:
# Mount the partition and binds
path = tempfile.mkdtemp()
@ -155,11 +213,9 @@ def _install_grub2(device, root_uuid, efi_system_part_uuid=None,
if prep_boot_part_uuid:
device = _get_partition(device, uuid=prep_boot_part_uuid)
# If the root device is an md device (or partition), restart the device
# (to help grub finding it) and identify the underlying holder disks
# to install grub.
# If the root device is an md device (or partition),
# identify the underlying holder disks to install grub.
if hardware.is_md_device(device):
hardware.md_restart(device)
disks = hardware.get_holder_disks(device)
else:
disks = [device]

74
ironic_python_agent/tests/unit/extensions/test_image.py
View File

@ -91,6 +91,7 @@ class TestImageExtension(base.IronicAgentTest):
prep_boot_part_uuid=self.fake_prep_boot_part_uuid)
mock_iscsi_clean.assert_called_once_with(self.fake_dev)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: False)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
@mock.patch.object(hardware, 'md_get_raid_devices', autospec=True)
@mock.patch.object(os, 'environ', autospec=True)
@ -100,7 +101,7 @@ class TestImageExtension(base.IronicAgentTest):
mock_execute, mock_dispatch):
mock_get_part_uuid.return_value = self.fake_root_part
environ_mock.get.return_value = '/sbin'
mock_is_md_device.side_effect = [False, False]
mock_is_md_device.return_value = False
mock_md_get_raid_devices.return_value = {}
image._install_grub2(self.fake_dev, self.fake_root_uuid)
@ -137,6 +138,7 @@ class TestImageExtension(base.IronicAgentTest):
uuid=self.fake_root_uuid)
self.assertFalse(mock_dispatch.called)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: False)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
@mock.patch.object(hardware, 'md_get_raid_devices', autospec=True)
@mock.patch.object(os, 'environ', autospec=True)
@ -147,9 +149,8 @@ class TestImageExtension(base.IronicAgentTest):
mock_get_part_uuid.side_effect = [self.fake_root_part,
self.fake_prep_boot_part]
environ_mock.get.return_value = '/sbin'
mock_is_md_device.side_effect = [False, False]
mock_is_md_device.return_value = False
mock_md_get_raid_devices.return_value = {}
image._install_grub2(self.fake_dev, self.fake_root_uuid,
prep_boot_part_uuid=self.fake_prep_boot_part_uuid)
@ -189,6 +190,7 @@ class TestImageExtension(base.IronicAgentTest):
uuid=self.fake_prep_boot_part_uuid)
self.assertFalse(mock_dispatch.called)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: True)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
@mock.patch.object(hardware, 'md_get_raid_devices', autospec=True)
@mock.patch.object(os, 'environ', autospec=True)
@ -252,6 +254,7 @@ class TestImageExtension(base.IronicAgentTest):
uuid=self.fake_efi_system_part_uuid)
self.assertFalse(mock_dispatch.called)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: False)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
@mock.patch.object(hardware, 'md_get_raid_devices', autospec=True)
@mock.patch.object(os, 'environ', autospec=True)
@ -305,6 +308,7 @@ class TestImageExtension(base.IronicAgentTest):
attempts=3, delay_on_retry=True)]
mock_execute.assert_has_calls(expected)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: False)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
@mock.patch.object(hardware, 'md_get_raid_devices', autospec=True)
@mock.patch.object(os, 'environ', autospec=True)
@ -342,6 +346,7 @@ class TestImageExtension(base.IronicAgentTest):
delay_on_retry=True)]
mock_execute.assert_has_calls(expected)
@mock.patch.object(image, '_is_bootloader_loaded', lambda *_: False)
@mock.patch.object(image, '_get_partition', autospec=True)
def test__install_grub2_command_fail(self, mock_get_part_uuid,
mock_execute,
@ -356,9 +361,11 @@ class TestImageExtension(base.IronicAgentTest):
uuid=self.fake_root_uuid)
self.assertFalse(mock_dispatch.called)
@mock.patch.object(image, '_is_bootloader_loaded', autospec=True)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
def test__get_partition(self, mock_is_md_device, mock_execute,
mock_dispatch):
def test__get_partition(self, mock_is_md_device, mock_is_bootloader,
mock_execute, mock_dispatch):
mock_is_md_device.side_effect = [False]
mock_is_md_device.side_effect = [False, False]
lsblk_output = ('''KNAME="test" UUID="" TYPE="disk"
KNAME="test1" UUID="256a39e3-ca3c-4fb8-9cc2-b32eec441f47" TYPE="part"
@ -374,6 +381,7 @@ class TestImageExtension(base.IronicAgentTest):
self.fake_dev)]
mock_execute.assert_has_calls(expected)
self.assertFalse(mock_dispatch.called)
self.assertFalse(mock_is_bootloader.called)
@mock.patch.object(hardware, 'is_md_device', autospec=True)
def test__get_partition_no_device_found(self, mock_is_md_device,
@ -459,3 +467,59 @@ class TestImageExtension(base.IronicAgentTest):
self.fake_dev)]
mock_execute.assert_has_calls(expected)
self.assertFalse(mock_dispatch.called)
def test__is_bootloader_loaded(self, mock_execute,
mock_dispatch):
parted_output = ('BYT;\n'
'/dev/loop1:46.1MB:loopback:512:512:gpt:Loopback '
'device:;\n'
'15:1049kB:9437kB:8389kB:::boot;\n'
'1:9437kB:46.1MB:36.7MB:ext3::;\n')
disk_file_output = ('/dev/loop1: partition 1: ID=0xee, starthead 0, '
'startsector 1, 90111 sectors, extended '
'partition table (last)\011, code offset 0x48')
part_file_output = ('/dev/loop1p15: x86 boot sector, mkdosfs boot '
'message display, code offset 0x3c, OEM-ID '
'"mkfs.fat", sectors/cluster 8, root entries '
'512, sectors 16384 (volumes <=32 MB) , Media '
'descriptor 0xf8, sectors/FAT 8, heads 255, '
'serial number 0x23a08feb, unlabeled, '
'FAT (12 bit)')
# NOTE(TheJulia): File evaluates this data, so it is pointless to
# try and embed the raw bytes in the test.
dd_output = ('')
file_output = ('/dev/loop1: DOS executable (COM)\n')
mock_execute.side_effect = iter([(parted_output, ''),
(disk_file_output, ''),
(part_file_output, ''),
(dd_output, ''),
(file_output, '')])
result = image._is_bootloader_loaded(self.fake_dev)
self.assertTrue(result)
def test__is_bootloader_loaded_not_bootable(self,
mock_execute,
mock_dispatch):
parted_output = ('BYT;\n'
'/dev/loop1:46.1MB:loopback:512:512:gpt:Loopback '
'device:;\n'
'15:1049kB:9437kB:8389kB:::;\n'
'1:9437kB:46.1MB:36.7MB:ext3::;\n')
mock_execute.return_value = (parted_output, '')
result = image._is_bootloader_loaded(self.fake_dev)
self.assertFalse(result)
def test__is_bootloader_loaded_empty(self,
mock_execute,
mock_dispatch):
parted_output = ('BYT;\n'
'/dev/loop1:46.1MB:loopback:512:512:gpt:Loopback '
'device:;\n')
mock_execute.return_value = (parted_output, '')
result = image._is_bootloader_loaded(self.fake_dev)
self.assertFalse(result)

8
releasenotes/notes/skips-bootloader-install-35c463195aa61800.yaml Normal file
View File

@ -0,0 +1,8 @@
---
fixes:
- |
Fixes an issue where wholedisk images are requested for deployment and
the bootloader is overridden. IPA now explicitly looks for the boot
partition, and examines the contents if the disk appears to be MBR
bootable. If override/skip bootloader installation does not apply if
UEFI or PREP boot partitions are present on the disk.