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CA-424403: Host reboot hangs due to root disk iscsi node.startup does #799

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CA-424403: Host reboot hangs due to root disk iscsi node.startup does #799

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92 changes: 64 additions & 28 deletions libs/sm/core/iscsi.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -26,6 +26,8 @@
from sm.core import lock
import glob
import tempfile
from contextlib import contextmanager
from pathlib import Path
from configparser import RawConfigParser
import io

Expand Down Expand Up @@ -119,15 +121,21 @@ def save_rootdisk_nodes(tmpdirname):
root_iqns = get_rootdisk_IQNs()
if root_iqns:
srcdirs = [os.path.join(_ISCSI_DB_PATH, 'nodes', iqn) for iqn in root_iqns]
util.doexec(['/bin/cp', '-a'] + srcdirs + [tmpdirname])
(rc, stdout, stderr) = util.doexec(['/bin/cp', '-a'] + srcdirs + [tmpdirname])
if rc != 0:
util.SMlog("save_rootdisk_nodes: cp FAILED rc=%d stderr=%r stdout=%r"
% (rc, stderr, stdout))


def restore_rootdisk_nodes(tmpdirname):
root_iqns = get_rootdisk_IQNs()
if root_iqns:
srcdirs = [os.path.join(tmpdirname, iqn) for iqn in root_iqns]
util.doexec(['/bin/cp', '-a'] + srcdirs +
[os.path.join(_ISCSI_DB_PATH, 'nodes')])
(rc, stdout, stderr) = util.doexec(['/bin/cp', '-a'] + srcdirs +
[os.path.join(_ISCSI_DB_PATH, 'nodes')])
if rc != 0:
util.SMlog("restore_rootdisk_nodes: cp FAILED rc=%d stderr=%r stdout=%r"
% (rc, stderr, stdout))


def rescan_target(portal, target):
Expand Down Expand Up @@ -159,12 +167,7 @@ def discovery(target, port, chapuser, chappass, targetIQN="any",
# Save configuration of root LUN nodes and restore after discovery
# otherwise when we do a discovery on the same filer as is hosting
# our root disk we'll reset the config of the root LUNs

# FIXME: Replace this with TemporaryDirectory when moving to Python3
tmpdirname = tempfile.mkdtemp()
try:
save_rootdisk_nodes(tmpdirname)

if ':' in target:
targetstring = "[%s]:%s" % (target, str(port))
else:
Expand All @@ -180,20 +183,19 @@ def discovery(target, port, chapuser, chappass, targetIQN="any",
"-n", "discovery.sendtargets.auth.password", "-v", chappass]
fail_msg = "Discovery failed. Check target settings and " \
"username/password (if applicable)"
try:

with saved_rootdisk_nodes():
if chapuser != "" and chappass != "":
exn_on_failure(cmd_discdb + ["-o", "new"], fail_msg)
exn_on_failure(cmd_discdb + ["-o", "update"] + auth_args, fail_msg)
cmd = cmd_discdb + ["--discover"]
else:
cmd = cmd_disc
(stdout, stderr) = exn_on_failure(cmd, fail_msg)
except:
raise xs_errors.XenError('ISCSILogin')
finally:
restore_rootdisk_nodes(tmpdirname)
finally:
shutil.rmtree(tmpdirname)
except xs_errors.XenError:
raise
except:
raise xs_errors.XenError('ISCSILogin')

return parse_node_output(stdout, targetIQN)

Expand Down Expand Up @@ -412,20 +414,37 @@ def stop_daemon():
exn_on_failure(cmd, failuremessage)


def restart_daemon():
stop_daemon()
if os.path.exists(os.path.join(_ISCSI_DB_PATH, 'nodes')):
try:
shutil.rmtree(os.path.join(_ISCSI_DB_PATH, 'nodes'))
except:
pass
def _clear_dir(dirpath):
"""Remove all *contents* of dirpath, keeping the directory itself.
Creates the directory if it does not yet exist. Errors on individual
entries are logged and swallowed so that a single bad entry does not
abort the entire wipe."""
p = Path(dirpath)
p.mkdir(parents=True, exist_ok=True)
for child in p.iterdir():
try:
shutil.rmtree(os.path.join(_ISCSI_DB_PATH, 'send_targets'))
except:
pass
cmd = ["/usr/bin/systemctl", "start", "iscsid.service"]
failuremessage = "Failed to start iscsi daemon"
exn_on_failure(cmd, failuremessage)
if child.is_dir(follow_symlinks=False):
shutil.rmtree(child)
else:
child.unlink()
except Exception as e:
util.SMlog("_clear_dir: failed to remove %s: %s" % (child, e))


def restart_daemon():
"""Stop iscsid, wipe the node/send_targets DB, then restart.

Boot-IQN node entries are saved before the wipe and restored
afterwards via the saved_rootdisk_nodes context manager so that
the boot nodes survive the restart.
"""
with saved_rootdisk_nodes():
stop_daemon()
for subdir in ('nodes', 'send_targets'):
_clear_dir(os.path.join(_ISCSI_DB_PATH, subdir))
cmd = ["/usr/bin/systemctl", "start", "iscsid.service"]
failuremessage = "Failed to start iscsi daemon"
exn_on_failure(cmd, failuremessage)


def wait_for_devs(targetIQN, portal):
Expand Down Expand Up @@ -565,6 +584,23 @@ def _checkAnyTGT():
return False


@contextmanager
def saved_rootdisk_nodes():
"""Context manager that snapshots the boot-IQN node DB entries into a
temporary directory on entry and restores them on exit.

The restore runs unconditionally in the finally block so it is safe to
use around operations that may raise. The temporary directory is
cleaned up automatically when the context exits.
"""
with tempfile.TemporaryDirectory() as tmpdir:
save_rootdisk_nodes(tmpdir)
try:
yield
finally:
restore_rootdisk_nodes(tmpdir)


def ensure_daemon_running_ok(localiqn):
"""Check that the daemon is running and the initiator name is correct"""
if not is_iscsi_daemon_running():
Expand Down
71 changes: 55 additions & 16 deletions tests/test_iscsi.py
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -9,7 +9,7 @@
class Test_iscsi(unittest.TestCase):

@mock.patch('sm.core.iscsi.get_rootdisk_IQNs')
@mock.patch('sm.core.iscsi.util.doexec')
@mock.patch('sm.core.iscsi.util.doexec', return_value=(0, '', ''))
def test_save_rootdisk_nodes(self, doexec, get_rootdisk_iqns):
get_rootdisk_iqns.return_value = [TEST_IQN]

Expand All @@ -20,9 +20,9 @@ def test_save_rootdisk_nodes(self, doexec, get_rootdisk_iqns):
'00.ecd28.mo121',
'/my/safe/tempdir'])

@mock.patch('sm.core.iscsi.util.doexec', return_value=(0, '', ''))
@mock.patch('sm.core.iscsi.get_rootdisk_IQNs')
@mock.patch('sm.core.iscsi.util.doexec')
def test_restore_rootdisk_nodes(self, doexec, get_rootdisk_iqns):
def test_restore_rootdisk_nodes(self, get_rootdisk_iqns, doexec):
get_rootdisk_iqns.return_value = [TEST_IQN]

iscsi.restore_rootdisk_nodes("/my/safe/tempdir")
Expand All @@ -31,25 +31,65 @@ def test_restore_rootdisk_nodes(self, doexec, get_rootdisk_iqns):
'/my/safe/tempdir/iqn.2003-01.com.bla:00.ecd28.mo121',
'/var/lib/iscsi/nodes'])

@mock.patch('sm.core.iscsi._clear_dir')
@mock.patch('sm.core.iscsi.stop_daemon', mock.Mock())
@mock.patch('sm.core.iscsi.exn_on_failure', mock.Mock())
@mock.patch('sm.core.iscsi.util.doexec', mock.Mock())
@mock.patch('sm.core.iscsi.os.path.exists')
@mock.patch('sm.core.iscsi.shutil.rmtree')
def test_restart_daemon(self, rmtree, exists):
exists.return_value = True

@mock.patch('sm.core.iscsi.saved_rootdisk_nodes')
def test_restart_daemon(self, _saved, clear_dir):
"""restart_daemon must clear nodes/ and send_targets/ (keeping the
directories), via _clear_dir, before starting iscsid."""
iscsi.restart_daemon()

rmtree.assert_has_calls([mock.call('/var/lib/iscsi/nodes'),
mock.call('/var/lib/iscsi/send_targets')])

clear_dir.assert_any_call('/var/lib/iscsi/nodes')
clear_dir.assert_any_call('/var/lib/iscsi/send_targets')

@mock.patch('sm.core.iscsi.restart_daemon')
@mock.patch('sm.core.iscsi.set_current_initiator_name')
@mock.patch('sm.core.iscsi.is_iscsi_daemon_running', return_value=False)
def test_ensure_daemon_running_ok_not_running(
self, _is_running, set_iqn, restart):
"""When iscsid is not running, set initiator name and restart."""
iscsi.ensure_daemon_running_ok(TEST_IQN)

set_iqn.assert_called_once_with(TEST_IQN)
restart.assert_called_once()

@mock.patch('sm.core.iscsi.restart_daemon')
@mock.patch('sm.core.iscsi.set_current_initiator_name')
@mock.patch('sm.core.iscsi._checkAnyTGT', return_value=False)
@mock.patch('sm.core.iscsi.get_current_initiator_name', return_value='other-iqn')
@mock.patch('sm.core.iscsi.is_iscsi_daemon_running', return_value=True)
def test_ensure_daemon_running_ok_iqn_mismatch(
self, _is_running, _get_iqn, _check_tgt, set_iqn, restart):
"""IQN mismatch with no non-root sessions: set initiator name and restart."""
iscsi.ensure_daemon_running_ok(TEST_IQN)

set_iqn.assert_called_once_with(TEST_IQN)
restart.assert_called_once()

@mock.patch('sm.core.iscsi.restart_daemon')
@mock.patch('sm.core.iscsi.get_current_initiator_name', return_value=TEST_IQN)
@mock.patch('sm.core.iscsi.is_iscsi_daemon_running', return_value=True)
def test_ensure_daemon_running_ok_no_restart_needed(
self, _is_running, _get_iqn, restart):
"""When iscsid is running with the correct IQN, no restart occurs."""
iscsi.ensure_daemon_running_ok(TEST_IQN)

restart.assert_not_called()

@mock.patch('sm.core.iscsi.restart_daemon', side_effect=Exception("start failed"))
@mock.patch('sm.core.iscsi.set_current_initiator_name')
@mock.patch('sm.core.iscsi.is_iscsi_daemon_running', return_value=False)
def test_ensure_daemon_running_ok_restart_fails_propagates(
self, _is_running, _set_iqn, _restart):
"""If restart_daemon raises, the exception propagates out."""
with self.assertRaises(Exception):
iscsi.ensure_daemon_running_ok(TEST_IQN)

@mock.patch('sm.core.iscsi.util.doexec', mock.Mock())
@mock.patch('sm.core.iscsi.exn_on_failure')
@mock.patch('sm.core.iscsi.tempfile', autospec=True)
@mock.patch('sm.core.iscsi.shutil.rmtree', autospec=True)
def test_discovery_success(self, rmtree, mock_tempfile, mock_exc):
def test_discovery_success(self, mock_tempfile, mock_exc):
mock_exc.return_value = ("test-target,1000 " + TEST_IQN, "")
iscsi.discovery('test-target', 3260, "", "")

Expand All @@ -62,8 +102,7 @@ def test_discovery_success(self, rmtree, mock_tempfile, mock_exc):
@mock.patch('sm.core.iscsi.util.doexec', mock.Mock())
@mock.patch('sm.core.iscsi.exn_on_failure', autospec=True)
@mock.patch('sm.core.iscsi.tempfile', autospec=True)
@mock.patch('sm.core.iscsi.shutil.rmtree', autospec=True)
def test_discovery_chap_success(self, rmtree, mock_tempfile, mock_exc):
def test_discovery_chap_success(self, mock_tempfile, mock_exc):
mock_exc.side_effect = [
("New discovery record for [test-target:3260] added", ""),
("",""),
Expand Down
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