pvc/node-daemon/pvcd/fencing.py

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#!/usr/bin/env python3
# fencing.py - PVC daemon function library, node fencing functions
# Part of the Parallel Virtual Cluster (PVC) system
#
# Copyright (C) 2018 Joshua M. Boniface <joshua@boniface.me>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
###############################################################################
import time
import threading
import pvcd.zkhandler as zkhandler
import pvcd.common as common
#
# Fence thread entry function
#
def fenceNode(node_name, zk_conn, config, logger):
failcount = 0
# We allow exactly 3 saving throws for the host to come back online
while failcount < 3:
# Wait 5 seconds
time.sleep(5)
# Get the state
node_daemon_state = zkhandler.readdata(zk_conn, '/nodes/{}/daemonstate'.format(node_name))
# Is it still 'dead'
if node_daemon_state == 'dead':
failcount += 1
logger.out('Node "{}" failed {} saving throws'.format(node_name, failcount), state='w')
# It changed back to something else so it must be alive
else:
logger.out('Node "{}" passed a saving throw; canceling fence'.format(node_name), state='o')
return
logger.out('Fencing node "{}" via IPMI reboot signal'.format(node_name), state='w')
# Get IPMI information
ipmi_hostname = zkhandler.readdata(zk_conn, '/nodes/{}/ipmihostname'.format(node_name))
ipmi_username = zkhandler.readdata(zk_conn, '/nodes/{}/ipmiusername'.format(node_name))
ipmi_password = zkhandler.readdata(zk_conn, '/nodes/{}/ipmipassword'.format(node_name))
# Shoot it in the head
fence_status = rebootViaIPMI(ipmi_hostname, ipmi_username, ipmi_password, logger)
# Hold to ensure the fence takes effect
time.sleep(3)
# Force into secondary network state if needed
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if node_name in config['coordinators']:
zkhandler.writedata(zk_conn, { '/nodes/{}/routerstate'.format(node_name): 'secondary' })
if zkhandler.readdata(zk_conn, '/primary_node') == node_name:
zkhandler.writedata(zk_conn, { '/primary_node': 'none' })
# If the fence succeeded and successful_fence is migrate
if fence_status == True and config['successful_fence'] == 'migrate':
migrateFromFencedNode(zk_conn, node_name, logger)
# If the fence failed and failed_fence is migrate
if fence_status == False and config['failed_fence'] == 'migrate' and config['suicide_intervals'] != '0':
migrateFromFencedNode(zk_conn, node_name, logger)
# Migrate hosts away from a fenced node
def migrateFromFencedNode(zk_conn, node_name, logger):
logger.out('Migrating VMs from dead node "{}" to new hosts'.format(node_name), state='i')
dead_node_running_domains = zkhandler.readdata(zk_conn, '/nodes/{}/runningdomains'.format(node_name)).split()
for dom_uuid in dead_node_running_domains:
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logger.out('Flushing RBD locks for VM "{}"'.format(dom_uuid), state='i')
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# Get the list of RBD images
rbd_list = zkhandler.readdata(zk_conn, '/domains/{}/rbdlist'.format(dom_uuid)).split(',')
for rbd in rbd_list:
# Check if a lock exists
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lock_list_retcode, lock_list_stdout, lock_list_stderr = common.run_os_command('rbd lock list --format json {}'.format(rbd))
if lock_list_retcode != 0:
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logger.out('Failed to obtain lock list for volume "{}"'.format(rbd), state='e')
continue
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try:
lock_list = json.loads(lock_list_stdout)
except:
lock_list = {}
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# If there's at least one lock
if lock_list:
# Loop through the locks
for lock, detail in lock_list.items():
# Free the lock
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lock_remove_retcode, lock_remove_stdout, lock_remove_stderr = common.run_os_command('rbd lock remove {} "{}" "{}"'.format(rbd, lock, detail['locker']))
if lock_remove_retcode != 0:
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logger.out('Failed to free RBD lock "{}" on volume "{}"'.format(lock, rbd), state='e')
continue
logger.out('Freed RBD lock "{}" on volume "{}"'.format(lock, rbd), state='o')
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target_node = common.findTargetHypervisor(zk_conn, 'mem', dom_uuid)
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logger.out('Migrating VM "{}" to node "{}"'.format(dom_uuid, target_node), state='i')
zkhandler.writedata(zk_conn, {
'/domains/{}/state'.format(dom_uuid): 'start',
'/domains/{}/node'.format(dom_uuid): target_node,
'/domains/{}/lastnode'.format(dom_uuid): node_name
})
# Set node in flushed state for easy remigrating when it comes back
zkhandler.writedata(zk_conn, { '/nodes/{}/domainstate'.format(node_name): 'flushed' })
#
# Perform an IPMI fence
#
def rebootViaIPMI(ipmi_hostname, ipmi_user, ipmi_password, logger):
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# Forcibly reboot the node
ipmi_command_reset = '/usr/bin/ipmitool -I lanplus -H {} -U {} -P {} chassis power reset'.format(
ipmi_hostname, ipmi_user, ipmi_password
)
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ipmi_reset_retcode, ipmi_reset_stdout, ipmi_reset_stderr = common.run_os_command(ipmi_command_reset)
time.sleep(2)
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# Ensure the node is powered on
ipmi_command_status = '/usr/bin/ipmitool -I lanplus -H {} -U {} -P {} chassis power status'.format(
ipmi_hostname, ipmi_user, ipmi_password
)
ipmi_status_retcode, ipmi_status_stdout, ipmi_status_stderr = common.run_os_command(ipmi_command_status)
# Trigger a power start if needed
if ipmi_status_stdout != "Chassis Power is on":
ipmi_command_start = '/usr/bin/ipmitool -I lanplus -H {} -U {} -P {} chassis power on'.format(
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ipmi_hostname, ipmi_user, ipmi_password
)
ipmi_start_retcode, ipmi_start_stdout, ipmi_start_stderr = common.run_os_command(ipmi_command_start)
# Declare success or failure
if ipmi_reset_retcode == 0:
logger.out('Successfully rebooted dead node', state='o')
return True
else:
logger.out('Failed to reboot dead node', state='e')
print(ipmi_reset_stderr)
return False