196 lines
8.6 KiB
Python
196 lines
8.6 KiB
Python
#!/usr/bin/env python3
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# fencing.py - Utility functions for pvcnoded fencing
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# Part of the Parallel Virtual Cluster (PVC) system
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#
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# Copyright (C) 2018-2021 Joshua M. Boniface <joshua@boniface.me>
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#
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# This program is free software: you can redistribute it and/or modify
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# it under the terms of the GNU General Public License as published by
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# the Free Software Foundation, version 3.
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#
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# This program is distributed in the hope that it will be useful,
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# but WITHOUT ANY WARRANTY; without even the implied warranty of
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# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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# GNU General Public License for more details.
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#
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# You should have received a copy of the GNU General Public License
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# along with this program. If not, see <https://www.gnu.org/licenses/>.
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#
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###############################################################################
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import time
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import daemon_lib.common as common
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from pvcnoded.objects.VMInstance import VMInstance
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#
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# Fence thread entry function
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#
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def fence_node(node_name, zkhandler, config, logger):
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# We allow exactly 6 saving throws (30 seconds) for the host to come back online or we kill it
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failcount_limit = 6
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failcount = 0
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while failcount < failcount_limit:
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# Wait 5 seconds
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time.sleep(config['keepalive_interval'])
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# Get the state
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node_daemon_state = zkhandler.read(('node.state.daemon', node_name))
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# Is it still 'dead'
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if node_daemon_state == 'dead':
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failcount += 1
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logger.out('Node "{}" failed {}/{} saving throws'.format(node_name, failcount, failcount_limit), state='s')
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# It changed back to something else so it must be alive
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else:
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logger.out('Node "{}" passed a saving throw; canceling fence'.format(node_name), state='o')
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return
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logger.out('Fencing node "{}" via IPMI reboot signal'.format(node_name), state='s')
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# Get IPMI information
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ipmi_hostname = zkhandler.read(('node.ipmi.hostname', node_name))
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ipmi_username = zkhandler.read(('node.ipmi.username', node_name))
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ipmi_password = zkhandler.read(('node.ipmi.password', node_name))
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# Shoot it in the head
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fence_status = reboot_via_ipmi(ipmi_hostname, ipmi_username, ipmi_password, logger)
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# Hold to ensure the fence takes effect and system stabilizes
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logger.out('Waiting {}s for fence of node "{}" to take effect'.format(config['keepalive_interval'], node_name), state='i')
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time.sleep(config['keepalive_interval'])
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if fence_status:
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logger.out('Marking node "{}" as fenced'.format(node_name), state='i')
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zkhandler.write([
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(('node.state.daemon', node_name), 'fenced')
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])
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# Force into secondary network state if needed
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if node_name in config['coordinators']:
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logger.out('Forcing secondary status for node "{}"'.format(node_name), state='i')
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zkhandler.write([
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(('node.state.router', node_name), 'secondary')
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])
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if zkhandler.read('base.config.primary_node') == node_name:
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zkhandler.write([
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('base.config.primary_node', 'none')
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])
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# If the fence succeeded and successful_fence is migrate
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if fence_status and config['successful_fence'] == 'migrate':
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migrateFromFencedNode(zkhandler, node_name, config, logger)
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# If the fence failed and failed_fence is migrate
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if not fence_status and config['failed_fence'] == 'migrate' and config['suicide_intervals'] != '0':
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migrateFromFencedNode(zkhandler, node_name, config, logger)
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# Migrate hosts away from a fenced node
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def migrateFromFencedNode(zkhandler, node_name, config, logger):
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logger.out('Migrating VMs from dead node "{}" to new hosts'.format(node_name), state='i')
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# Get the list of VMs
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dead_node_running_domains = zkhandler.read(('node.running_domains', node_name)).split()
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# Set the node to a custom domainstate so we know what's happening
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zkhandler.write([
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(('node.state.domain', node_name), 'fence-flush')
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])
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# Migrate a VM after a flush
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def fence_migrate_vm(dom_uuid):
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VMInstance.flush_locks(zkhandler, logger, dom_uuid)
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target_node = common.findTargetNode(zkhandler, dom_uuid)
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if target_node is not None:
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logger.out('Migrating VM "{}" to node "{}"'.format(dom_uuid, target_node), state='i')
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zkhandler.write([
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(('domain.state', dom_uuid), 'start'),
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(('domain.node', dom_uuid), target_node),
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(('domain.last_node', dom_uuid), node_name),
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])
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else:
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logger.out('No target node found for VM "{}"; VM will autostart on next unflush/ready of current node'.format(dom_uuid), state='i')
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zkhandler.write({
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(('domain.state', dom_uuid), 'stopped'),
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(('domain.meta.autostart', dom_uuid), 'True'),
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})
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# Loop through the VMs
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for dom_uuid in dead_node_running_domains:
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fence_migrate_vm(dom_uuid)
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# Set node in flushed state for easy remigrating when it comes back
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zkhandler.write([
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(('node.state.domain', node_name), 'flushed')
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])
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logger.out('All VMs flushed from dead node "{}" to new hosts'.format(node_name), state='i')
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#
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# Perform an IPMI fence
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#
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def reboot_via_ipmi(ipmi_hostname, ipmi_user, ipmi_password, logger):
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# Forcibly reboot the node
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ipmi_command_reset = '/usr/bin/ipmitool -I lanplus -H {} -U {} -P {} chassis power reset'.format(
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ipmi_hostname, ipmi_user, ipmi_password
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)
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ipmi_reset_retcode, ipmi_reset_stdout, ipmi_reset_stderr = common.run_os_command(ipmi_command_reset)
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if ipmi_reset_retcode != 0:
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logger.out(f'Failed to reboot dead node: {ipmi_reset_stderr}', state='e')
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time.sleep(1)
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# Power on the node (just in case it is offline)
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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
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)
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ipmi_start_retcode, ipmi_start_stdout, ipmi_start_stderr = common.run_os_command(ipmi_command_start)
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time.sleep(2)
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# Check the chassis power state
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logger.out('Checking power state of dead node', state='i')
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ipmi_command_status = '/usr/bin/ipmitool -I lanplus -H {} -U {} -P {} chassis power status'.format(
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ipmi_hostname, ipmi_user, ipmi_password
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)
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ipmi_status_retcode, ipmi_status_stdout, ipmi_status_stderr = common.run_os_command(ipmi_command_status)
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if ipmi_reset_retcode == 0:
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if ipmi_status_stdout.strip() == "Chassis Power is on":
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# We successfully rebooted the node and it is powered on; this is a succeessful fence
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logger.out('Successfully rebooted dead node', state='o')
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return True
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elif ipmi_status_stdout.strip() == "Chassis Power is off":
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# We successfully rebooted the node but it is powered off; this might be expected or not, but the node is confirmed off so we can call it a successful fence
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logger.out('Chassis power is in confirmed off state after successfuly IPMI reboot; proceeding with fence-flush', state='o')
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return True
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else:
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# We successfully rebooted the node but it is in some unknown power state; since this might indicate a silent failure, we must call it a failed fence
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logger.out('Chassis power is in an unknown state ({}) after successful IPMI reboot; not performing fence-flush'.format(ipmi_status_stdout.strip()), state='e')
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return False
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else:
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if ipmi_status_stdout.strip() == "Chassis Power is off":
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# We failed to reboot the node but it is powered off; it has probably suffered a serious hardware failure, but the node is confirmed off so we can call it a successful fence
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logger.out('Chassis power is in confirmed off state after failed IPMI reboot; proceeding with fence-flush', state='o')
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return True
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else:
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# We failed to reboot the node but it is in some unknown power state (including "on"); since this might indicate a silent failure, we must call it a failed fence
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logger.out('Chassis power is not in confirmed off state after failed IPMI reboot; not performing fence-flush', state='e')
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return False
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#
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# Verify that IPMI connectivity to this host exists (used during node init)
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#
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def verify_ipmi(ipmi_hostname, ipmi_user, ipmi_password):
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ipmi_command = f'/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power status'
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retcode, stdout, stderr = common.run_os_command(ipmi_command, timeout=2)
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if retcode == 0 and stdout.strip() == "Chassis Power is on":
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return True
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else:
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return False
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