pvc/health-daemon/pvchealthd/util/fencing.py

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#!/usr/bin/env python3
# fencing.py - Utility functions for pvcnoded fencing
# Part of the Parallel Virtual Cluster (PVC) system
#
# Copyright (C) 2018-2022 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, version 3.
#
# 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 daemon_lib.common as common
from daemon_lib.vm import vm_worker_flush_locks
#
# Fence thread entry function
#
def fence_node(node_name, zkhandler, config, logger):
# We allow exactly 6 saving throws (30 seconds) for the host to come back online or we kill it
failcount_limit = 6
failcount = 0
while failcount < failcount_limit:
# Wait 5 seconds
time.sleep(config["keepalive_interval"])
# Get the state
node_daemon_state = zkhandler.read(("node.state.daemon", node_name))
# Is it still 'dead'
if node_daemon_state == "dead":
failcount += 1
logger.out(
f"Node {node_name} failed {failcount}/{failcount_limit} saving throws",
state="s",
prefix=f"fencing {node_name}",
)
# It changed back to something else so it must be alive
else:
logger.out(
f"Node {node_name} passed a saving throw; cancelling fance",
state="o",
prefix=f"fencing {node_name}",
)
return
logger.out(
f"Fencing node {node_name} via IPMI reboot signal",
state="s",
prefix=f"fencing {node_name}",
)
# Get IPMI information
ipmi_hostname = zkhandler.read(("node.ipmi.hostname", node_name))
ipmi_username = zkhandler.read(("node.ipmi.username", node_name))
ipmi_password = zkhandler.read(("node.ipmi.password", node_name))
# Shoot it in the head
fence_status = reboot_via_ipmi(
node_name, ipmi_hostname, ipmi_username, ipmi_password, logger
)
# Hold to ensure the fence takes effect and system stabilizes
logger.out(
f"Waiting {config['keepalive_interval']}s for fence of node {node_name} to take effect",
state="i",
prefix=f"fencing {node_name}",
)
time.sleep(config["keepalive_interval"])
if fence_status:
logger.out(
f"Marking node {node_name} as fenced",
state="i",
prefix=f"fencing {node_name}",
)
while True:
try:
zkhandler.write([(("node.state.daemon", node_name), "fenced")])
break
except Exception:
continue
# Force into secondary network state if needed
if node_name in config["coordinators"]:
logger.out(
f"Forcing secondary coordinator state for node {node_name}",
state="i",
prefix=f"fencing {node_name}",
)
zkhandler.write([(("node.state.router", node_name), "secondary")])
if zkhandler.read("base.config.primary_node") == node_name:
zkhandler.write([("base.config.primary_node", "none")])
# If the fence succeeded and successful_fence is migrate
if fence_status and config["successful_fence"] == "migrate":
migrateFromFencedNode(zkhandler, node_name, config, logger)
# If the fence failed and failed_fence is migrate
if (
not fence_status
and config["failed_fence"] == "migrate"
and config["suicide_intervals"] != "0"
):
migrateFromFencedNode(zkhandler, node_name, config, logger)
# Migrate hosts away from a fenced node
def migrateFromFencedNode(zkhandler, node_name, config, logger):
logger.out(
f"Migrating VMs from dead node {node_name} to new hosts",
state="i",
prefix=f"fencing {node_name}",
)
# Get the list of VMs
dead_node_running_domains = zkhandler.read(
("node.running_domains", node_name)
).split()
# Set the node to a custom domainstate so we know what's happening
zkhandler.write([(("node.state.domain", node_name), "fence-flush")])
# Migrate a VM after a flush
def fence_migrate_vm(dom_uuid):
logger.out(
f"Flushing locks of VM {dom_uuid} due to fence",
state="i",
prefix=f"fencing {node_name}",
)
vm_worker_flush_locks(zkhandler, None, dom_uuid, force_unlock=True)
target_node = common.findTargetNode(zkhandler, dom_uuid)
if target_node is not None:
logger.out(
f"Migrating VM {dom_uuid} to node {target_node}",
state="i",
prefix=f"fencing {node_name}",
)
zkhandler.write(
[
(("domain.state", dom_uuid), "start"),
(("domain.node", dom_uuid), target_node),
(("domain.last_node", dom_uuid), node_name),
]
)
logger.out(
f"Successfully migrated running VM {dom_uuid} to node {target_node}",
state="o",
prefix=f"fencing {node_name}",
)
else:
logger.out(
f"No target node found for VM {dom_uuid}; marking autostart=True on current node",
state="i",
prefix=f"fencing {node_name}",
)
zkhandler.write(
{
(("domain.state", dom_uuid), "stopped"),
(("domain.meta.autostart", dom_uuid), "True"),
}
)
logger.out(
f"Successfully marked autostart for running VM {dom_uuid} on current node",
state="o",
prefix=f"fencing {node_name}",
)
# Loop through the VMs
for dom_uuid in dead_node_running_domains:
try:
fence_migrate_vm(dom_uuid)
except Exception as e:
logger.out(
f"Failed to migrate VM {dom_uuid}, continuing: {e}",
state="w",
prefix=f"fencing {node_name}",
)
# Set node in flushed state for easy remigrating when it comes back
zkhandler.write([(("node.state.domain", node_name), "flushed")])
logger.out(
f"All VMs flushed from dead node {node_name} to other nodes",
state="i",
prefix=f"fencing {node_name}",
)
#
# Perform an IPMI fence
#
def reboot_via_ipmi(node_name, ipmi_hostname, ipmi_user, ipmi_password, logger):
# Power off the node the node
logger.out(
"Sending power off to dead node",
state="i",
prefix=f"fencing {node_name}",
)
ipmi_stop_retcode, ipmi_stop_stdout, ipmi_stop_stderr = common.run_os_command(
f"/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power off"
)
if ipmi_stop_retcode != 0:
logger.out(
f"Failed to power off dead node: {ipmi_stop_stderr}",
state="e",
prefix=f"fencing {node_name}",
)
logger.out(
"Waiting 5s for power off to take effect",
state="i",
prefix=f"fencing {node_name}",
)
time.sleep(5)
# Check the chassis power state
logger.out(
"Checking power state of dead node",
state="i",
prefix=f"fencing {node_name}",
)
ipmi_status_retcode, ipmi_status_stdout, ipmi_status_stderr = common.run_os_command(
f"/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power status"
)
if ipmi_status_retcode == 0:
logger.out(
f"Current chassis power state is: {ipmi_status_stdout.strip()}",
state="i",
prefix=f"fencing {node_name}",
)
else:
logger.out(
"Current chassis power state is: Unknown",
state="w",
prefix=f"fencing {node_name}",
)
# Power on the node
logger.out(
"Sending power on to dead node",
state="i",
prefix=f"fencing {node_name}",
)
ipmi_start_retcode, ipmi_start_stdout, ipmi_start_stderr = common.run_os_command(
f"/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power on"
)
if ipmi_start_retcode != 0:
logger.out(
f"Failed to power on dead node: {ipmi_start_stderr}",
state="w",
prefix=f"fencing {node_name}",
)
logger.out(
"Waiting 2s for power on to take effect",
state="i",
prefix=f"fencing {node_name}",
)
time.sleep(2)
# Check the chassis power state
logger.out(
"Checking power state of dead node",
state="i",
prefix=f"fencing {node_name}",
)
ipmi_status_retcode, ipmi_status_stdout, ipmi_status_stderr = common.run_os_command(
f"/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power status"
)
if ipmi_stop_retcode == 0:
if ipmi_status_stdout.strip() == "Chassis Power is on":
# We successfully rebooted the node and it is powered on; this is a succeessful fence
logger.out(
"Successfully rebooted dead node; proceeding with fence recovery action",
state="o",
prefix=f"fencing {node_name}",
)
return True
elif ipmi_status_stdout.strip() == "Chassis Power is off":
# 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
logger.out(
"Chassis power is in confirmed off state after successfuly IPMI reboot; proceeding with fence recovery action",
state="o",
prefix=f"fencing {node_name}",
)
return True
else:
# 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
logger.out(
f"Chassis power is in an unknown state ({ipmi_status_stdout.strip()}) after successful IPMI reboot; NOT proceeding fence recovery action",
state="e",
prefix=f"fencing {node_name}",
)
return False
else:
if ipmi_status_stdout.strip() == "Chassis Power is off":
# 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
logger.out(
"Chassis power is in confirmed off state after failed IPMI reboot; proceeding with fence recovery action",
state="o",
prefix=f"fencing {node_name}",
)
return True
else:
# 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
logger.out(
"Chassis power is not in confirmed off state after failed IPMI reboot; NOT proceeding wiht fence recovery action",
state="e",
prefix=f"fencing {node_name}",
)
return False
#
# Verify that IPMI connectivity to this host exists (used during node init)
#
def verify_ipmi(ipmi_hostname, ipmi_user, ipmi_password):
ipmi_command = f"/usr/bin/ipmitool -I lanplus -H {ipmi_hostname} -U {ipmi_user} -P {ipmi_password} chassis power status"
retcode, stdout, stderr = common.run_os_command(ipmi_command, timeout=2)
if retcode == 0 and stdout.strip() == "Chassis Power is on":
return True
else:
return False