ucloud-scheduler/helper.py

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from collections import Counter
from functools import reduce
from ucloud_common.vm import VmPool, VMStatus
from ucloud_common.host import HostPool, HostStatus
from ucloud_common.request import RequestEntry, RequestPool, RequestType
from decouple import config
2019-09-03 16:06:41 +00:00
from config import etcd_client as client
vm_pool = VmPool(client, config("VM_PREFIX"))
host_pool = HostPool(client, config("HOST_PREFIX"))
request_pool = RequestPool(client, config("REQUEST_PREFIX"))
def accumulated_specs(vms_specs):
if not vms_specs:
return {}
return reduce((lambda x, y: Counter(x) + Counter(y)), vms_specs)
def remaining_resources(host_specs, vms_specs):
"""Return remaining resources host_specs - vms"""
vms_specs = Counter(vms_specs)
remaining = Counter(host_specs)
remaining.subtract(vms_specs)
return remaining
def get_suitable_host(vm_specs, hosts=None):
if hosts is None:
hosts = host_pool.by_status(HostStatus.alive)
for host in hosts:
# Filter them by host_name
vms = vm_pool.by_host(host.key)
# Filter them by status
vms = vm_pool.except_status(VMStatus.requested_new, vms)
running_vms_specs = [vm.specs for vm in vms]
# Accumulate all of their combined specs
running_vms_accumulated_specs = accumulated_specs(
running_vms_specs
)
# Find out remaining resources after
# host_specs - already running vm_specs
remaining = remaining_resources(
host.specs, running_vms_accumulated_specs
)
# Find out remaining - new_vm_specs
remaining = remaining_resources(remaining, vm_specs)
# if remaining resources >= 0 return this host_name
if all(
map(
lambda x: True if remaining[x] >= 0 else False,
remaining,
)
):
return host.key
return None
def dead_host_detection():
# Bring out your dead! - Monty Python and the Holy Grail
hosts = host_pool.by_status(HostStatus.alive)
dead_hosts_keys = []
for host in hosts:
# Only check those who claims to be alive
if host.status == HostStatus.alive:
if not host.is_alive():
dead_hosts_keys.append(host.key)
return dead_hosts_keys
def dead_host_mitigation(dead_hosts_keys):
for host_key in dead_hosts_keys:
host = host_pool.get(host_key)
host.declare_dead()
vms_hosted_on_dead_host = vm_pool.by_host(host_key)
for vm in vms_hosted_on_dead_host:
vm.declare_killed()
vm_pool.put(vm)
host_pool.put(host)
def assign_host(vm):
host_name = get_suitable_host(vm.specs)
if host_name:
# if vm.status == VMStatus.requested_new:
# vm.status = VMStatus.scheduled_deploy
#
# if vm.status == VMStatus.killed:
# vm.status = VMStatus.requested_start
vm.hostname = host_name
vm_pool.put(vm)
r = RequestEntry.from_scratch(type=RequestType.StartVM,
uuid=vm.uuid,
hostname=vm.hostname)
request_pool.put(r)
vm.log.append("VM scheduled for starting")
return host_name
return None