from collections import Counter from functools import reduce import bitmath from ucloud.common.host import HostStatus from ucloud.common.request import RequestEntry, RequestType from ucloud.common.vm import VMStatus from ucloud.config import vm_pool, host_pool, request_pool, config 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) for component in _vms_specs: if isinstance(_vms_specs[component], str): _vms_specs[component] = int(bitmath.parse_string_unsafe(_vms_specs[component]).to_MB()) elif isinstance(_vms_specs[component], list): _vms_specs[component] = map(lambda x: int(bitmath.parse_string_unsafe(x).to_MB()), _vms_specs[component]) _vms_specs[component] = reduce(lambda x, y: x + y, _vms_specs[component], 0) for component in _remaining: if isinstance(_remaining[component], str): _remaining[component] = int(bitmath.parse_string_unsafe(_remaining[component]).to_MB()) elif isinstance(_remaining[component], list): _remaining[component] = map(lambda x: int(bitmath.parse_string_unsafe(x).to_MB()), _remaining[component]) _remaining[component] = reduce(lambda x, y: x + y, _remaining[component], 0) _remaining.subtract(_vms_specs) return _remaining class NoSuitableHostFound(Exception): """Exception when no host found that can host a VM.""" 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.by_status(VMStatus.running, 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 all(map(lambda x: x >= 0, remaining.values())): return host.key raise NoSuitableHostFound 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): vm.hostname = get_suitable_host(vm.specs) vm_pool.put(vm) r = RequestEntry.from_scratch(type=RequestType.StartVM, uuid=vm.uuid, hostname=vm.hostname, request_prefix=config['etcd']['REQUEST_PREFIX']) request_pool.put(r) vm.log.append("VM scheduled for starting") return vm.hostname