#!/usr/bin/python
+
"""
Picks a host to "create" (boot) a VM on, and does so.
-For now, a very dumb algorithm for which host to boot on:
-the one with fewer machines running.
-
-TODO: load-balance based on something like actual free RAM
+Current load-balancing algorithm: wherever there's more free RAM.
TODO: use a lock to avoid creating the same VM twice in a race
"""
-
+from invirt.remote import bcast
from subprocess import PIPE, Popen, call
import sys
import yaml
-
def choose_host():
# Query each of the hosts.
- # TODO get `servers` from a real list of all the VM hosts (instead of
- # hardcoding the list here)
- servers = ['black-mesa.mit.edu', 'sx-blade-2.mit.edu']
- pipes = [(server,
- Popen(['remctl', server, 'remote', 'web', 'info'], stdout=PIPE))
- for server in servers]
- outputs = [(s, p.communicate()[0]) for (s, p) in pipes]
- for (s, p) in pipes:
- if p.returncode != 0:
- raise RuntimeError("remctl to host %s returned non-zero exit status %d"
- % (s, p.returncode))
- results = [(s, yaml.load(o, yaml.CSafeLoader)) for (s, o) in outputs]
# XXX will the output of 'xm info' always be parseable YAML?
-
- return max( (int(o['free_memory']), s) for (s, o) in results )[1]
-
+ results = bcast('info')
+ return max((int(o['free_memory']), s) for (s, o) in results)[1]
def main(argv):
if len(argv) < 2:
- print >>sys.stderr, "usage: sipb-xen-remote-create <machine> [<other args...>]"
+ print >> sys.stderr, "usage: sipb-xen-remote-create <machine> [<other args...>]"
return 2
machine_name = argv[1]
args = argv[2:]
-
p = Popen(['/usr/sbin/sipb-xen-remote-proxy-web', 'listvms'], stdout=PIPE)
output = p.communicate()[0]
if p.returncode != 0:
if machine_name in vms:
host = vms[machine_name]['host']
- print >>sys.stderr, ("machine '%s' is already running on host %s"
- % (machine_name, host))
+ print >> sys.stderr, ("machine '%s' is already running on host %s"
+ % (machine_name, host))
return 1
-
host = choose_host()
print 'Creating on host %s...' % host
+ sys.stdout.flush()
return call(['remctl', host, 'remote', 'control',
machine_name, 'create'] + args)