def volume_set_of(image):
"""
:return: the set of data volumes defined for the given Docker image
"""
cmd = ['docker', 'inspect', image]
vols = yaml.load(subprocess.check_output(print_args(cmd)))[0]['Config']['Volumes']
return set(vols.keys()) if vols else None
def create_loader_container(loader_image, tag):
# N.B. this name must be consistent with the definition in cloud-config.yml.jinja
container = "loader-{}".format(tag)
if not has_container(container):
# Retrieve runtime parameters from the current loader and reuse them for the new loader.
inspect = yaml.load(subprocess.check_output(['docker', 'inspect', my_container_id()]))
cmd = ['docker', 'create', '--name', container]
for bind in inspect[0]['HostConfig']['Binds']:
cmd.append('-v')
cmd.append(bind)
cmd.append(loader_image)
cmd.extend(inspect[0]['Config']['Cmd'])
subprocess.check_call(print_args(cmd))
return container
def gc():
# TODO currently GC don't perform cleaning for loader images of the same tag but different repo names than the
# current loader.
subprocess.check_call(print_args(['/gc.sh', my_image_name(), _tag]))
return ''
def has_container(container):
with open(devnull, 'w') as null:
return subprocess.call(print_args(['docker', 'inspect', container]), stdout=null, stderr=null) == 0
def switch(repo, tag, target):
kill_other_containers()
print 'Computing data volumes to be copied from the old containers...'
# List old containers
# old: map of original-name => (old modified-name, image)
old = {}
with open(MODIFIED_YML_PATH) as f:
for k, v in yaml.load(f)['containers'].iteritems():
old[v['original-name']] = (k, v['image'])
# List the new containers that haven't been created and have shared volumes with their old counterparts.
# new: map of new modified-name => (old modified-name, volumes shared by both old and new containers)
new = {}
new_loader_image = '{}/{}:{}'.format(repo, my_image_name(), tag)
cmd = ['docker', 'run', '--rm', '-v', '/var/run/docker.sock:/var/run/docker.sock', new_loader_image, 'modified-yml',
repo, tag]
for new_container, new_container_props in yaml.load(subprocess.check_output(print_args(cmd)))['containers'].iteritems():
counterpart = old.get(new_container_props['original-name'])
if not counterpart:
print '{} has no counterpart'.format(new_container)
continue
volumes = volume_set_of(new_container_props['image'])
if not volumes:
print '{} has no data volumes'.format(new_container)
continue
counterpart_volumes = volume_set_of(counterpart[1])
if not counterpart_volumes:
print '{}\'s counterpart has no data volumes'.format(new_container)
continue
intersected_volumes = volumes & counterpart_volumes
if not counterpart_volumes:
print '{} has no intersecting data volumes'.format(new_container)
continue
if has_container(new_container):
print '{} already exists'.format(new_container)
continue
if not has_container(counterpart[0]):
print '{} doesn\'t exist'.format(counterpart[0])
continue
new[new_container] = (counterpart[0], intersected_volumes)
print 'Containers for data copying, in the format of "target-container: (source-container, volumes)":'
print new
# Create the loader container first. Otherwise when launching the containers that we create below, the system would
# fail if one of them links to the new loader -- the `create-containers` command doesn't create the loader.
new_loader = create_loader_container(new_loader_image, tag)
if new:
# Create containers
cmd = ['docker', 'run', '--rm', '-v', '/var/run/docker.sock:/var/run/docker.sock', new_loader_image,
'create-containers', repo, tag, new_loader]
cmd.extend(new.keys())
subprocess.check_call(print_args(cmd))
# Copy data
loader_image = my_full_image_name()
for container, new_container_props in new.iteritems():
cmd = ['/copy-container-data.sh', loader_image, new_container_props[0], container]
cmd.extend(list(new_container_props[1]))
subprocess.check_call(print_args(cmd))
with open(_repo_file, 'w') as f:
f.write(repo)
with open(_tag_file, 'w') as f:
f.write(tag)
return restart_to(target)
