#
# Copyright 2014 Red Hat, Inc.
#
# 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; either version 2 of the License, or
# (at your option) any later version.
#
# 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, write to the Free Software
# Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
#
# Refer to the README and COPYING files for full details of the license
#
import copy
import json
import logging
import os
import shutil
import uuid
import paths
import subnet_lease
import utils
import virt
[docs]def _create_ip(subnet, index):
"""
Given a subnet or an ip and an index returns the ip with that lower index
from the subnet (255.255.255.0 mask only subnets)
Args:
subnet (str): Strign containing the three first elements of the decimal
representation of a subnet (X.Y.Z) or a full ip (X.Y.Z.A)
index (int or str): Last element of a decimal ip representation, for
example, 123 for the ip 1.2.3.123
Returns:
str: The dotted decimal representation of the ip
"""
return '.'.join(subnet.split('.')[:3] + [str(index)])
[docs]def _ip_in_subnet(subnet, ip):
"""
Checks if an ip is included in a subnet.
Note:
only 255.255.255.0 masks allowed
Args:
subnet (str): Strign containing the three first elements of the decimal
representation of a subnet (X.Y.Z) or a full ip (X.Y.Z.A)
ip (str or int): Decimal ip representation
Returns:
bool: ``True`` if ip is in subnet, ``False`` otherwise
"""
return (
_create_ip(subnet, 1) == _create_ip(ip, 1)
or
'0.0.0.1' == _create_ip(ip, 1)
)
[docs]class Prefix(object):
"""
A prefix is a directory that will contain all the data needed to setup the
environment.
Attributes:
_prefix (str): Path to the directory of this prefix
_paths (lago.path.Paths): Path handler class
_virt_env (lago.virt.VirtEnv): Lazily loaded virtual env handler
_metadata (dict): Lazily loaded metadata
"""
def __init__(self, prefix):
"""
Args:
prefix (str): Path of the prefix
"""
self._prefix = prefix
self._paths = self._create_paths()
self._virt_env = None
self._metadata = None
[docs] def _create_paths(self):
"""
Get the path handler for this instance
Returns:
lago.paths.Paths: Path handler
"""
return paths.Paths(self._prefix)
[docs] def save(self):
"""
Save this prefix to persistent storage
Returns:
None
"""
self._save_metadata()
self.virt_env.save()
@property
def paths(self):
"""
Access the path handler for this prefix
Returns:
lago.paths.Paths: Path handler
"""
return self._paths
[docs] def _create_ssh_keys(self):
"""
Generate a pair of ssh keys for this prefix
Returns:
None
Raises:
RuntimeError: if it fails to create the keys
"""
ret, _, _ = utils.run_command(
[
'ssh-keygen',
'-t', 'rsa',
'-N', '',
'-f', self.paths.ssh_id_rsa(),
]
)
if ret != 0:
raise RuntimeError(
'Failed to crate ssh keys at %s',
self.paths.ssh_id_rsa(),
)
[docs] def initialize(self):
"""
Initialize this prefix, this includes creating the destination path,
and creating the uuid for the prefix, for any other actions see
:func:`Prefix.virt_conf`
Will safely roll back if any of those steps fail
Returns:
None
Raises:
RuntimeError: If it fails to create the prefix dir
"""
prefix = self.paths.prefix()
with utils.RollbackContext() as rollback:
try:
os.mkdir(prefix)
except OSError:
raise RuntimeError('Could not create prefix at %s' % prefix)
rollback.prependDefer(shutil.rmtree, prefix)
with open(self.paths.uuid(), 'w') as f:
f.write(uuid.uuid1().hex)
with open(self.paths.prefix_lagofile(), 'w') as f:
f.write('')
self._create_ssh_keys()
rollback.clear()
[docs] def cleanup(self):
"""
Stops any running entities in the prefix and uninitializes it, usually
you want to do this if you are going to remove the prefix afterwards
Returns:
None
"""
logging.info("Cleaning up prefix")
self.stop()
logging.info("Tagging prefix as uninitialized")
os.unlink(self.paths.prefix_lagofile())
logging.info("Done")
[docs] def _init_net_specs(self, conf):
"""
Given a configuration specification, initializes all the net
definitions in it so they can be used comfortably
Args:
conf (dict): Configuration specification
Returns:
None
"""
for net_name, net_spec in conf.get('nets', {}).items():
net_spec['name'] = net_name
net_spec['mapping'] = {}
net_spec.setdefault('type', 'nat')
[docs] def _check_predefined_subnets(self, conf):
"""
Checks if all of the nets defined in the config are inside the allowed
range, throws exception if not
Args:
conf (dict): Configuration spec where to get the nets definitions
from
Returns:
None
Raises:
RuntimeError: If there are any subnets out of the allowed range
"""
for net_name, net_spec in conf.get('nets', {}).items():
subnet = net_spec.get('gw')
if subnet is None:
continue
if subnet_lease.is_leasable_subnet(subnet):
raise RuntimeError(
'%s subnet can only be dynamically allocated' % (subnet)
)
[docs] def _allocate_subnets(self, conf):
"""
Allocate all the subnets needed by the given configuration spec
Args:
conf (dict): Configuration spec where to get the nets definitions
from
Returns:
list: allocated subnets
"""
allocated_subnets = []
try:
for net_name, net_spec in conf.get('nets', {}).items():
if 'gw' in net_spec or net_spec['type'] != 'nat':
continue
net_spec['gw'] = subnet_lease.acquire(self.paths.uuid())
allocated_subnets.append(net_spec['gw'])
except:
for subnet in allocated_subnets:
subnet_lease.release(subnet)
return allocated_subnets
[docs] def _add_nic_to_mapping(self, net, dom, nic):
"""
Populates the given net spec mapping entry with the nicks of the given
domain
Args:
net (dict): Network spec to populate
dom (dict): libvirt domain specification
nic (str): Name of the interface to add to the net mapping from the
domain
Returns:
None
"""
dom_name = dom['name']
idx = dom['nics'].index(nic)
name = idx == 0 and dom_name or '%s-eth%d' % (dom_name, idx)
net['mapping'][name] = nic['ip']
[docs] def _register_preallocated_ips(self, conf):
"""
Parse all the domains in the given conf and preallocate all their ips
into the networks mappings, raising exception on duplicated ips or ips
out of the allowed ranges
See Also:
:mod:`lago.subnet_lease`
Args:
conf (dict): Configuration spec to parse
Returns:
None
Raises:
RuntimeError: if there are any duplicated ips or any ip out of the
allowed range
"""
for dom_name, dom_spec in conf.get('domains', {}).items():
for idx, nic in enumerate(dom_spec.get('nics', [])):
if 'ip' not in nic:
continue
net = conf['nets'][nic['net']]
if subnet_lease.is_leasable_subnet(net['gw']):
nic['ip'] = _create_ip(
net['gw'],
int(nic['ip'].split('.')[-1])
)
dom_name = dom_spec['name']
if not _ip_in_subnet(net['gw'], nic['ip']):
raise RuntimeError(
"%s:nic%d's IP [%s] is outside the subnet [%s]",
dom_name,
dom_spec['nics'].index(nic),
nic['ip'],
net['gw'],
)
if nic['ip'] in net['mapping'].values():
conflict_list = [
name for name, ip in net['mapping'].items()
if ip == net['ip']
]
raise RuntimeError(
'IP %s was to several domains: %s %s' % (
nic['ip'],
dom_name,
' '.join(conflict_list),
),
)
self._add_nic_to_mapping(net, dom_spec, nic)
[docs] def _allocate_ips_to_nics(self, conf):
"""
For all the nics of all the domains in the conf that have dynamic ip,
allocate one and addit to the network mapping
Args:
conf (dict): Configuration spec to extract the domains from
Returns:
None
"""
for dom_name, dom_spec in conf.get('domains', {}).items():
for idx, nic in enumerate(dom_spec.get('nics', [])):
if 'ip' in nic:
continue
net = conf['nets'][nic['net']]
if net['type'] != 'nat':
continue
allocated = net['mapping'].values()
vacant = _create_ip(
net['gw'],
set(range(2, 255)).difference(
set(
[
int(ip.split('.')[-1]) for ip in allocated
]
)
).pop()
)
nic['ip'] = vacant
self._add_nic_to_mapping(net, dom_spec, nic)
[docs] def _config_net_topology(self, conf):
"""
Initialize and populate all the network related elements, like
reserving ips and populating network specs of the given confiiguration
spec
Args:
conf (dict): Configuration spec to initalize
Returns:
None
"""
self._init_net_specs(conf)
self._check_predefined_subnets(conf)
allocated_subnets = self._allocate_subnets(conf)
try:
self._register_preallocated_ips(conf)
self._allocate_ips_to_nics(conf)
except:
for subnet in allocated_subnets:
subnet_lease.release(subnet)
raise
[docs] def _create_disk(
self,
name,
spec,
template_repo=None,
template_store=None,
):
"""
Creates a disc with the given name from the given repo or store.
Args:
name (str): Name of the domain to create the disk for
spec (dict): Specification of the disk to create
template_repo (TemplateRepository or None): template repo instance
to use
template_store (TemplateStore or None): template store instance to
use
Returns:
Tuple(str, dict): Path with the disk and metadata
Raises:
RuntimeError: If the type of the disk is not supported or failed to
create the disk
"""
logging.debug("Creating disk for '%s': %s", name, spec)
disk_metadata = {}
disk_filename = '%s_%s.%s' % (name, spec['name'], spec['format'])
disk_path = self.paths.images(disk_filename)
if spec['type'] == 'template':
if template_store is None or template_repo is None:
raise RuntimeError('No templates directory provided')
template = template_repo.get_by_name(spec['template_name'])
template_version = template.get_version(
spec.get('template_version', None)
)
if template_version not in template_store:
logging.debug(
" Template %s not in cache, downloading",
template_version,
)
template_store.download(template_version)
template_store.mark_used(template_version, self.paths.uuid())
disk_metadata.update(
template_store.get_stored_metadata(
template_version,
),
)
base = template_store.get_path(template_version)
qemu_img_cmd = ['qemu-img', 'create', '-f', 'qcow2',
'-b', base, disk_path]
try:
template_hash = template_store.get_stored_hash(
template_version
)
except:
template_hash = '<unversioned>'
logging.info(
'Creating disk %s:%s from template image %s, versioned as %s',
name,
spec['name'],
spec['template_name'],
template_hash,
)
elif spec['type'] == 'empty':
qemu_img_cmd = ['qemu-img', 'create', '-f', spec['format'],
disk_path, spec['size']]
elif spec['type'] == 'file':
# If we're using raw file, just return it's path
return spec['path'], disk_metadata
else:
raise RuntimeError('Unknown drive spec %s' % str(spec))
if os.path.exists(disk_path):
os.unlink(disk_path)
logging.debug('Running command: %s', ' '.join(qemu_img_cmd))
ret, _, _ = utils.run_command(qemu_img_cmd)
if ret != 0:
raise RuntimeError(
'Failed to create image, qemu-img returned %d' % ret,
)
# To avoid losing access to the file
os.chmod(disk_path, 0666)
logging.info('Successfully created disk at %s', disk_path)
return disk_path, disk_metadata
[docs] def _use_prototype(
self,
spec,
conf
):
"""
Populates the given spec with the values of it's declared prototype
Args:
spec (dict): spec to update
conf (dict): Configuration spec containing the prototypes
Returns:
dict: updated spec
"""
prototype = conf['prototypes'][spec['based-on']]
del spec['based-on']
for attr in prototype:
if attr not in spec:
spec[attr] = copy.deepcopy(prototype[attr])
return spec
[docs] def virt_conf(
self,
conf,
template_repo=None,
template_store=None,
):
"""
Initializes all the virt infrastructure of the prefix, creating the
domains disks, doing any network leases and creating all the virt
related files and dirs inside this prefix.
Args:
conf (dict): Configuration spec
template_repo (TemplateRepository): template repository intance
template_store (TemplateStore): template store instance
Returns:
None
"""
with utils.RollbackContext() as rollback:
if not os.path.exists(self.paths.images()):
os.mkdir(self.paths.images())
rollback.prependDefer(os.unlink, self.paths.images())
if not os.path.exists(self.paths.virt()):
os.mkdir(self.paths.virt())
rollback.prependDefer(os.unlink, self.paths.virt())
for name, spec in conf['domains'].items():
if 'based-on' in spec:
spec = self._use_prototype(spec, conf)
new_disks = []
spec['name'] = name
for disk in spec['disks']:
path, metadata = self._create_disk(
name,
disk,
template_repo,
template_store,
)
new_disks.append(
{
'path': path,
'dev': disk['dev'],
'format': disk['format'],
'metadata': metadata,
},
)
conf['domains'][name]['disks'] = new_disks
self._config_net_topology(conf)
env = virt.VirtEnv(self, conf['domains'], conf['nets'])
env.save()
env.bootstrap()
rollback.clear()
[docs] def start(self):
"""
Start this prefix
Returns:
None
"""
self.virt_env.start()
[docs] def stop(self):
"""
Stop this prefix
Returns:
None
"""
self.virt_env.stop()
[docs] def create_snapshots(self, name):
"""
Creates one snapshot on all the domains with the given name
Args:
name (str): Name of the snapshots to create
Returns:
None
"""
self.virt_env.create_snapshots(name)
[docs] def revert_snapshots(self, name):
"""
Revert all the snapshots with the given name from all the domains
Args:
name (str): Name of the snapshots to revert
Returns:
None
"""
self.virt_env.revert_snapshots(name)
[docs] def _create_virt_env(self):
"""
Create a new virt env from this prefix
Returns:
lago.virt.VirtEnv: virt env created from this prefix
"""
return virt.VirtEnv.from_prefix(self)
@property
def virt_env(self):
"""
Getter for this instance's virt env, creates it if needed
Returns:
lago.virt.VirtEnv: virt env instance used by this prefix
"""
if self._virt_env is None:
self._virt_env = self._create_virt_env()
return self._virt_env
