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OpenStack Study: cisco_nexus_network_driver_v2.py

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# vim: tabstop=4 shiftwidth=4 softtabstop=4

# Licensed under the Apache License, Version 2.0 (the "License"); you may

# not use this file except in compliance with the License. You may obtain

# a copy of the License at

# http://www.apache.org/licenses/LICENSE-2.0

# Unless required by applicable law or agreed to in writing, software

# distributed under the License is distributed on an "AS IS" BASIS, WITHOUT

# WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the

# License for the specific language governing permissions and limitations

# under the License.

# @author: Debojyoti Dutta, Cisco Systems, Inc.

# @author: Edgar Magana, Cisco Systems Inc.

"""

Implements a Nexus-OS NETCONF over SSHv2 API Client

"""

import logging

from ncclient import manager

from neutron.openstack.common import excutils

from neutron.plugins.cisco.common import cisco_constants as const

from neutron.plugins.cisco.common import cisco_credentials_v2 as cred

from neutron.plugins.cisco.common import cisco_exceptions as cexc

from neutron.plugins.cisco.common import config as conf

from neutron.plugins.cisco.db import nexus_db_v2

from neutron.plugins.cisco.nexus import cisco_nexus_snippets as snipp

LOG = logging.getLogger(__name__)

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class CiscoNEXUSDriver():

"""Nexus Driver Main Class."""

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def __init__(self):

cisco_switches = conf.get_device_dictionary()

self.nexus_switches = dict(((key[1], key[2]), val)

for key, val in cisco_switches.items()

if key[0] == 'NEXUS_SWITCH')

self.credentials = {}

self.connections = {}

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def _edit_config(self, nexus_host, target='running', config='',

allowed_exc_strs=None):

"""Modify switch config for a target config type.

:param nexus_host: IP address of switch to configure

:param target: Target config type

:param config: Configuration string in XML format

:param allowed_exc_strs: Exceptions which have any of these strings

as a subset of their exception message

(str(exception)) can be ignored

:raises: NexusConfigFailed

"""

if not allowed_exc_strs:

allowed_exc_strs = []

mgr = self.nxos_connect(nexus_host)

try:

mgr.edit_config(target, config=config)

except Exception as e:

for exc_str in allowed_exc_strs:

if exc_str in str(e):

break

else:

# Raise a Neutron exception. Include a description of

# the original ncclient exception. No need to preserve T/B

raise cexc.NexusConfigFailed(config=config, exc=e)

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def get_credential(self, nexus_ip):

if nexus_ip not in self.credentials:

nexus_username = cred.Store.get_username(nexus_ip)

nexus_password = cred.Store.get_password(nexus_ip)

self.credentials[nexus_ip] = {

const.USERNAME: nexus_username,

const.PASSWORD: nexus_password

}

return self.credentials[nexus_ip]

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def nxos_connect(self, nexus_host):

"""Make SSH connection to the Nexus Switch."""

if getattr(self.connections.get(nexus_host), 'connected', None):

return self.connections[nexus_host]

nexus_ssh_port = int(self.nexus_switches[nexus_host, 'ssh_port'])

nexus_creds = self.get_credential(nexus_host)

nexus_user = nexus_creds[const.USERNAME]

nexus_password = nexus_creds[const.PASSWORD]

try:

man = manager.connect(host=nexus_host,

port=nexus_ssh_port,

username=nexus_user,

password=nexus_password)

self.connections[nexus_host] = man

except Exception as e:

# Raise a Neutron exception. Include a description of

# the original ncclient exception. No need to preserve T/B.

raise cexc.NexusConnectFailed(nexus_host=nexus_host, exc=e)

return self.connections[nexus_host]

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def create_xml_snippet(self, cutomized_config):

"""Create XML snippet.

Creates the Proper XML structure for the Nexus Switch Configuration.

"""

conf_xml_snippet = snipp.EXEC_CONF_SNIPPET % (cutomized_config)

return conf_xml_snippet

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def create_vlan(self, nexus_host, vlanid, vlanname):

"""Create a VLAN on Nexus Switch given the VLAN ID and Name."""

confstr = self.create_xml_snippet(

snipp.CMD_VLAN_CONF_SNIPPET % (vlanid, vlanname))

self._edit_config(nexus_host, target='running', config=confstr)

# Enable VLAN active and no-shutdown states. Some versions of

# Nexus switch do not allow state changes for the extended VLAN

# range (1006-4094), but these errors can be ignored (default

# values are appropriate).

state_config = [snipp.CMD_VLAN_ACTIVE_SNIPPET,

snipp.CMD_VLAN_NO_SHUTDOWN_SNIPPET]

for snippet in state_config:

try:

confstr = self.create_xml_snippet(snippet % vlanid)

allowed_exc_strs=["Can't modify state for extended",

"Command is only allowed on VLAN"])

except cexc.NexusConfigFailed:

with excutils.save_and_reraise_exception():

self.delete_vlan(nexus_host, vlanid)

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def delete_vlan(self, nexus_host, vlanid):

"""Delete a VLAN on Nexus Switch given the VLAN ID."""

confstr = snipp.CMD_NO_VLAN_CONF_SNIPPET % vlanid

confstr = self.create_xml_snippet(confstr)

self._edit_config(nexus_host, target='running', config=confstr)

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def enable_vlan_on_trunk_int(self, nexus_host, vlanid, etype, interface):

"""Enable a VLAN on a trunk interface."""

# If one or more VLANs are already configured on this interface,

# include the 'add' keyword.

if nexus_db_v2.get_port_switch_bindings('%s:%s' % (etype, interface),

nexus_host):

snippet = snipp.CMD_INT_VLAN_ADD_SNIPPET

else:

snippet = snipp.CMD_INT_VLAN_SNIPPET

confstr = snippet % (etype, interface, vlanid, etype)

confstr = self.create_xml_snippet(confstr)

LOG.debug(_("NexusDriver: %s"), confstr)

self._edit_config(nexus_host, target='running', config=confstr)

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def disable_vlan_on_trunk_int(self, nexus_host, vlanid, etype, interface):

"""Disable a VLAN on a trunk interface."""

confstr = snipp.CMD_NO_VLAN_INT_SNIPPET % (etype, interface,

vlanid, etype)

confstr = self.create_xml_snippet(confstr)

LOG.debug(_("NexusDriver: %s"), confstr)

self._edit_config(nexus_host, target='running', config=confstr)

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def create_and_trunk_vlan(self, nexus_host, vlan_id, vlan_name,

etype, nexus_port):

"""Create VLAN and trunk it on the specified ports."""

self.create_vlan(nexus_host, vlan_id, vlan_name)

LOG.debug(_("NexusDriver created VLAN: %s"), vlan_id)

if nexus_port:

self.enable_vlan_on_trunk_int(nexus_host, vlan_id,

etype, nexus_port)

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def delete_and_untrunk_vlan(self, nexus_host, vlan_id, etype, nexus_port):

"""Delete VLAN and untrunk it from the specified ports."""

self.delete_vlan(nexus_host, vlan_id)

if nexus_port:

self.disable_vlan_on_trunk_int(nexus_host, vlan_id,

etype, nexus_port)

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def create_vlan_svi(self, nexus_host, vlan_id, gateway_ip):

confstr = snipp.CMD_VLAN_SVI_SNIPPET % (vlan_id, gateway_ip)

confstr = self.create_xml_snippet(confstr)

LOG.debug(_("NexusDriver: %s"), confstr)

self._edit_config(nexus_host, target='running', config=confstr)

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def delete_vlan_svi(self, nexus_host, vlan_id):

confstr = snipp.CMD_NO_VLAN_SVI_SNIPPET % vlan_id

confstr = self.create_xml_snippet(confstr)

LOG.debug(_("NexusDriver: %s"), confstr)

self._edit_config(nexus_host, target='running', config=confstr)