extras/vpp_config/vpplib/AutoConfig.py

# Copyright (c) 2016 Cisco and/or its affiliates.
# 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.

"""Library that supports Auto Configuration."""

import logging
import os
import re
import yaml
from netaddr import IPAddress

from vpplib.VPPUtil import VPPUtil
from vpplib.VppPCIUtil import VppPCIUtil
from vpplib.VppHugePageUtil import VppHugePageUtil
from vpplib.CpuUtils import CpuUtils
from vpplib.VppGrubUtil import VppGrubUtil
from vpplib.QemuUtils import QemuUtils

__all__ = ["AutoConfig"]

# Constants
MIN_SYSTEM_CPUS = 2
MIN_TOTAL_HUGE_PAGES = 1024
MAX_PERCENT_FOR_HUGE_PAGES = 70


class AutoConfig(object):
    """Auto Configuration Tools"""

    def __init__(self, rootdir, filename, clean=False):
        """
        The Auto Configure class.

        :param rootdir: The root directory for all the auto configuration files
        :param filename: The autoconfiguration file
        :param clean: When set initialize the nodes from the auto-config file
        :type rootdir: str
        :type filename: str
        :type clean: bool
        """
        self._autoconfig_filename = rootdir + filename
        self._rootdir = rootdir
        self._metadata = {}
        self._nodes = {}
        self._vpp_devices_node = {}
        self._hugepage_config = ""
        self._clean = clean
        self._loadconfig()

    def get_nodes(self):
        """
        Returns the nodes dictionary.

        :returns: The nodes
        :rtype: dictionary
        """

        return self._nodes

    @staticmethod
    def _autoconfig_backup_file(filename):
        """
        Create a backup file.

        :param filename: The file to backup
        :type filename: str
        """

        # Does a copy of the file exist, if not create one
        ofile = filename + '.orig'
        (ret, stdout, stderr) = VPPUtil.exec_command('ls {}'.format(ofile))
        if ret != 0:
            logging.debug(stderr)
            if stdout.strip('\n') != ofile:
                cmd = 'sudo cp {} {}'.format(filename, ofile)
                (ret, stdout, stderr) = VPPUtil.exec_command(cmd)
                if ret != 0:
                    logging.debug(stderr)

    # noinspection PyBroadException
    @staticmethod
    def _ask_user_ipv4():
        """
        Asks the user for a number within a range.
        default is returned if return is entered.

        :returns: IP address with cidr
        :rtype: str
        """

        while True:
            answer = raw_input("Please enter the IPv4 Address [n.n.n.n/n]: ")
            try:
                ipinput = answer.split('/')
                ipaddr = IPAddress(ipinput[0])
                if len(ipinput) > 1:
                    plen = answer.split('/')[1]
                else:
                    answer = raw_input("Please enter the netmask [n.n.n.n]: ")
                    plen = IPAddress(answer).netmask_bits()
                return '{}/{}'.format(ipaddr, plen)
            except:
                print "Please enter a valid IPv4 address."
                continue

    @staticmethod
    def _ask_user_range(question, first, last, default):
        """
        Asks the user for a number within a range.
        default is returned if return is entered.

        :param question: Text of a question.
        :param first: First number in the range
        :param last: Last number in the range
        :param default: The value returned when return is entered
        :type question: string
        :type first: int
        :type last: int
        :type default: int
        :returns: The answer to the question
        :rtype: int
        """

        while True:
            answer = raw_input(question)
            if answer == '':
                answer = default
                break
            if re.findall(r'[0-9+]', answer):
                if int(answer) in range(first, last + 1):
                    break
                else:
                    print "Please a value between {} and {} or Return.". \
                        format(first, last)
            else:
                print "Please a number between {} and {} or Return.". \
                    format(first, last)

        return int(answer)

    @staticmethod
    def _ask_user_yn(question, default):
        """
        Asks the user for a yes or no question.

        :param question: Text of a question.
        :param default: The value returned when return is entered
        :type question: string
        :type default: string
        :returns: The answer to the question
        :rtype: string
        """

        input_valid = False
        default = default.lower()
        answer = ''
        while not input_valid:
            answer = raw_input(question)
            if answer == '':
                answer = default
            if re.findall(r'[YyNn]', answer):
                input_valid = True
                answer = answer[0].lower()
            else:
                print "Please answer Y, N or Return."

        return answer

    def _loadconfig(self):
        """
        Load the testbed configuration, given the auto configuration file.

        """

        # Get the Topology, from the topology layout file
        topo = {}
        with open(self._autoconfig_filename, 'r') as stream:
            try:
                topo = yaml.load(stream)
                if 'metadata' in topo:
                    self._metadata = topo['metadata']
            except yaml.YAMLError as exc:
                raise RuntimeError("Couldn't read the Auto config file {}.".format(self._autoconfig_filename, exc))

        systemfile = self._rootdir + self._metadata['system_config_file']
        if self._clean is False and os.path.isfile(systemfile):
            with open(systemfile, 'r') as sysstream:
                try:
                    systopo = yaml.load(sysstream)
                    if 'nodes' in systopo:
                        self._nodes = systopo['nodes']
                except yaml.YAMLError as sysexc:
                    raise RuntimeError("Couldn't read the System config file {}.".format(systemfile, sysexc))
        else:
            # Get the nodes from Auto Config
            if 'nodes' in topo:
                self._nodes = topo['nodes']

        # Set the root directory in all the nodes
        for i in self._nodes.items():
            node = i[1]
            node['rootdir'] = self._rootdir

    def updateconfig(self):
        """
        Update the testbed configuration, given the auto configuration file.
        We will write the system configuration file with the current node
        information

        """

        # Initialize the yaml data
        ydata = {'metadata': self._metadata, 'nodes': self._nodes}

        # Write the system config file
        filename = self._rootdir + self._metadata['system_config_file']
        with open(filename, 'w') as yamlfile:
            yaml.dump(ydata, yamlfile)

    def _update_auto_config(self):
        """
        Write the auto configuration file with the new configuration data,
        input from the user.

        """

        # Initialize the yaml data
        nodes = {}
        with open(self._autoconfig_filename, 'r') as stream:
            try:
                ydata = yaml.load(stream)
                if 'nodes' in ydata:
                    nodes = ydata['nodes']
            except yaml.YAMLError as exc:
                print exc
                return

        for i in nodes.items():
            key = i[0]
            node = i[1]

            # Interfaces
            node['interfaces'] = {}
            for item in self._nodes[key]['interfaces'].items():
                port = item[0]
                interface = item[1]

                node['interfaces'][port] = {}
                addr = '{}'.format(interface['pci_address'])
                node['interfaces'][port]['pci_address'] = addr
                if 'mac_address' in interface:
                    node['interfaces'][port]['mac_address'] = \
                        interface['mac_address']

            if 'total_other_cpus' in self._nodes[key]['cpu']:
                node['cpu']['total_other_cpus'] = \
                    self._nodes[key]['cpu']['total_other_cpus']
            if 'total_vpp_cpus' in self._nodes[key]['cpu']:
                node['cpu']['total_vpp_cpus'] = \
                    self._nodes[key]['cpu']['total_vpp_cpus']
            if 'reserve_vpp_main_core' in self._nodes[key]['cpu']:
                node['cpu']['reserve_vpp_main_core'] = \
                    self._nodes[key]['cpu']['reserve_vpp_main_core']

            # TCP
            if 'active_open_sessions' in self._nodes[key]['tcp']:
                node['tcp']['active_open_sessions'] = \
                    self._nodes[key]['tcp']['active_open_sessions']
            if 'passive_open_sessions' in self._nodes[key]['tcp']:
                node['tcp']['passive_open_sessions'] = \
                    self._nodes[key]['tcp']['passive_open_sessions']

            # Huge pages
            node['hugepages']['total'] = self._nodes[key]['hugepages']['total']

        # Write the auto config config file
        with open(self._autoconfig_filename, 'w') as yamlfile:
            yaml.dump(ydata, yamlfile)

    def apply_huge_pages(self):
        """
        Apply the huge page config

        """

        for i in self._nodes.items():
            node = i[1]

            hpg = VppHugePageUtil(node)
            hpg.hugepages_dryrun_apply()

    @staticmethod
    def _apply_vpp_unix(node):
        """
        Apply the VPP Unix config

        :param node: Node dictionary with cpuinfo.
        :type node: dict
        """

        unix = '  nodaemon\n'
        if 'unix' not in node['vpp']:
            return ''

        unixv = node['vpp']['unix']
        if 'interactive' in unixv:
            interactive = unixv['interactive']
            if interactive is True:
                unix = '  interactive\n'

        return unix.rstrip('\n')

    @staticmethod
    def _apply_vpp_cpu(node):
        """
        Apply the VPP cpu config

        :param node: Node dictionary with cpuinfo.
        :type node: dict
        """

        # Get main core
        cpu = '\n'
        if 'vpp_main_core' in node['cpu']:
            vpp_main_core = node['cpu']['vpp_main_core']
        else:
            vpp_main_core = 0
        if vpp_main_core is not 0:
            cpu += '  main-core {}\n'.format(vpp_main_core)

        # Get workers
        vpp_workers = node['cpu']['vpp_workers']
        vpp_worker_len = len(vpp_workers)
        if vpp_worker_len > 0:
            vpp_worker_str = ''
            for i, worker in enumerate(vpp_workers):
                if i > 0:
                    vpp_worker_str += ','
                if worker[0] == worker[1]:
                    vpp_worker_str += "{}".format(worker[0])
                else:
                    vpp_worker_str += "{}-{}".format(worker[0], worker[1])

            cpu += '  corelist-workers {}\n'.format(vpp_worker_str)

        return cpu

    @staticmethod
    def _apply_vpp_devices(node):
        """
        Apply VPP PCI Device configuration to vpp startup.

        :param node: Node dictionary with cpuinfo.
        :type node: dict
        """

        devices = ''
        ports_per_numa = node['cpu']['ports_per_numa']
        total_mbufs = node['cpu']['total_mbufs']

        for item in ports_per_numa.items():
            value = item[1]
            interfaces = value['interfaces']

            # if 0 was specified for the number of vpp workers, use 1 queue
            num_rx_queues = None
            num_tx_queues = None
            if 'rx_queues' in value:
                num_rx_queues = value['rx_queues']
            if 'tx_queues' in value:
                num_tx_queues = value['tx_queues']

            num_rx_desc = None
            num_tx_desc = None

            # Create the devices string
            for interface in interfaces:
                pci_address = interface['pci_address']
                pci_address = pci_address.lstrip("'").rstrip("'")
                devices += '\n'
                devices += '  dev {} {{ \n'.format(pci_address)
                if num_rx_queues:
                    devices += '    num-rx-queues {}\n'.format(num_rx_queues)
                else:
                    devices += '    num-rx-queues {}\n'.format(1)
                if num_tx_queues:
                    devices += '    num-tx-queues {}\n'.format(num_tx_queues)
                if num_rx_desc:
                    devices += '    num-rx-desc {}\n'.format(num_rx_desc)
                if num_tx_desc:
                    devices += '    num-tx-desc {}\n'.format(num_tx_desc)
                devices += '  }'

        if total_mbufs is not 0:
            devices += '\n  num-mbufs {}'.format(total_mbufs)

        return devices

    @staticmethod
    def _calc_vpp_workers(node, vpp_workers, numa_node,
                          other_cpus_end, total_vpp_workers,
                          reserve_vpp_main_core):
        """
        Calculate the VPP worker information

        :param node: Node dictionary
        :param vpp_workers: List of VPP workers
        :param numa_node: Numa node
        :param other_cpus_end: The end of the cpus allocated for cores
        other than vpp
        :param total_vpp_workers: The number of vpp workers needed
        :param reserve_vpp_main_core: Is there a core needed for
        the vpp main core
        :type node: dict
        :type numa_node: int
        :type other_cpus_end: int
        :type total_vpp_workers: int
        :type reserve_vpp_main_core: bool
        :returns: Is a core still needed for the vpp main core
        :rtype: bool
        """

        # Can we fit the workers in one of these slices
        cpus = node['cpu']['cpus_per_node'][numa_node]
        for cpu in cpus:
            start = cpu[0]
            end = cpu[1]
            if start <= other_cpus_end:
                start = other_cpus_end + 1

            if reserve_vpp_main_core:
                start += 1

            workers_end = start + total_vpp_workers - 1
            if workers_end <= end:
                if reserve_vpp_main_core:
                    node['cpu']['vpp_main_core'] = start - 1
                reserve_vpp_main_core = False
                if total_vpp_workers:
                    vpp_workers.append((start, workers_end))
                break

        # We still need to reserve the main core
        if reserve_vpp_main_core:
            node['cpu']['vpp_main_core'] = other_cpus_end + 1

        return reserve_vpp_main_core

    @staticmethod
    def _calc_desc_and_queues(total_numa_nodes,
                              total_ports_per_numa,
                              total_vpp_cpus,
                              ports_per_numa_value):
        """
        Calculate the number of descriptors and queues

        :param total_numa_nodes: The total number of numa nodes
        :param total_ports_per_numa: The total number of ports for this
        numa node
        :param total_vpp_cpus: The total number of cpus to allocate for vpp
        :param ports_per_numa_value: The value from the ports_per_numa
        dictionary
        :type total_numa_nodes: int
        :type total_ports_per_numa: int
        :type total_vpp_cpus: int
        :type ports_per_numa_value: dict
        :returns The total number of message buffers
        :returns: The total number of vpp workers
        :rtype: int
        :rtype: int
        """

        # Get the total vpp workers
        total_vpp_workers = total_vpp_cpus
        ports_per_numa_value['total_vpp_workers'] = total_vpp_workers

        # Get the number of rx queues
        rx_queues = max(1, total_vpp_workers)
        tx_queues = total_vpp_workers * total_numa_nodes + 1

        # Get the descriptor entries
        desc_entries = 1024
        ports_per_numa_value['rx_queues'] = rx_queues
        total_mbufs = (((rx_queues * desc_entries) +
                        (tx_queues * desc_entries)) *
                       total_ports_per_numa)
        total_mbufs = total_mbufs

        return total_mbufs, total_vpp_workers

    @staticmethod
    def _create_ports_per_numa(node, interfaces):
        """
        Create a dictionary or ports per numa node
        :param node: Node dictionary
        :param interfaces: All the interfaces to be used by vpp
        :type node: dict
        :type interfaces: dict
        :returns: The ports per numa dictionary
        :rtype: dict
        """

        # Make a list of ports by numa node
        ports_per_numa = {}
        for item in interfaces.items():
            i = item[1]
            if i['numa_node'] not in ports_per_numa:
                ports_per_numa[i['numa_node']] = {'interfaces': []}
                ports_per_numa[i['numa_node']]['interfaces'].append(i)
            else:
                ports_per_numa[i['numa_node']]['interfaces'].append(i)
        node['cpu']['ports_per_numa'] = ports_per_numa

        return ports_per_numa

    def calculate_cpu_parameters(self):
        """
        Calculate the cpu configuration.

        """

        # Calculate the cpu parameters, needed for the
        # vpp_startup and grub configuration
        for i in self._nodes.items():
            node = i[1]

            # get total number of nic ports
            interfaces = node['interfaces']

            # Make a list of ports by numa node
            ports_per_numa = self._create_ports_per_numa(node, interfaces)

            # Get the number of cpus to skip, we never use the first cpu
            other_cpus_start = 1
            other_cpus_end = other_cpus_start + \
                node['cpu']['total_other_cpus'] - 1
            other_workers = None
            if other_cpus_end is not 0:
                other_workers = (other_cpus_start, other_cpus_end)
            node['cpu']['other_workers'] = other_workers

            # Allocate the VPP main core and workers
            vpp_workers = []
            reserve_vpp_main_core = node['cpu']['reserve_vpp_main_core']
            total_vpp_cpus = node['cpu']['total_vpp_cpus']

            # If total_vpp_cpus is 0 or is less than the numa nodes with ports
            #  then we shouldn't get workers
            total_with_main = total_vpp_cpus
            if reserve_vpp_main_core:
                total_with_main += 1
            total_mbufs = 0
            if total_with_main is not 0:
                for item in ports_per_numa.items():
                    numa_node = item[0]
                    value = item[1]

                    # Get the number of descriptors and queues
                    mbufs, total_vpp_workers = self._calc_desc_and_queues(
                        len(ports_per_numa),
                        len(value['interfaces']), total_vpp_cpus, value)
                    total_mbufs += mbufs

                    # Get the VPP workers
                    reserve_vpp_main_core = self._calc_vpp_workers(
                        node, vpp_workers, numa_node, other_cpus_end,
                        total_vpp_workers, reserve_vpp_main_core)

                total_mbufs *= 2.5
                total_mbufs = int(total_mbufs)
            else:
                total_mbufs = 0

            # Save the info
            node['cpu']['vpp_workers'] = vpp_workers
            node['cpu']['total_mbufs'] = total_mbufs

        # Write the config
        self.updateconfig()

    @staticmethod
    def _apply_vpp_tcp(node):
        """
        Apply the VPP Unix config

        :param node: Node dictionary with cpuinfo.
        :type node: dict
        """

        active_open_sessions = node['tcp']['active_open_sessions']
        aos = int(active_open_sessions)

        passive_open_sessions = node['tcp']['passive_open_sessions']
        pos = int(passive_open_sessions)

        # Generate the api-segment gid vpp sheit in any case
        if (aos + pos) == 0:
            tcp = "api-segment {\n"
            tcp = tcp + "  gid vpp\n"
            tcp = tcp + "}\n"
            return tcp.rstrip('\n')

        tcp = "# TCP stack-related configuration parameters\n"
        tcp = tcp + "# expecting {:d} client sessions, {:d} server sessions\n\n".format(aos, pos)
        tcp = tcp + "heapsize 4g\n\n"
        tcp = tcp + "api-segment {\n"
        tcp = tcp + "  global-size 2000M\n"
        tcp = tcp + "  api-size 1G\n"
        tcp = tcp + "}\n\n"

        tcp = tcp + "session {\n"
        tcp = tcp + "  event-queue-length " + "{:d}".format(aos + pos) + "\n"
        tcp = tcp + "  preallocated-sessions " + "{:d}".format(aos + pos) + "\n"
        tcp = tcp + "  v4-session-table-buckets " + "{:d}".format((aos + pos) / 4) + "\n"
        tcp = tcp + "  v4-session-table-memory 3g\n"
        if aos > 0:
            tcp = tcp + "  v4-halfopen-table-buckets " + \
                  "{:d}".format((aos + pos) / 4) + "\n"
            tcp = tcp + "  v4-halfopen-table-memory 3g\n"
        tcp = tcp + "}\n\n"

        tcp = tcp + "tcp {\n"
        tcp = tcp + "  preallocated-connections " + "{:d}".format(aos + pos) + "\n"
        if aos > 0:
            tcp = tcp + "  preallocated-half-open-connections " + "{:d}".format(aos) + "\n"
            tcp = tcp + "  local-endpoints-table-buckets " + "{:d}".format((aos + pos) / 4) + "\n"
            tcp = tcp + "  local-endpoints-table-memory 3g\n"
        tcp = tcp + "}\n\n"

        return tcp.rstrip('\n')

    def apply_vpp_startup(self):
        """
        Apply the vpp startup configration

        """

        # Apply the VPP startup configruation
        for i in self._nodes.items():
            node = i[1]

            # Get the startup file
            rootdir = node['rootdir']
            sfile = rootdir + node['vpp']['startup_config_file']

            # Get the devices
            devices = self._apply_vpp_devices(node)

            # Get the CPU config
            cpu = self._apply_vpp_cpu(node)

            # Get the unix config
            unix = self._apply_vpp_unix(node)

            # Get the TCP configuration, if any
            tcp = self._apply_vpp_tcp(node)

            # Make a backup if needed
            self._autoconfig_backup_file(sfile)

            # Get the template
            tfile = sfile + '.template'
            (ret, stdout, stderr) = \
                VPPUtil.exec_command('cat {}'.format(tfile))
            if ret != 0:
                raise RuntimeError('Executing cat command failed to node {}'.
                                   format(node['host']))
            startup = stdout.format(unix=unix,
                                    cpu=cpu,
                                    devices=devices,
                                    tcp=tcp)

            (ret, stdout, stderr) = \
                VPPUtil.exec_command('rm {}'.format(sfile))
            if ret != 0:
                logging.debug(stderr)

            cmd = "sudo cat > {0} << EOF\n{1}\n".format(sfile, startup)
            (ret, stdout, stderr) = VPPUtil.exec_command(cmd)
            if ret != 0:
                raise RuntimeError('Writing config failed node {}'.
                                   format(node['host']))

    def apply_grub_cmdline(self):
        """
        Apply the grub cmdline

        """

        for i in self._nodes.items():
            node = i[1]

            # Get the isolated CPUs
            other_workers = node['cpu']['other_workers']
            vpp_workers = node['cpu']['vpp_workers']
            if 'vpp_main_core' in node['cpu']:
                vpp_main_core = node['cpu']['vpp_main_core']
            else:
                vpp_main_core = 0
            all_workers = []
            if other_workers is not None:
                all_workers = [other_workers]
            if vpp_main_core is not 0:
                all_workers += [(vpp_main_core, vpp_main_core)]
            all_workers += vpp_workers
            isolated_cpus = ''
            for idx, worker in enumerate(all_workers):
                if worker is None:
                    continue
                if idx > 0:
                    isolated_cpus += ','
                if worker[0] == worker[1]:
                    isolated_cpus += "{}".format(worker[0])
                else:
                    isolated_cpus += "{}-{}".format(worker[0], worker[1])

            vppgrb = VppGrubUtil(node)
            current_cmdline = vppgrb.get_current_cmdline()
            if 'grub' not in node:
                node['grub'] = {}
            node['grub']['current_cmdline'] = current_cmdline
            node['grub']['default_cmdline'] = \
                vppgrb.apply_cmdline(node, isolated_cpus)

        self.updateconfig()

    def get_hugepages(self):
        """
        Get the hugepage configuration

        """

        for i in self._nodes.items():
            node = i[1]

            hpg = VppHugePageUtil(node)
            max_map_count, shmmax = hpg.get_huge_page_config()
            node['hugepages']['max_map_count'] = max_map_count
            node['hugepages']['shmax'] = shmmax
            total, free, size, memtotal, memfree = hpg.get_actual_huge_pages()
            node['hugepages']['actual_total'] = total
            node['hugepages']['free'] = free
            node['hugepages']['size'] = size
            node['hugepages']['memtotal'] = memtotal
            node['hugepages']['memfree'] = memfree

        self.updateconfig()

    def get_grub(self):
        """
        Get the grub configuration

        """

        for i in self._nodes.items():
            node = i[1]

            vppgrb = VppGrubUtil(node)
            current_cmdline = vppgrb.get_current_cmdline()
            default_cmdline = vppgrb.get_default_cmdline()

            # Get the total number of isolated CPUs
            current_iso_cpus = 0
            iso_cpur = re.findall(r'isolcpus=[\w+\-,]+', current_cmdline)
            iso_cpurl = len(iso_cpur)
            if iso_cpurl > 0:
                iso_cpu_str = iso_cpur[0]
                iso_cpu_str = iso_cpu_str.split('=')[1]
                iso_cpul = iso_cpu_str.split(',')
                for iso_cpu in iso_cpul:
                    isocpuspl = iso_cpu.split('-')
                    if len(isocpuspl) is 1:
                        current_iso_cpus += 1
                    else:
                        first = int(isocpuspl[0])
                        second = int(isocpuspl[1])
                        if first == second:
                            current_iso_cpus += 1
                        else:
                            current_iso_cpus += second - first

            if 'grub' not in node:
                node['grub'] = {}
            node['grub']['current_cmdline'] = current_cmdline
            node['grub']['default_cmdline'] = default_cmdline
            node['grub']['current_iso_cpus'] = current_iso_cpus

        self.updateconfig()

    @staticmethod
    def _get_device(node):
        """
        Get the device configuration for a single node

        :param node: Node dictionary with cpuinfo.
        :type node: dict

        """

        vpp = VppPCIUtil(node)
        vpp.get_all_devices()

        # Save the device information
        node['devices'] = {}
        node['devices']['dpdk_devices'] = vpp.get_dpdk_devices()
        node['devices']['kernel_devices'] = vpp.get_kernel_devices()
        node['devices']['other_devices'] = vpp.get_other_devices()
        node['devices']['linkup_devices'] = vpp.get_link_up_devices()

    def get_devices_per_node(self):
        """
        Get the device configuration for all the nodes

        """

        for i in self._nodes.items():
            node = i[1]
            # Update the interface data

            self._get_device(node)

        self.updateconfig()

    @staticmethod
    def get_cpu_layout(node):
        """
        Get the cpu layout

        using lscpu -p get the cpu layout.
        Returns a list with each item representing a single cpu.

        :param node: Node dictionary.
        :type node: dict
        :returns: The cpu layout
        :rtype: list
        """

        cmd = 'lscpu -p'
        (ret, stdout, stderr) = VPPUtil.exec_command(cmd)
        if ret != 0:
            raise RuntimeError('{} failed on node {} {}'.
                               format(cmd, node['host'], stderr))

        pcpus = []
        lines = stdout.split('\n')
        for line in lines:
            if line == '' or line[0] == '#':
                continue
            linesplit = line.split(',')
            layout = {'cpu': linesplit[0], 'core': linesplit[1],
                      'socket': linesplit[2], 'node': linesplit[3]}

            # cpu, core, socket, node
            pcpus.append(layout)

        return pcpus

    def get_cpu(self):
        """
        Get the cpu configuration

        """

        # Get the CPU layout
        CpuUtils.get_cpu_layout_from_all_nodes(self._nodes)

        for i in self._nodes.items():
            node = i[1]

            # Get the cpu layout
            layout = self.get_cpu_layout(node)
            node['cpu']['layout'] = layout

            cpuinfo = node['cpuinfo']
            smt_enabled = CpuUtils.is_smt_enabled(cpuinfo)
            node['cpu']['smt_enabled'] = smt_enabled

            # We don't want to write the cpuinfo
            node['cpuinfo'] = ""

        # Write the config
        self.updateconfig()

    def discover(self):
        """
        Get the current system configuration.

        """

        # Get the Huge Page configuration
        self.get_hugepages()

        # Get the device configuration
        self.get_devices_per_node()

        # Get the CPU configuration
        self.get_cpu()

        # Get the current grub cmdline
        self.get_grub()

    def _modify_cpu_questions(self, node, total_cpus, numa_nodes):
        """
        Ask the user questions related to the cpu configuration.

        :param node: Node dictionary
        :param total_cpus: The total number of cpus in the system
        :param numa_nodes: The list of numa nodes in the system
        :type node: dict
        :type total_cpus: int
        :type numa_nodes: list
        """

        print "\nYour system has {} core(s) and {} Numa Nodes.". \
            format(total_cpus, len(numa_nodes))
        print "To begin, we suggest not reserving any cores for VPP",
        print "or other processes."
        print "Then to improve performance try reserving cores as needed. "

        max_other_cores = total_cpus / 2
        question = '\nHow many core(s) do you want to reserve for processes \
other than VPP? [0-{}][0]? '.format(str(max_other_cores))
        total_other_cpus = self._ask_user_range(question, 0, max_other_cores,
                                                0)
        node['cpu']['total_other_cpus'] = total_other_cpus

        max_vpp_cpus = 4
        total_vpp_cpus = 0
        if max_vpp_cpus > 0:
            question = "How many core(s) shall we reserve for VPP workers[0-{}][0]? ". \
                format(max_vpp_cpus)
            total_vpp_cpus = self._ask_user_range(question, 0, max_vpp_cpus, 0)
            node['cpu']['total_vpp_cpus'] = total_vpp_cpus

        max_main_cpus = max_vpp_cpus - total_vpp_cpus
        reserve_vpp_main_core = False
        if max_main_cpus > 0:
            question = "Should we reserve 1 core for the VPP Main thread? "
            question += "[y/N]? "
            answer = self._ask_user_yn(question, 'n')
            if answer == 'y':
                reserve_vpp_main_core = True
            node['cpu']['reserve_vpp_main_core'] = reserve_vpp_main_core
            node['cpu']['vpp_main_core'] = 0

    def modify_cpu(self, ask_questions=True):
        """
        Modify the cpu configuration, asking for the user for the values.

        :param ask_questions: When true ask the user for config parameters

        """

        # Get the CPU layout
        CpuUtils.get_cpu_layout_from_all_nodes(self._nodes)

        for i in self._nodes.items():
            node = i[1]
            total_cpus = 0
            total_cpus_per_slice = 0
            cpus_per_node = {}
            numa_nodes = []
            cores = []
            cpu_layout = self.get_cpu_layout(node)

            # Assume the number of cpus per slice is always the same as the
            # first slice
            first_node = '0'
            for cpu in cpu_layout:
                if cpu['node'] != first_node:
                    break
                total_cpus_per_slice += 1

            # Get the total number of cpus, cores, and numa nodes from the
            # cpu layout
            for cpul in cpu_layout:
                numa_node = cpul['node']
                core = cpul['core']
                cpu = cpul['cpu']
                total_cpus += 1

                if numa_node not in cpus_per_node:
                    cpus_per_node[numa_node] = []
                cpuperslice = int(cpu) % total_cpus_per_slice
                if cpuperslice == 0:
                    cpus_per_node[numa_node].append((int(cpu), int(cpu) +
                                                     total_cpus_per_slice - 1))
                if numa_node not in numa_nodes:
                    numa_nodes.append(numa_node)
                if core not in cores:
                    cores.append(core)
            node['cpu']['cpus_per_node'] = cpus_per_node

            # Ask the user some questions
            if ask_questions:
                self._modify_cpu_questions(node, total_cpus, numa_nodes)

            # Populate the interfaces with the numa node
            if 'interfaces' in node:
                ikeys = node['interfaces'].keys()
                VPPUtil.get_interfaces_numa_node(node, *tuple(ikeys))

            # We don't want to write the cpuinfo
            node['cpuinfo'] = ""

        # Write the configs
        self._update_auto_config()
        self.updateconfig()

    def _modify_other_devices(self, node,
                              other_devices, kernel_devices, dpdk_devices):
        """
        Modify the devices configuration, asking for the user for the values.

        """

        odevices_len = len(other_devices)
        if odevices_len > 0:
            print "\nThese device(s) are currently NOT being used",
            print "by VPP or the OS.\n"
            VppPCIUtil.show_vpp_devices(other_devices, show_interfaces=False)
            question = "\nWould you like to give any of these devices"
            question += " back to the OS [Y/n]? "
            answer = self._ask_user_yn(question, 'Y')
            if answer == 'y':
                vppd = {}
                for dit in other_devices.items():
                    dvid = dit[0]
                    device = dit[1]
                    question = "Would you like to use device {} for". \
                        format(dvid)
                    question += " the OS [y/N]? "
                    answer = self._ask_user_yn(question, 'n')
                    if answer == 'y':
                        driver = device['unused'][0]
                        VppPCIUtil.bind_vpp_device(node, driver, dvid)
                        vppd[dvid] = device
                for dit in vppd.items():
                    dvid = dit[0]
                    device = dit[1]
                    kernel_devices[dvid] = device
                    del other_devices[dvid]

        odevices_len = len(other_devices)
        if odevices_len > 0:
            print "\nThese device(s) are still NOT being used ",
            print "by VPP or the OS.\n"
            VppPCIUtil.show_vpp_devices(other_devices, show_interfaces=False)
            question = "\nWould you like use any of these for VPP [y/N]? "
            answer = self._ask_user_yn(question, 'N')
            if answer == 'y':
                vppd = {}
                for dit in other_devices.items():
                    dvid = dit[0]
                    device = dit[1]
                    question = "Would you like to use device {} ".format(dvid)
                    question += "for VPP [y/N]? "
                    answer = self._ask_user_yn(question, 'n')
                    if answer == 'y':
                        vppd[dvid] = device
                for dit in vppd.items():
                    dvid = dit[0]
                    device = dit[1]
                    dpdk_devices[dvid] = device
                    del other_devices[dvid]

    def update_interfaces_config(self):
        """
        Modify the interfaces directly from the config file.

        """

        for i in self._nodes.items():
            node = i[1]
            devices = node['devices']
            all_devices = devices['other_devices']
            all_devices.update(devices['dpdk_devices'])
            all_devices.update(devices['kernel_devices'])

            current_ifcs = {}
            interfaces = {}
            if 'interfaces' in node:
                current_ifcs = node['interfaces']
            if current_ifcs:
                for ifc in current_ifcs.values():
                    dvid = ifc['pci_address']
                    if dvid in all_devices:
                        VppPCIUtil.vpp_create_interface(interfaces, dvid,
                                                        all_devices[dvid])
            node['interfaces'] = interfaces

        self.updateconfig()

    def modify_devices(self):
        """
        Modify the devices configuration, asking for the user for the values.

        """

        for i in self._nodes.items():
            node = i[1]
            devices = node['devices']
            other_devices = devices['other_devices']
            kernel_devices = devices['kernel_devices']
            dpdk_devices = devices['dpdk_devices']

            if other_devices:
                self._modify_other_devices(node, other_devices,
                                           kernel_devices, dpdk_devices)

                # Get the devices again for this node
                self._get_device(node)
                devices = node['devices']
                kernel_devices = devices['kernel_devices']
                dpdk_devices = devices['dpdk_devices']

            klen = len(kernel_devices)
            if klen > 0:
                print "\nThese devices have kernel interfaces, but",
                print "appear to be safe to use with VPP.\n"
                VppPCIUtil.show_vpp_devices(kernel_devices)
                question = "\nWould you like to use any of these "
                question += "device(s) for VPP [y/N]? "
                answer = self._ask_user_yn(question, 'n')
                if answer == 'y':
                    vppd = {}
                    for dit in kernel_devices.items():
                        dvid = dit[0]
                        device = dit[1]
                        question = "Would you like to use device {} ". \
                            format(dvid)
                        question += "for VPP [y/N]? "
                        answer = self._ask_user_yn(question, 'n')
                        if answer == 'y':
                            vppd[dvid] = device
                    for dit in vppd.items():
                        dvid = dit[0]
                        device = dit[1]
                        dpdk_devices[dvid] = device
                        del kernel_devices[dvid]

            dlen = len(dpdk_devices)
            if dlen > 0:
                print "\nThese device(s) will be used by VPP.\n"
                VppPCIUtil.show_vpp_devices(dpdk_devices, show_interfaces=False)
                question = "\nWould you like to remove any of "
                question += "these device(s) [y/N]? "
                answer = self._ask_user_yn(question, 'n')
                if answer == 'y':
                    vppd = {}
                    for dit in dpdk_devices.items():
                        dvid = dit[0]
                        device = dit[1]
                        question = "Would you like to remove {} [y/N]? ". \
                            format(dvid)
                        answer = self._ask_user_yn(question, 'n')
                        if answer == 'y':
                            vppd[dvid] = device
                    for dit in vppd.items():
                        dvid = dit[0]
                        device = dit[1]
                        driver = device['unused'][0]
                        VppPCIUtil.bind_vpp_device(node, driver, dvid)
                        kernel_devices[dvid] = device
                        del dpdk_devices[dvid]

            interfaces = {}
            for dit in dpdk_devices.items():
                dvid = dit[0]
                device = dit[1]
                VppPCIUtil.vpp_create_interface(interfaces, dvid, device)
            node['interfaces'] = interfaces

            print "\nThese device(s) will be used by VPP, please",
            print "rerun this option if this is incorrect.\n"
            VppPCIUtil.show_vpp_devices(dpdk_devices, show_interfaces=False)

        self._update_auto_config()
        self.updateconfig()

    def modify_huge_pages(self):
        """
        Modify the huge page configuration, asking for the user for the values.

        """

        for i in self._nodes.items():
            node = i[1]

            total = node['hugepages']['actual_total']
            free = node['hugepages']['free']
            size = node['hugepages']['size']
            memfree = node['hugepages']['memfree'].split(' ')[0]
            hugesize = int(size.split(' ')[0])
            # The max number of huge pages should be no more than
            # 70% of total free memory
            maxpages = (int(memfree) * MAX_PERCENT_FOR_HUGE_PAGES / 100) / hugesize
            print "\nThere currently {} {} huge pages free.". \
                format(free, size)
            question = "Do you want to reconfigure the number of "
            question += "huge pages [y/N]? "
            answer = self._ask_user_yn(question, 'n')
            if answer == 'n':
                node['hugepages']['total'] = total
                continue

            print "\nThere currently a total of {} huge pages.". \
                format(total)
            question = \
                "How many huge pages do you want [{} - {}][{}]? ". \
                format(MIN_TOTAL_HUGE_PAGES, maxpages, MIN_TOTAL_HUGE_PAGES)
            answer = self._ask_user_range(question, 1024, maxpages, 1024)
            node['hugepages']['total'] = str(answer)

        # Update auto-config.yaml
        self._update_auto_config()

        # Rediscover just the hugepages
        self.get_hugepages()

    def get_tcp_params(self):
        """
        Get the tcp configuration

        """
        # maybe nothing to do here?
        self.updateconfig()

    def acquire_tcp_params(self):
        """
        Ask the user for TCP stack configuration parameters

        """

        for i in self._nodes.items():
            node = i[1]

            question = "\nHow many active-open / tcp client sessions are expected "
            question = question + "[0-10000000][0]? "
            answer = self._ask_user_range(question, 0, 10000000, 0)
            # Less than 10K is equivalent to 0
            if int(answer) < 10000:
                answer = 0
            node['tcp']['active_open_sessions'] = answer

            question = "How many passive-open / tcp server sessions are expected "
            question = question + "[0-10000000][0]? "
            answer = self._ask_user_range(question, 0, 10000000, 0)
            # Less than 10K is equivalent to 0
            if int(answer) < 10000:
                answer = 0
            node['tcp']['passive_open_sessions'] = answer

        # Update auto-config.yaml
        self._update_auto_config()

        # Rediscover tcp parameters
        self.get_tcp_params()

    @staticmethod
    def patch_qemu(node):
        """
        Patch qemu with the correct patches.

        :param node: Node dictionary
        :type node: dict
        """

        print '\nWe are patching the node "{}":\n'.format(node['host'])
        QemuUtils.build_qemu(node, force_install=True, apply_patch=True)

    @staticmethod
    def cpu_info(node):
        """
        print the CPU information

        """

        cpu = CpuUtils.get_cpu_info_per_node(node)

        item = 'Model name'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'CPU(s)'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'Thread(s) per core'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'Core(s) per socket'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'Socket(s)'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'NUMA node(s)'
        numa_nodes = 0
        if item in cpu:
            numa_nodes = int(cpu[item])
        for i in xrange(0, numa_nodes):
            item = "NUMA node{} CPU(s)".format(i)
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'CPU max MHz'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])
        item = 'CPU min MHz'
        if item in cpu:
            print "{:>20}:    {}".format(item, cpu[item])

        if node['cpu']['smt_enabled']:
            smt = 'Enabled'
        else:
            smt = 'Disabled'
        print "{:>20}:    {}".format('SMT', smt)

        # VPP Threads
        print "\nVPP Threads: (Name: Cpu Number)"
        vpp_processes = cpu['vpp_processes']
        for i in vpp_processes.items():
            print "  {:10}: {:4}".format(i[0], i[1])

    @staticmethod
    def device_info(node):
        """
        Show the device information.

        """

        if 'cpu' in node and 'total_mbufs' in node['cpu']:
            total_mbufs = node['cpu']['total_mbufs']
            if total_mbufs is not 0:
                print "Total Number of Buffers: {}".format(total_mbufs)

        vpp = VppPCIUtil(node)
        vpp.get_all_devices()
        linkup_devs = vpp.get_link_up_devices()
        if len(linkup_devs):
            print ("\nDevices with link up (can not be used with VPP):")
            vpp.show_vpp_devices(linkup_devs, show_header=False)
            # for dev in linkup_devs:
            #    print ("    " + dev)
        kernel_devs = vpp.get_kernel_devices()
        if len(kernel_devs):
            print ("\nDevices bound to kernel drivers:")
            vpp.show_vpp_devices(kernel_devs, show_header=False)
        else:
            print ("\nNo devices bound to kernel drivers")

        dpdk_devs = vpp.get_dpdk_devices()
        if len(dpdk_devs):
            print ("\nDevices bound to DPDK drivers:")
            vpp.show_vpp_devices(dpdk_devs, show_interfaces=True,
                                 show_header=False)
        else:
            print ("\nNo devices bound to DPDK drivers")

        vpputl = VPPUtil()
        interfaces = vpputl.get_hardware(node)
        if interfaces == {}:
            return

        print ("\nDevices in use by VPP:")

        if len(interfaces.items()) < 2:
            print ("None")
            return

        print "{:30} {:6} {:4} {:7} {:4} {:7}". \
            format('Name', 'Socket', 'RXQs',
                   'RXDescs', 'TXQs', 'TXDescs')
        for intf in sorted(interfaces.items()):
            name = intf[0]
            value = intf[1]
            if name == 'local0':
                continue
            socket = rx_qs = rx_ds = tx_qs = tx_ds = ''
            if 'cpu socket' in value:
                socket = int(value['cpu socket'])
            if 'rx queues' in value:
                rx_qs = int(value['rx queues'])
            if 'rx descs' in value:
                rx_ds = int(value['rx descs'])
            if 'tx queues' in value:
                tx_qs = int(value['tx queues'])
            if 'tx descs' in value:
                tx_ds = int(value['tx descs'])

            print ("{:30} {:>6} {:>4} {:>7} {:>4} {:>7}".
                   format(name, socket, rx_qs, rx_ds, tx_qs, tx_ds))

    @staticmethod
    def hugepage_info(node):
        """
        Show the huge page information.

        """

        hpg = VppHugePageUtil(node)
        hpg.show_huge_pages()

    @staticmethod
    def min_system_resources(node):
        """
        Check the system for basic minimum resources, return true if
        there is enough.

        :returns: boolean
        :rtype: dict
        """

        min_sys_res = True

        # CPUs
        if 'layout' in node['cpu']:
            total_cpus = len(node['cpu']['layout'])
            if total_cpus < 2:
                print "\nThere is only {} CPU(s) available on this system.".format(total_cpus)
                print "This is not enough to run VPP."
                min_sys_res = False

        # System Memory
        if 'free' in node['hugepages'] and \
                'memfree' in node['hugepages'] and \
                'size' in node['hugepages']:
            free = node['hugepages']['free']
            memfree = float(node['hugepages']['memfree'].split(' ')[0])
            hugesize = float(node['hugepages']['size'].split(' ')[0])

            memhugepages = MIN_TOTAL_HUGE_PAGES * hugesize
            percentmemhugepages = (memhugepages / memfree) * 100
            if free is '0' and \
                    percentmemhugepages > MAX_PERCENT_FOR_HUGE_PAGES:
                print "\nThe System has only {} of free memory.".format(int(memfree))
                print "You will not be able to allocate enough Huge Pages for VPP."
                min_sys_res = False

        return min_sys_res

    def sys_info(self):
        """
        Print the system information

        """

        for i in self._nodes.items():
            print "\n=============================="
            name = i[0]
            node = i[1]

            print "NODE: {}\n".format(name)

            # CPU
            print "CPU:"
            self.cpu_info(node)

            # Grub
            print "\nGrub Command Line:"
            if 'grub' in node:
                print \
                    "  Current: {}".format(
                        node['grub']['current_cmdline'])
                print \
                    "  Configured: {}".format(
                        node['grub']['default_cmdline'])

            # Huge Pages
            print "\nHuge Pages:"
            self.hugepage_info(node)

            # Devices
            print "\nDevices:"
            self.device_info(node)

            # Status
            print "\nVPP Service Status:"
            state, errors = VPPUtil.status(node)
            print "  {}".format(state)
            for e in errors:
                print "  {}".format(e)

            # Minimum system resources
            self.min_system_resources(node)

            print "\n=============================="

    def _ipv4_interface_setup_questions(self, node):
        """
        Ask the user some questions and get a list of interfaces
        and IPv4 addresses associated with those interfaces

        :param node: Node dictionary.
        :type node: dict
        :returns: A list or interfaces with ip addresses
        :rtype: dict
        """

        vpputl = VPPUtil()
        interfaces = vpputl.get_hardware(node)
        if interfaces == {}:
            return

        interfaces_with_ip = []
        for intf in sorted(interfaces.items()):
            name = intf[0]
            if name == 'local0':
                continue

            question = "Would you like add address to interface {} [Y/n]? ".format(name)
            answer = self._ask_user_yn(question, 'y')
            if answer == 'y':
                address = {}
                addr = self._ask_user_ipv4()
                address['name'] = name
                address['addr'] = addr
                interfaces_with_ip.append(address)

        return interfaces_with_ip

    def ipv4_interface_setup(self):
        """
        After asking the user some questions, get a list of interfaces
        and IPv4 addresses associated with those interfaces

        """

        for i in self._nodes.items():
            node = i[1]

            # Show the current interfaces with IP addresses
            current_ints = VPPUtil.get_int_ip(node)
            if current_ints is not {}:
                print ("\nThese are the current interfaces with IP addresses:")
                for items in sorted(current_ints.items()):
                    name = items[0]
                    value = items[1]
                    if 'address' not in value:
                        address = 'Not Set'
                    else:
                        address = value['address']
                    print ("{:30} {:20} {:10}".format(name, address, value['state']))
                question = "\nWould you like to keep this configuration [Y/n]? "
                answer = self._ask_user_yn(question, 'y')
                if answer == 'y':
                    continue
            else:
                print ("\nThere are currently no interfaces with IP addresses.")

            # Create a script that add the ip addresses to the interfaces
            # and brings the interfaces up
            ints_with_addrs = self._ipv4_interface_setup_questions(node)
            content = ''
            for ints in ints_with_addrs:
                name = ints['name']
                addr = ints['addr']
                setipstr = 'set int ip address {} {}\n'.format(name, addr)
                setintupstr = 'set int state {} up\n'.format(name)
                content += setipstr + setintupstr

            # Write the content to the script
            rootdir = node['rootdir']
            filename = rootdir + '/vpp/vpp-config/scripts/set_int_ipv4_and_up'
            with open(filename, 'w+') as sfile:
                sfile.write(content)

            # Execute the script
            cmd = 'vppctl exec {}'.format(filename)
            (ret, stdout, stderr) = VPPUtil.exec_command(cmd)
            if ret != 0:
                logging.debug(stderr)

            print("\nA script as been created at {}".format(filename))
            print("This script can be run using the following:")
            print("vppctl exec {}\n".format(filename))

    def _create_vints_questions(self, node):
        """
        Ask the user some questions and get a list of interfaces
        and IPv4 addresses associated with those interfaces

        :param node: Node dictionary.
        :type node: dict
        :returns: A list or interfaces with ip addresses
        :rtype: list
        """

        vpputl = VPPUtil()
        interfaces = vpputl.get_hardware(node)
        if interfaces == {}:
            return []

        # First delete all the Virtual interfaces
        for intf in sorted(interfaces.items()):
            name = intf[0]
            if name[:7] == 'Virtual':
                cmd = 'vppctl delete vhost-user {}'.format(name)
                (ret, stdout, stderr) = vpputl.exec_command(cmd)
                if ret != 0:
                    logging.debug('{} failed on node {} {}'.format(
                        cmd, node['host'], stderr))

        # Create a virtual interface, for each interface the user wants to use
        interfaces = vpputl.get_hardware(node)
        if interfaces == {}:
            return []
        interfaces_with_virtual_interfaces = []
        inum = 1
        for intf in sorted(interfaces.items()):
            name = intf[0]
            if name == 'local0':
                continue

            question = "Would you like connect this interface {} to the VM [Y/n]? ".format(name)
            answer = self._ask_user_yn(question, 'y')
            if answer == 'y':
                sockfilename = '/tmp/sock{}.sock'.format(inum)
                if os.path.exists(sockfilename):
                    os.remove(sockfilename)
                cmd = 'vppctl create vhost-user socket {} server'.format(sockfilename)
                (ret, stdout, stderr) = vpputl.exec_command(cmd)
                if ret != 0:
                    raise RuntimeError("Create vhost failed on node {} {}."
                                       .format(node['host'], stderr))
                vintname = stdout.rstrip('\r\n')

                interface = {'name': name, 'virtualinterface': '{}'.format(vintname),
                             'bridge': '{}'.format(inum)}
                inum += 1
                interfaces_with_virtual_interfaces.append(interface)

        return interfaces_with_virtual_interfaces

    def create_and_bridge_virtual_interfaces(self):
        """
        After asking the user some questions, create a VM and connect the interfaces
        to VPP interfaces

        """

        for i in self._nodes.items():
            node = i[1]

            # Show the current bridge and interface configuration
            print "\nThis the current bridge configuration:"
            VPPUtil.show_bridge(node)
            question = "\nWould you like to keep this configuration [Y/n]? "
            answer = self._ask_user_yn(question, 'y')
            if answer == 'y':
                continue

            # Create a script that builds a bridge configuration with physical interfaces
            # and virtual interfaces
            ints_with_vints = self._create_vints_questions(node)
            content = ''
            for intf in ints_with_vints:
                vhoststr = 'comment { The following command creates the socket }\n'
                vhoststr += 'comment { and returns a virtual interface }\n'
                vhoststr += 'comment {{ create vhost-user socket /tmp/sock{}.sock server }}\n'. \
                    format(intf['bridge'])

                setintdnstr = 'set interface state {} down\n'.format(intf['name'])

                setintbrstr = 'set interface l2 bridge {} {}\n'.format(intf['name'], intf['bridge'])
                setvintbrstr = 'set interface l2 bridge {} {}\n'.format(intf['virtualinterface'], intf['bridge'])

                # set interface state VirtualEthernet/0/0/0 up
                setintvststr = 'set interface state {} up\n'.format(intf['virtualinterface'])

                # set interface state VirtualEthernet/0/0/0 down
                setintupstr = 'set interface state {} up\n'.format(intf['name'])

                content += vhoststr + setintdnstr + setintbrstr + setvintbrstr + setintvststr + setintupstr

            # Write the content to the script
            rootdir = node['rootdir']
            filename = rootdir + '/vpp/vpp-config/scripts/create_vms_and_connect_to_vpp'
            with open(filename, 'w+') as sfile:
                sfile.write(content)

            # Execute the script
            cmd = 'vppctl exec {}'.format(filename)
            (ret, stdout, stderr) = VPPUtil.exec_command(cmd)
            if ret != 0:
                logging.debug(stderr)

            print("\nA script as been created at {}".format(filename))
            print("This script can be run using the following:")
            print("vppctl exec {}\n".format(filename))