lib/neutron_plugins/ovn_agent

#!/bin/bash
#
#    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.
#

# Global Sources
# --------------

# There are some ovs functions OVN depends on that must be sourced from
# the ovs neutron plugins.
source ${TOP_DIR}/lib/neutron_plugins/ovs_base
source ${TOP_DIR}/lib/neutron_plugins/openvswitch_agent

# Load devstack ovs compliation and loading functions
source ${TOP_DIR}/lib/neutron_plugins/ovs_source

# Set variables for building OVN from source
OVN_REPO=${OVN_REPO:-https://github.com/ovn-org/ovn.git}
OVN_REPO_NAME=$(basename ${OVN_REPO} | cut -f1 -d'.')
OVN_REPO_NAME=${OVN_REPO_NAME:-ovn}
OVN_BRANCH=${OVN_BRANCH:-v20.06.1}
# The commit removing OVN bits from the OVS tree, it is the commit that is not
# present in OVN tree and is used to distinguish if OVN is part of OVS or not.
# https://github.com/openvswitch/ovs/commit/05bf1dbb98b0635a51f75e268ef8aed27601401d
OVN_SPLIT_HASH=05bf1dbb98b0635a51f75e268ef8aed27601401d

if is_service_enabled tls-proxy; then
    OVN_PROTO=ssl
else
    OVN_PROTO=tcp
fi

# How to connect to ovsdb-server hosting the OVN SB database.
OVN_SB_REMOTE=${OVN_SB_REMOTE:-$OVN_PROTO:$SERVICE_HOST:6642}

# How to connect to ovsdb-server hosting the OVN NB database
OVN_NB_REMOTE=${OVN_NB_REMOTE:-$OVN_PROTO:$SERVICE_HOST:6641}

# ml2/config for neutron_sync_mode
OVN_NEUTRON_SYNC_MODE=${OVN_NEUTRON_SYNC_MODE:-log}

# Configured DNS servers to be used with internal_dns extension, only
# if the subnet DNS is not configured.
OVN_DNS_SERVERS=${OVN_DNS_SERVERS:-8.8.8.8}

# The type of OVN L3 Scheduler to use. The OVN L3 Scheduler determines the
# hypervisor/chassis where a routers gateway should be hosted in OVN. The
# default OVN L3 scheduler is leastloaded
OVN_L3_SCHEDULER=${OVN_L3_SCHEDULER:-leastloaded}

# A UUID to uniquely identify this system.  If one is not specified, a random
# one will be generated.  A randomly generated UUID will be saved in a file
# $OVS_SYSCONFDIR/system-id.conf (typically /etc/openvswitch/system-id.conf)
# so that the same one will be re-used if you re-run DevStack or restart
# Open vSwitch service.
OVN_UUID=${OVN_UUID:-}

# Whether or not to build the openvswitch kernel module from ovs.  This is required
# unless the distro kernel includes ovs+conntrack support.
OVN_BUILD_MODULES=$(trueorfalse False OVN_BUILD_MODULES)
OVN_BUILD_FROM_SOURCE=$(trueorfalse False OVN_BUILD_FROM_SOURCE)
if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
    Q_BUILD_OVS_FROM_GIT=True
fi

# Whether or not to install the ovs python module from ovs source.  This can be
# used to test and validate new ovs python features.  This should only be used
# for development purposes since the ovs python version is controlled by OpenStack
# requirements.
OVN_INSTALL_OVS_PYTHON_MODULE=$(trueorfalse False OVN_INSTALL_OVS_PYTHON_MODULE)

# GENEVE overlay protocol overhead. Defaults to 38 bytes plus the IP version
# overhead (20 bytes for IPv4 (default) or 40 bytes for IPv6) which is determined
# based on the ML2 overlay_ip_version option. The ML2 framework will use this to
# configure the MTU DHCP option.
OVN_GENEVE_OVERHEAD=${OVN_GENEVE_OVERHEAD:-38}

# The log level of the OVN databases (north and south).
# Supported log levels are: off, emer, err, warn, info or dbg.
# More information about log levels can be found at
# http://www.openvswitch.org/support/dist-docs/ovs-appctl.8.txt
OVN_DBS_LOG_LEVEL=${OVN_DBS_LOG_LEVEL:-info}

OVN_META_CONF=$NEUTRON_CONF_DIR/neutron_ovn_metadata_agent.ini
OVN_META_DATA_HOST=${OVN_META_DATA_HOST:-$(ipv6_unquote $SERVICE_HOST)}

# If True (default) the node will be considered a gateway node.
ENABLE_CHASSIS_AS_GW=$(trueorfalse True ENABLE_CHASSIS_AS_GW)
OVN_L3_CREATE_PUBLIC_NETWORK=$(trueorfalse True OVN_L3_CREATE_PUBLIC_NETWORK)

export OVSDB_SERVER_LOCAL_HOST=$SERVICE_LOCAL_HOST
if [[ "$SERVICE_IP_VERSION" == 6 ]]; then
    OVSDB_SERVER_LOCAL_HOST=[$OVSDB_SERVER_LOCAL_HOST]
fi

OVN_IGMP_SNOOPING_ENABLE=$(trueorfalse False OVN_IGMP_SNOOPING_ENABLE)

OVS_PREFIX=
if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
    OVS_PREFIX=/usr/local
fi
OVS_SBINDIR=$OVS_PREFIX/sbin
OVS_BINDIR=$OVS_PREFIX/bin
OVS_RUNDIR=$OVS_PREFIX/var/run/openvswitch
OVS_SHAREDIR=$OVS_PREFIX/share/openvswitch
OVS_SCRIPTDIR=$OVS_SHAREDIR/scripts
OVS_DATADIR=$DATA_DIR/ovs
OVS_SYSCONFDIR=${OVS_SYSCONFDIR:-$OVS_PREFIX/etc/openvswitch}

OVN_DATADIR=$DATA_DIR/ovn
OVN_SHAREDIR=$OVS_PREFIX/share/ovn
OVN_SCRIPTDIR=$OVN_SHAREDIR/scripts
OVN_RUNDIR=$OVS_PREFIX/var/run/ovn

NEUTRON_OVN_BIN_DIR=$(get_python_exec_prefix)
NEUTRON_OVN_METADATA_BINARY="neutron-ovn-metadata-agent"

STACK_GROUP="$( id --group --name "$STACK_USER" )"

OVN_NORTHD_SERVICE=ovn-northd.service
if is_ubuntu; then
    # The ovn-central.service file on Ubuntu is responsible for starting
    # ovn-northd and the OVN DBs (on CentOS this is done by ovn-northd.service)
    OVN_NORTHD_SERVICE=ovn-central.service
fi
OVSDB_SERVER_SERVICE=ovsdb-server.service
OVS_VSWITCHD_SERVICE=ovs-vswitchd.service
OVN_CONTROLLER_SERVICE=ovn-controller.service
OVN_CONTROLLER_VTEP_SERVICE=ovn-controller-vtep.service
if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
    OVSDB_SERVER_SERVICE=devstack@ovsdb-server.service
    OVS_VSWITCHD_SERVICE=devstack@ovs-vswitchd.service
    OVN_NORTHD_SERVICE=devstack@ovn-northd.service
    OVN_CONTROLLER_SERVICE=devstack@ovn-controller.service
    OVN_CONTROLLER_VTEP_SERVICE=devstack@ovn-controller-vtep.service
fi

# Defaults Overwrite
# ------------------

Q_ML2_PLUGIN_MECHANISM_DRIVERS=${Q_ML2_PLUGIN_MECHANISM_DRIVERS:-ovn,logger}
Q_ML2_PLUGIN_TYPE_DRIVERS=${Q_ML2_PLUGIN_TYPE_DRIVERS:-local,flat,vlan,geneve}
Q_ML2_TENANT_NETWORK_TYPE=${Q_ML2_TENANT_NETWORK_TYPE:-"geneve"}
Q_ML2_PLUGIN_GENEVE_TYPE_OPTIONS=${Q_ML2_PLUGIN_GENEVE_TYPE_OPTIONS:-"vni_ranges=1:65536"}
Q_ML2_PLUGIN_EXT_DRIVERS=${Q_ML2_PLUGIN_EXT_DRIVERS:-port_security,qos}
# this one allows empty:
ML2_L3_PLUGIN=${ML2_L3_PLUGIN-"ovn-router"}

Q_LOG_DRIVER_RATE_LIMIT=${Q_LOG_DRIVER_RATE_LIMIT:-100}
Q_LOG_DRIVER_BURST_LIMIT=${Q_LOG_DRIVER_BURST_LIMIT:-25}
Q_LOG_DRIVER_LOG_BASE=${Q_LOG_DRIVER_LOG_BASE:-acl_log_meter}

# Utility Functions
# -----------------

function wait_for_sock_file {
    local count=0
    while [ ! -S $1 ]; do
        sleep 1
        count=$((count+1))
        if [ "$count" -gt 5 ]; then
            die $LINENO "Socket $1 not found"
        fi
    done
}

function use_new_ovn_repository {
    if [[ "$OVN_BUILD_FROM_SOURCE" == "False" ]]; then
        return 0
    fi
    if [ -z "$is_new_ovn" ]; then
        local ovs_repo_dir=$DEST/$OVS_REPO_NAME
        if [ ! -d $ovs_repo_dir ]; then
            git_timed clone $OVS_REPO $ovs_repo_dir
            pushd $ovs_repo_dir
            git checkout $OVS_BRANCH
            popd
        else
            clone_repository $OVS_REPO $ovs_repo_dir $OVS_BRANCH
        fi
        # Check the split commit exists in the current branch
        pushd $ovs_repo_dir
        git log $OVS_BRANCH --pretty=format:"%H" | grep -q $OVN_SPLIT_HASH
        is_new_ovn=$?
        popd
    fi
    return $is_new_ovn
}

# NOTE(rtheis): Function copied from DevStack _neutron_ovs_base_setup_bridge
# and _neutron_ovs_base_add_bridge with the call to neutron-ovs-cleanup
# removed. The call is not relevant for OVN, as it is specific to the use
# of Neutron's OVS agent and hangs when running stack.sh because
# neutron-ovs-cleanup uses the OVSDB native interface.
function ovn_base_setup_bridge {
    local bridge=$1
    local addbr_cmd="sudo ovs-vsctl --no-wait -- --may-exist add-br $bridge -- set bridge $bridge protocols=OpenFlow13,OpenFlow15"

    if [ "$OVS_DATAPATH_TYPE" != "system" ] ; then
        addbr_cmd="$addbr_cmd -- set Bridge $bridge datapath_type=${OVS_DATAPATH_TYPE}"
    fi

    $addbr_cmd
    sudo ovs-vsctl --no-wait br-set-external-id $bridge bridge-id $bridge
}

function _start_process {
    $SYSTEMCTL daemon-reload
    $SYSTEMCTL enable $1
    $SYSTEMCTL restart $1
}

function _run_process {
    local service=$1
    local cmd="$2"
    local stop_cmd="$3"
    local group=$4
    local user=${5:-$STACK_USER}

    local systemd_service="devstack@$service.service"
    local unit_file="$SYSTEMD_DIR/$systemd_service"
    local environment="OVN_RUNDIR=$OVS_RUNDIR OVN_DBDIR=$OVN_DATADIR OVN_LOGDIR=$LOGDIR OVS_RUNDIR=$OVS_RUNDIR OVS_DBDIR=$OVS_DATADIR OVS_LOGDIR=$LOGDIR"

    echo "Starting $service executed command": $cmd

    write_user_unit_file $systemd_service "$cmd" "$group" "$user"
    iniset -sudo $unit_file "Service" "Type" "forking"
    iniset -sudo $unit_file "Service" "RemainAfterExit" "yes"
    iniset -sudo $unit_file "Service" "KillMode" "mixed"
    iniset -sudo $unit_file "Service" "LimitNOFILE" "65536"
    iniset -sudo $unit_file "Service" "Environment" "$environment"
    if [ -n "$stop_cmd" ]; then
        iniset -sudo $unit_file "Service" "ExecStop" "$stop_cmd"
    fi

    _start_process $systemd_service

    local testcmd="test -e $OVS_RUNDIR/$service.pid"
    test_with_retry "$testcmd" "$service did not start" $SERVICE_TIMEOUT 1
    sudo ovs-appctl -t $service vlog/set console:off syslog:info file:info
}

function clone_repository {
    local repo=$1
    local dir=$2
    local branch=$3
    # Set ERROR_ON_CLONE to false to avoid the need of having the
    # repositories like OVN and OVS in the required_projects of the job
    # definition.
    ERROR_ON_CLONE=false git_clone $repo $dir $branch
}

function create_public_bridge {
    # Create the public bridge that OVN will use
    sudo ovs-vsctl --may-exist add-br $PUBLIC_BRIDGE -- set bridge $PUBLIC_BRIDGE protocols=OpenFlow13,OpenFlow15
    sudo ovs-vsctl set open . external-ids:ovn-bridge-mappings=$PHYSICAL_NETWORK:$PUBLIC_BRIDGE
    _configure_public_network_connectivity
}

function _disable_libvirt_apparmor {
    if ! sudo aa-status --enabled ; then
        return 0
    fi
    # NOTE(arosen): This is used as a work around to allow newer versions
    # of libvirt to work with ovs configured ports. See LP#1466631.
    # requires the apparmor-utils
    install_package apparmor-utils
    # disables apparmor for libvirtd
    sudo aa-complain /etc/apparmor.d/usr.sbin.libvirtd
}


# OVN compilation functions
# -------------------------


# compile_ovn() - Compile OVN from source and load needed modules
#                 Accepts three parameters:
#                   - first optional is False by default and means that
#                     modules are built and installed.
#                   - second optional parameter defines prefix for
#                     ovn compilation
#                   - third optional parameter defines localstatedir for
#                     ovn single machine runtime
function compile_ovn {
    local build_modules=${1:-False}
    local prefix=$2
    local localstatedir=$3

    if [ -n "$prefix" ]; then
        prefix="--prefix=$prefix"
    fi

    if [ -n "$localstatedir" ]; then
        localstatedir="--localstatedir=$localstatedir"
    fi

    clone_repository $OVN_REPO $DEST/$OVN_REPO_NAME $OVN_BRANCH
    pushd $DEST/$OVN_REPO_NAME

    if [ ! -f configure ] ; then
        ./boot.sh
    fi

    if [ ! -f config.status ] || [ configure -nt config.status ] ; then
        ./configure --with-ovs-source=$DEST/$OVS_REPO_NAME $prefix $localstatedir
    fi
    make -j$(($(nproc) + 1))
    sudo make install
    popd
}


# OVN Neutron driver functions
# ----------------------------

# OVN service sanity check
function ovn_sanity_check {
    if is_service_enabled q-agt neutron-agt; then
        die $LINENO "The q-agt/neutron-agt service must be disabled with OVN."
    elif is_service_enabled q-l3 neutron-l3; then
        die $LINENO "The q-l3/neutron-l3 service must be disabled with OVN."
    elif is_service_enabled q-svc neutron-api && [[ ! $Q_ML2_PLUGIN_MECHANISM_DRIVERS =~ "ovn" ]]; then
        die $LINENO "OVN needs to be enabled in \$Q_ML2_PLUGIN_MECHANISM_DRIVERS"
    elif is_service_enabled q-svc neutron-api && [[ ! $Q_ML2_PLUGIN_TYPE_DRIVERS =~ "geneve" ]]; then
        die $LINENO "Geneve needs to be enabled in \$Q_ML2_PLUGIN_TYPE_DRIVERS to be used with OVN"
    fi
}

# install_ovn() - Collect source and prepare
function install_ovn {
    echo "Installing OVN and dependent packages"

    # Check the OVN configuration
    ovn_sanity_check

    # Install tox, used to generate the config (see devstack/override-defaults)
    pip_install tox

    sudo mkdir -p $OVS_RUNDIR
    sudo chown $(whoami) $OVS_RUNDIR
    # NOTE(lucasagomes): To keep things simpler, let's reuse the same
    # RUNDIR for both OVS and OVN. This way we avoid having to specify the
    # --db option in the ovn-{n,s}bctl commands while playing with DevStack
    sudo ln -s $OVS_RUNDIR $OVN_RUNDIR

    if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
        # If OVS is already installed, remove it, because we're about to
        # re-install it from source.
        for package in openvswitch openvswitch-switch openvswitch-common; do
            if is_package_installed $package ; then
                uninstall_package $package
            fi
        done

        remove_ovs_packages
        sudo rm -f $OVS_RUNDIR/*

        compile_ovs $OVN_BUILD_MODULES
        if use_new_ovn_repository; then
            compile_ovn $OVN_BUILD_MODULES
        fi

        sudo mkdir -p $OVS_PREFIX/var/log/openvswitch
        sudo chown $(whoami) $OVS_PREFIX/var/log/openvswitch
        sudo mkdir -p $OVS_PREFIX/var/log/ovn
        sudo chown $(whoami) $OVS_PREFIX/var/log/ovn
    else
        fixup_ovn_centos
        install_package $(get_packages openvswitch)
        install_package $(get_packages ovn)
    fi

    # Ensure that the OVS commands are accessible in the PATH
    export PATH=$OVS_BINDIR:$PATH

    # Archive log files and create new
    local log_archive_dir=$LOGDIR/archive
    mkdir -p $log_archive_dir
    for logfile in ovs-vswitchd.log ovn-northd.log ovn-controller.log ovn-controller-vtep.log ovs-vtep.log ovsdb-server.log ovsdb-server-nb.log ovsdb-server-sb.log; do
        if [ -f "$LOGDIR/$logfile" ] ; then
            mv "$LOGDIR/$logfile"  "$log_archive_dir/$logfile.${CURRENT_LOG_TIME}"
        fi
    done

    # Install ovsdbapp from source if requested
    if use_library_from_git "ovsdbapp"; then
        git_clone_by_name "ovsdbapp"
        setup_dev_lib "ovsdbapp"
    fi

    # Install ovs python module from ovs source.
    if [[ "$OVN_INSTALL_OVS_PYTHON_MODULE" == "True" ]]; then
        sudo pip uninstall -y ovs
        # Clone the OVS repository if it's not yet present
        clone_repository $OVS_REPO $DEST/$OVS_REPO_NAME $OVS_BRANCH
        sudo pip install -e $DEST/$OVS_REPO_NAME/python
    fi
}

# filter_network_api_extensions() - Remove non-supported API extensions by
# the OVN driver from the list of enabled API extensions
function filter_network_api_extensions {
    SUPPORTED_NETWORK_API_EXTENSIONS=$($PYTHON -c \
        'from neutron.common.ovn import extensions ;\
        print(",".join(extensions.ML2_SUPPORTED_API_EXTENSIONS))')
    SUPPORTED_NETWORK_API_EXTENSIONS=$SUPPORTED_NETWORK_API_EXTENSIONS,$($PYTHON -c \
        'from neutron.common.ovn import extensions ;\
        print(",".join(extensions.ML2_SUPPORTED_API_EXTENSIONS_OVN_L3))')
    if is_service_enabled q-qos neutron-qos ; then
        SUPPORTED_NETWORK_API_EXTENSIONS="$SUPPORTED_NETWORK_API_EXTENSIONS,qos"
    fi
    NETWORK_API_EXTENSIONS=${NETWORK_API_EXTENSIONS:-$SUPPORTED_NETWORK_API_EXTENSIONS}
    extensions=$(echo $NETWORK_API_EXTENSIONS | tr ', ' '\n' | sort -u)
    supported_ext=$(echo $SUPPORTED_NETWORK_API_EXTENSIONS | tr ', ' '\n' | sort -u)
    enabled_ext=$(comm -12 <(echo -e "$extensions") <(echo -e "$supported_ext"))
    disabled_ext=$(comm -3 <(echo -e "$extensions") <(echo -e "$enabled_ext"))

    # Log a message in case some extensions had to be disabled because
    # they are not supported by the OVN driver
    if [ ! -z "$disabled_ext" ]; then
        _disabled=$(echo $disabled_ext | tr ' ' ',')
        echo "The folling network API extensions have been disabled because they are not supported by OVN: $_disabled"
    fi

    # Export the final list of extensions that have been enabled and are
    # supported by OVN
    export NETWORK_API_EXTENSIONS=$(echo $enabled_ext | tr ' ' ',')
}

function configure_ovn_plugin {
    echo "Configuring Neutron for OVN"

    if is_service_enabled q-svc ; then
        filter_network_api_extensions
        populate_ml2_config /$Q_PLUGIN_CONF_FILE ml2_type_geneve max_header_size=$OVN_GENEVE_OVERHEAD
        populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_nb_connection="$OVN_NB_REMOTE"
        populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_sb_connection="$OVN_SB_REMOTE"
        if is_service_enabled tls-proxy; then
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_sb_ca_cert="$INT_CA_DIR/ca-chain.pem"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_sb_certificate="$INT_CA_DIR/$DEVSTACK_CERT_NAME.crt"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_sb_private_key="$INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_nb_ca_cert="$INT_CA_DIR/ca-chain.pem"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_nb_certificate="$INT_CA_DIR/$DEVSTACK_CERT_NAME.crt"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_nb_private_key="$INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key"
        fi
        populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn neutron_sync_mode="$OVN_NEUTRON_SYNC_MODE"
        populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_l3_scheduler="$OVN_L3_SCHEDULER"
        populate_ml2_config /$Q_PLUGIN_CONF_FILE securitygroup enable_security_group="$Q_USE_SECGROUP"
        inicomment /$Q_PLUGIN_CONF_FILE securitygroup firewall_driver

        if is_service_enabled q-log neutron-log; then
            populate_ml2_config /$Q_PLUGIN_CONF_FILE network_log rate_limit="$Q_LOG_DRIVER_RATE_LIMIT"
            populate_ml2_config /$Q_PLUGIN_CONF_FILE network_log burst_limit="$Q_LOG_DRIVER_BURST_LIMIT"
            inicomment /$Q_PLUGIN_CONF_FILE network_log local_output_log_base="$Q_LOG_DRIVER_LOG_BASE"
        fi

        if is_service_enabled q-ovn-metadata-agent; then
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_metadata_enabled=True
        else
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn ovn_metadata_enabled=False
        fi

        if is_service_enabled q-dns neutron-dns ; then
            iniset $NEUTRON_CONF DEFAULT dns_domain openstackgate.local
            populate_ml2_config /$Q_PLUGIN_CONF_FILE ovn dns_servers="$OVN_DNS_SERVERS"
        fi

        iniset $NEUTRON_CONF ovs igmp_snooping_enable $OVN_IGMP_SNOOPING_ENABLE
    fi

    if is_service_enabled q-dhcp neutron-dhcp ; then
        iniset $NEUTRON_CONF DEFAULT dhcp_agent_notification True
    else
        iniset $NEUTRON_CONF DEFAULT dhcp_agent_notification False
    fi

    if is_service_enabled n-api-meta ; then
        if is_service_enabled q-ovn-metadata-agent ; then
            iniset $NOVA_CONF neutron service_metadata_proxy True
        fi
    fi
}

function configure_ovn {
    echo "Configuring OVN"

    if [ -z "$OVN_UUID" ] ; then
        if [ -f $OVS_SYSCONFDIR/system-id.conf ]; then
            OVN_UUID=$(cat $OVS_SYSCONFDIR/system-id.conf)
        else
            OVN_UUID=$(uuidgen)
            echo $OVN_UUID | sudo tee $OVS_SYSCONFDIR/system-id.conf
        fi
    else
        local ovs_uuid
        ovs_uuid=$(cat $OVS_SYSCONFDIR/system-id.conf)
        if [ "$ovs_uuid" != $OVN_UUID ]; then
            echo $OVN_UUID | sudo tee $OVS_SYSCONFDIR/system-id.conf
        fi
    fi

    # Erase the pre-set configurations from packages. DevStack will
    # configure OVS and OVN accordingly for its use.
    if [[ "$OVN_BUILD_FROM_SOURCE" == "False" ]] && is_fedora; then
        sudo truncate -s 0 /etc/openvswitch/default.conf
        sudo truncate -s 0 /etc/sysconfig/openvswitch
        sudo truncate -s 0 /etc/sysconfig/ovn
    fi

    # Metadata
    if is_service_enabled q-ovn-metadata-agent && is_service_enabled ovn-controller; then
        sudo install -d -o $STACK_USER $NEUTRON_CONF_DIR

        mkdir -p $NEUTRON_DIR/etc/neutron/plugins/ml2
        (cd $NEUTRON_DIR && exec ./tools/generate_config_file_samples.sh)

        cp $NEUTRON_DIR/etc/neutron_ovn_metadata_agent.ini.sample $OVN_META_CONF
        configure_root_helper_options $OVN_META_CONF

        iniset $OVN_META_CONF DEFAULT debug $ENABLE_DEBUG_LOG_LEVEL
        iniset $OVN_META_CONF DEFAULT nova_metadata_host $OVN_META_DATA_HOST
        iniset $OVN_META_CONF DEFAULT metadata_workers $API_WORKERS
        iniset $OVN_META_CONF DEFAULT state_path $NEUTRON_STATE_PATH
        iniset $OVN_META_CONF ovs ovsdb_connection tcp:$OVSDB_SERVER_LOCAL_HOST:6640
        iniset $OVN_META_CONF ovn ovn_sb_connection $OVN_SB_REMOTE
        if is_service_enabled tls-proxy; then
            iniset $OVN_META_CONF ovn \
                ovn_sb_ca_cert $INT_CA_DIR/ca-chain.pem
            iniset $OVN_META_CONF ovn \
                ovn_sb_certificate $INT_CA_DIR/$DEVSTACK_CERT_NAME.crt
            iniset $OVN_META_CONF ovn \
                ovn_sb_private_key $INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key
        fi
    fi
}

function init_ovn {
    # clean up from previous (possibly aborted) runs
    # create required data files

    # Assumption: this is a dedicated test system and there is nothing important
    # in the ovn, ovn-nb, or ovs databases.  We're going to trash them and
    # create new ones on each devstack run.

    _disable_libvirt_apparmor

    mkdir -p $OVN_DATADIR
    mkdir -p $OVS_DATADIR

    rm -f $OVS_DATADIR/*.db
    rm -f $OVS_DATADIR/.*.db.~lock~
    rm -f $OVN_DATADIR/*.db
    rm -f $OVN_DATADIR/.*.db.~lock~
}

function _start_ovs {
    echo "Starting OVS"
    if is_service_enabled ovn-controller ovn-controller-vtep ovn-northd; then
        # ovsdb-server and ovs-vswitchd are used privately in OVN as openvswitch service names.
        enable_service ovsdb-server
        enable_service ovs-vswitchd

        if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
            if [ ! -f $OVS_DATADIR/conf.db ]; then
                ovsdb-tool create $OVS_DATADIR/conf.db $OVS_SHAREDIR/vswitch.ovsschema
            fi

            if is_service_enabled ovn-controller-vtep; then
                if [ ! -f $OVS_DATADIR/vtep.db ]; then
                    ovsdb-tool create $OVS_DATADIR/vtep.db $OVS_SHAREDIR/vtep.ovsschema
                fi
            fi

            local dbcmd="$OVS_SBINDIR/ovsdb-server --remote=punix:$OVS_RUNDIR/db.sock --remote=ptcp:6640:$OVSDB_SERVER_LOCAL_HOST --pidfile --detach --log-file"
            dbcmd+=" --remote=db:Open_vSwitch,Open_vSwitch,manager_options"
            if is_service_enabled ovn-controller-vtep; then
                dbcmd+=" --remote=db:hardware_vtep,Global,managers $OVS_DATADIR/vtep.db"
            fi
            dbcmd+=" $OVS_DATADIR/conf.db"
            _run_process ovsdb-server "$dbcmd"

            # Note: ovn-controller will create and configure br-int once it is started.
            # So, no need to create it now because nothing depends on that bridge here.
            local ovscmd="$OVS_SBINDIR/ovs-vswitchd --log-file --pidfile --detach"
            _run_process ovs-vswitchd "$ovscmd" "" "$STACK_GROUP" "root"
        else
            _start_process "$OVSDB_SERVER_SERVICE"
            _start_process "$OVS_VSWITCHD_SERVICE"
        fi

        echo "Configuring OVSDB"
        if is_service_enabled tls-proxy; then
            sudo ovs-vsctl --no-wait set-ssl \
                $INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key \
                $INT_CA_DIR/$DEVSTACK_CERT_NAME.crt \
                $INT_CA_DIR/ca-chain.pem
        fi

        sudo ovs-vsctl --no-wait set-manager ptcp:6640:$OVSDB_SERVER_LOCAL_HOST
        sudo ovs-vsctl --no-wait set open_vswitch . system-type="devstack"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:system-id="$OVN_UUID"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:ovn-remote="$OVN_SB_REMOTE"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:ovn-bridge="br-int"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:ovn-encap-type="geneve"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:ovn-encap-ip="$HOST_IP"
        sudo ovs-vsctl --no-wait set open_vswitch . external-ids:hostname="$LOCAL_HOSTNAME"
        # Select this chassis to host gateway routers
        if [[ "$ENABLE_CHASSIS_AS_GW" == "True" ]]; then
            sudo ovs-vsctl --no-wait set open_vswitch . external-ids:ovn-cms-options="enable-chassis-as-gw"
        fi

        if is_provider_network || [[ $Q_USE_PROVIDERNET_FOR_PUBLIC == "True" ]]; then
            ovn_base_setup_bridge $OVS_PHYSICAL_BRIDGE
            sudo ovs-vsctl set open . external-ids:ovn-bridge-mappings=${PHYSICAL_NETWORK}:${OVS_PHYSICAL_BRIDGE}
        fi

        if is_service_enabled ovn-controller-vtep ; then
            ovn_base_setup_bridge br-v
            vtep-ctl add-ps br-v
            vtep-ctl set Physical_Switch br-v tunnel_ips=$HOST_IP

            enable_service ovs-vtep
            local vtepcmd="$OVS_SCRIPTDIR/ovs-vtep --log-file --pidfile --detach br-v"
            _run_process ovs-vtep "$vtepcmd" "" "$STACK_GROUP" "root"

            vtep-ctl set-manager tcp:$HOST_IP:6640
        fi
    fi
}

function _start_ovn_services {
    _start_process "$OVSDB_SERVER_SERVICE"
    _start_process "$OVS_VSWITCHD_SERVICE"

    if is_service_enabled ovn-northd ; then
        _start_process "$OVN_NORTHD_SERVICE"
    fi
    if is_service_enabled ovn-controller ; then
        _start_process "$OVN_CONTROLLER_SERVICE"
    fi
    if is_service_enabled ovn-controller-vtep ; then
        _start_process "$OVN_CONTROLLER_VTEP_SERVICE"
    fi
    if is_service_enabled ovs-vtep ; then
        _start_process "devstack@ovs-vtep.service"
    fi
    if is_service_enabled q-ovn-metadata-agent; then
        _start_process "devstack@q-ovn-metadata-agent.service"
    fi
}

# start_ovn() - Start running processes, including screen
function start_ovn {
    echo "Starting OVN"

    _start_ovs

    local SCRIPTDIR=$OVN_SCRIPTDIR
    if ! use_new_ovn_repository; then
        SCRIPTDIR=$OVS_SCRIPTDIR
    fi

    if is_service_enabled ovn-northd ; then
        if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
            local cmd="/bin/bash $SCRIPTDIR/ovn-ctl --no-monitor start_northd"
            local stop_cmd="/bin/bash $SCRIPTDIR/ovn-ctl stop_northd"

            _run_process ovn-northd "$cmd" "$stop_cmd"
        else
            _start_process "$OVN_NORTHD_SERVICE"
        fi

        # Wait for the service to be ready
        wait_for_sock_file $OVS_RUNDIR/ovnnb_db.sock
        wait_for_sock_file $OVS_RUNDIR/ovnsb_db.sock

        if is_service_enabled tls-proxy; then
            sudo ovn-nbctl --db=unix:$OVS_RUNDIR/ovnnb_db.sock set-ssl $INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key $INT_CA_DIR/$DEVSTACK_CERT_NAME.crt $INT_CA_DIR/ca-chain.pem
            sudo ovn-sbctl --db=unix:$OVS_RUNDIR/ovnsb_db.sock set-ssl $INT_CA_DIR/private/$DEVSTACK_CERT_NAME.key $INT_CA_DIR/$DEVSTACK_CERT_NAME.crt $INT_CA_DIR/ca-chain.pem
        fi
        sudo ovn-nbctl --db=unix:$OVS_RUNDIR/ovnnb_db.sock set-connection p${OVN_PROTO}:6641:$SERVICE_LISTEN_ADDRESS -- set connection . inactivity_probe=60000
        sudo ovn-sbctl --db=unix:$OVS_RUNDIR/ovnsb_db.sock set-connection p${OVN_PROTO}:6642:$SERVICE_LISTEN_ADDRESS -- set connection . inactivity_probe=60000
        sudo ovs-appctl -t $OVS_RUNDIR/ovnnb_db.ctl vlog/set console:off syslog:$OVN_DBS_LOG_LEVEL file:$OVN_DBS_LOG_LEVEL
        sudo ovs-appctl -t $OVS_RUNDIR/ovnsb_db.ctl vlog/set console:off syslog:$OVN_DBS_LOG_LEVEL file:$OVN_DBS_LOG_LEVEL
    fi

    if is_service_enabled ovn-controller ; then
        if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
            local cmd="/bin/bash $SCRIPTDIR/ovn-ctl --no-monitor start_controller"
            local stop_cmd="/bin/bash $SCRIPTDIR/ovn-ctl stop_controller"

            _run_process ovn-controller "$cmd" "$stop_cmd" "$STACK_GROUP" "root"
        else
            _start_process "$OVN_CONTROLLER_SERVICE"
        fi
    fi

    if is_service_enabled ovn-controller-vtep ; then
        if [[ "$OVN_BUILD_FROM_SOURCE" == "True" ]]; then
            local cmd="$OVS_BINDIR/ovn-controller-vtep --log-file --pidfile --detach --ovnsb-db=$OVN_SB_REMOTE"
            _run_process ovn-controller-vtep "$cmd" "" "$STACK_GROUP" "root"
        else
            _start_process "$OVN_CONTROLLER_VTEP_SERVICE"
        fi
    fi

    if is_service_enabled q-ovn-metadata-agent; then
        run_process q-ovn-metadata-agent "$NEUTRON_OVN_BIN_DIR/$NEUTRON_OVN_METADATA_BINARY --config-file $OVN_META_CONF"
        # Format logging
        setup_logging $OVN_META_CONF
    fi

    _start_ovn_services
}

function _stop_ovs_dp {
    sudo ovs-dpctl dump-dps | sudo xargs -n1 ovs-dpctl del-dp
    modprobe -q -r vport_geneve vport_vxlan openvswitch || true
}

function _stop_process {
    local service=$1
    echo "Stopping process $service"
    if $SYSTEMCTL is-enabled $service; then
        $SYSTEMCTL stop $service
        $SYSTEMCTL disable $service
    fi
}

function stop_ovn {
    if is_service_enabled q-ovn-metadata-agent; then
        sudo pkill -9 -f haproxy || :
        _stop_process "devstack@q-ovn-metadata-agent.service"
    fi
    if is_service_enabled ovn-controller-vtep ; then
        _stop_process "$OVN_CONTROLLER_VTEP_SERVICE"
    fi
    if is_service_enabled ovn-controller ; then
        _stop_process "$OVN_CONTROLLER_SERVICE"
    fi
    if is_service_enabled ovn-northd ; then
        _stop_process "$OVN_NORTHD_SERVICE"
    fi
    if is_service_enabled ovs-vtep ; then
        _stop_process "devstack@ovs-vtep.service"
    fi

    _stop_process "$OVS_VSWITCHD_SERVICE"
    _stop_process "$OVSDB_SERVER_SERVICE"

    _stop_ovs_dp
}

function _cleanup {
    local path=${1:-$DEST/$OVN_REPO_NAME}
    pushd $path
    cd $path
    sudo make uninstall
    sudo make distclean
    popd
}

# cleanup_ovn() - Remove residual data files, anything left over from previous
# runs that a clean run would need to clean up
function cleanup_ovn {
    local ovn_path=$DEST/$OVN_REPO_NAME
    local ovs_path=$DEST/$OVS_REPO_NAME

    if [ -d $ovn_path ]; then
        _cleanup $ovn_path
    fi

    if [ -d $ovs_path ]; then
        _cleanup $ovs_path
    fi

    sudo rm -f $OVN_RUNDIR
}