I'm trying to building a devstack on my ubuntu20.04.
About the network configuration, I used linuxbridge as Q_AGENT and the neutron can't be started. In the log, 'Neutron did not start' occurred. It shows that neutron service can't be started Here is the log.
+ lib/neutron-legacy:start_neutron_service_and_check:559 : echo 'Waiting for Neutron to start...'
Waiting for Neutron to start...
+ lib/neutron-legacy:start_neutron_service_and_check:561 : local 'testcmd=wget --no-proxy -q -O- http://ip:9696'
+ lib/neutron-legacy:start_neutron_service_and_check:562 : test_with_retry 'wget --no-proxy -q -O- http://ip:9696' 'Neutron did not start' 60
+ functions-common:test_with_retry:2364 : local 'testcmd=wget --no-proxy -q -O- http://ip:9696'
+ functions-common:test_with_retry:2365 : local 'failmsg=Neutron did not start'
+ functions-common:test_with_retry:2366 : local until=60
+ functions-common:test_with_retry:2367 : local sleep=0.5
+ functions-common:test_with_retry:2369 : time_start test_with_retry
+ functions-common:time_start:2412 : local name=test_with_retry
+ functions-common:time_start:2413 : local start_time=
+ functions-common:time_start:2414 : [[ -n '' ]]
++ functions-common:time_start:2417 : date +%s%3N
+ functions-common:time_start:2417 : _TIME_START[$name]=1654506568567
+ functions-common:test_with_retry:2370 : timeout 60 sh -c 'while ! wget --no-proxy -q -O- http://ip:9696; do sleep 0.5; done'
+ functions-common:test_with_retry:2371 : die 2371 'Neutron did not start'
+ functions-common:die:264 : local exitcode=0
[Call Trace]
./stack.sh:1286:start_neutron_service_and_check
/opt/stack/new/devstack/lib/neutron-legacy:562:test_with_retry
/opt/stack/new/devstack/functions-common:2371:die
[ERROR] /opt/stack/new/devstack/functions-common:2371 Neutron did not start
exit_trap: cleaning up child processes
And the configuration about my local.conf is following.
[[local|localrc]]
#=== START ===
USE_PYTHON3=True
PYTHON3_VERSION=3.8
#=== END ===
FORCE=yes
Q_USE_SECGROUP=True
Q_USE_PROVIDERNET_FOR_PUBLIC=True
Q_AGENT=linuxbridge
FLAT_INTERFACE=ens3
Q_PLUGIN=ml2
Q_ML2_PLUGIN_MECHANISM_DRIVERS=openvswitch
Q_ML2_PLUGIN_TYPE_DRIVERS=flat,vlan
ML2_VLAN_RANGES=ens3:2000:2999
ENABLE_TENANT_VLANS=True
PHYSICAL_NETWORK=ens3
OVS_PHYSICAL_BRIDGE=br-ex
OVS_BRIDGE_MAPPINGS=ens3:br-ex
USE_PYTHON3=True
Q_USE_DEBUG_COMMAND=True
NETWORK_GATEWAY=gateway_ip
USE_SCREEN=False
DEST=/opt/stack/new
DATA_DIR=/opt/stack/data
ACTIVE_TIMEOUT=90
BOOT_TIMEOUT=90
ASSOCIATE_TIMEOUT=60
TERMINATE_TIMEOUT=60
MYSQL_PASSWORD=secretmysql
DATABASE_PASSWORD=secretdatabase
RABBIT_PASSWORD=secretrabbit
ADMIN_PASSWORD=secretadmin
SERVICE_PASSWORD=secretservice
SERVICE_TOKEN=111222333444
SWIFT_HASH=1234123412341234
ROOTSLEEP=0
ERROR_ON_CLONE=True
INSTALL_TEMPEST=False
NOVNC_FROM_PACKAGE=True
ENABLED_SERVICES=c-api,c-bak,c-sch,c-vol,dstat,etcd3,g-api,g-reg,key,mysql,n-api,n-api-meta,n-cond,n-cpu,n-novnc,n-sch,placement-api,q-agt,q-l3,q-metering,q-svc,q-dhcp,q-meta,rabbit,s-account,s-container,s-object,s-proxy,tempest
SKIP_EXERCISES=boot_from_volume,bundle,client-env,euca
SYSLOG=False
SCREEN_LOGDIR=/opt/stack/new/screen-logs
LOGFILE=/opt/stack/new/devstacklog.txt
VERBOSE=True
FIXED_RANGE=fixed_range
IPV4_ADDRS_SAFE_TO_USE=ip_safe_to_use
FLOATING_RANGE=floating_range
PUBLIC_NETWORK_GATEWAY=public_gateway
FIXED_NETWORK_SIZE=4096
VIRT_DRIVER=libvirt
SWIFT_REPLICAS=1
SWIFT_START_ALL_SERVICES=False
LOG_COLOR=False
UNDO_REQUIREMENTS=False
CINDER_PERIODIC_INTERVAL=10
export OS_NO_CACHE=True
LIBS_FROM_GIT=
EBTABLES_RACE_FIX=True
DEBUG_LIBVIRT_COREDUMPS=True
CINDER_VOLUME_CLEAR=none
LIBVIRT_TYPE=qemu
VOLUME_BACKING_FILE_SIZE=24G
TEMPEST_HTTP_IMAGE=http://git.openstack.org/static/openstack.png
FORCE_CONFIG_DRIVE=False
INSTALL_TESTONLY_PACKAGES=True
SUBNETPOOL_PREFIX_V4=subnetpool
ENABLED_SERVICES+=,placement-client,nova-api,neutron
What should I do to start the neutron?