Unable to get vnc console for instance

I installed nova using devstack . when i launch an instance, it gets an ip and show the "Build".
I am not able to get vnc console and view log.

In my system panel nothing had changed (0 used , 4 avail cores)

here is my config
--verbose
--nodaemon
--allow_admin_api
--scheduler_driver=nova.scheduler.simple.SimpleScheduler
--dhcpbridge_flagfile=/opt/stack/nova/bin/nova.conf
--network_manager=nova.network.manager.FlatDHCPManager
--fixed_range=172.16.0.0/12
--my_ip=192.168.21.172
--public_interface=eth0
--vlan_interface=eth0
--sql_connection=mysql://root:asd@localhost/nova
--libvirt_type=kvm
--osapi_extensions_path=/opt/stack/openstackx/extensions
--vncproxy_url=http://192.168.21.172:6080
--vncproxy_wwwroot=/opt/stack/noVNC/
--api_paste_config=/opt/stack/nova/bin/nova-api-paste.ini
--image_service=nova.image.glance.GlanceImageService
--ec2_dmz_host=192.168.21.172
--rabbit_host=localhost
--rabbit_password=asd
--glance_api_servers=192.168.21.172:9292
--multi_host=0
--send_arp_for_ha=1
--flat_network_bridge=br100
--flat_interface=eth0