dhcp ip allocation issue

asked 2016-04-21 06:25:46 -0500

DarkKnight gravatar image

updated 2016-04-22 00:54:58 -0500

I have installed openstack Mitaka using packstack installation allinone setup on centos 7. I have used the below comands.

packstack --allinone --provision-demo=n --os-neutron-ovs-bridge-mappings=extnet:br-ex  --os-neutron-ml2-type-drivers=vxlan,flat

Next i created the nw scripts for the br-ex bridge following the exact steps mentioned here

Next i followed these commands

neutron net-create external_network --provider:network_type flat --provider:physical_network extnet  --router:external

 neutron subnet-create --name public_subnet --enable_dhcp=False --allocation-pool=start=,end= --gateway= external_network

Now when i launch instances , the instances are assigned IP in the 172.19.18.x series, as it reflects in the console. But when i login to the console of the created instance using the horizon vnc console, i am surprised to see the IP as something else.( When i see the /var/log/messages, i found out that this IP is taken from the DHCP server of my work-place.

I also checked to see if the dhcp server is actually running on my node and found out that only the dhcp-agent was running and not the dns-server

[root@set-compute ~(keystone_admin)]# ps -ef | grep dhcp
neutron   6925     1  0 Apr20 ?        00:03:04 /usr/bin/python2 /usr/bin/neutron-dhcp-agent --config-file /usr/share/neutron/neutron-dist.conf --config-file /etc/neutron/neutron.conf --config-file /etc/neutron/dhcp_agent.ini --config-dir /etc/neutron/conf.d/common --config-dir /etc/neutron/conf.d/neutron-dhcp-agent --log-file /var/log/neutron/dhcp-agent.log
root     47546 48045  0 22:19 pts/0    00:00:00 grep --color=auto dhcp

ps -ef | grep dnsmasq : gave no O/p.

Also i have noticed that even though i have an external network present, i dont see any network namespace being created. "ip netns list" - gives no o/p.

Also i am attaching the o/p of the various neutron configuration files.

[root@set-compute ~(keystone_admin)]# grep -v -e^# -e^$ /etc/neutron/dnsmasq-neutron.conf
[root@set-compute ~(keystone_admin)]# grep -v -e^# -e^$ /etc/neutron/dhcp_agent.ini
interface_driver = neutron.agent.linux.interface.OVSInterfaceDriver
resync_interval = 30
dhcp_driver = neutron.agent.linux.dhcp.Dnsmasq
enable_isolated_metadata = True
enable_metadata_network = False
dnsmasq_config_file =/etc/neutron/dnsmasq-neutron.conf
debug = False
root_helper=sudo neutron-rootwrap /etc/neutron/rootwrap.conf

/etc/neutron /neutron.conf file contents

[root@set-compute ~(keystone_admin)]# grep -v -e^# -e^$ /etc/neutron/neutron.conf
bind_host =
auth_strategy = keystone
core_plugin = neutron.plugins.ml2.plugin.Ml2Plugin
service_plugins =router,metering
allow_overlapping_ips = True
notify_nova_on_port_status_changes = True
notify_nova_on_port_data_changes = True
api_workers = 24
rpc_workers = 24
router_scheduler_driver = neutron.scheduler.l3_agent_scheduler.ChanceScheduler
l3_ha = False
debug = False
verbose = True
log_dir = /var/log/neutron
rpc_backend = rabbit
control_exchange = neutron
root_helper = sudo neutron-rootwrap /etc/neutron/rootwrap.conf
connection = mysql+pymysql://neutron:693c6bb5fb264b95@
auth_uri =
region_name = RegionOne
auth_type = password
project_name=services ...
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Update: Contents for my answers file:

Private interface for flat DHCP on the Compute servers.


Compute Network Manager. ['^nova.network.manager.\w+Manager$']

CONFIG_NOVA_NETWORK_MANAGER=nova.network.manager.FlatDHCPManager Any help ??

DarkKnight gravatar imageDarkKnight ( 2016-04-22 01:04:59 -0500 )edit

Hey! someone please help. Has none of you guys faced this issue. Any hints ??

DarkKnight gravatar imageDarkKnight ( 2016-04-27 01:02:16 -0500 )edit