Steps to Configure Network on Openstack in CentOS 7 - Part 1

Q: How to Configure Network in OpenStack

Step 1:

Cheek interface using “ip a” command

ip a

Copy Interface file and edit

cd /etc/sysconfig/network-scripts/

cp ifcfg-enp0s3 ifcfg-br-ex

vi /etc/sysconfig/network-scripts/ifcfg-br-ex

TYPE=OVSBridge

BOOTPROTO=static

DEFROUTE=yes

PEERDNS=yes

PEERROUTES=yes

NAME=br-ex

UUID=d2f77013-76f1-4829-8137-d98f44a19632

DEVICE=br-ex

DEVICETYPE=ovs

ONBOOT=yes

IPADDR=172.17.20.100

NETMASK=255.255.0.0

GATEWAY=172.17.0.1

DNS1=8.8.8.8

vi /etc/sysconfig/network-scripts/ifcfg-enp3s0

TYPE="OVSPort"

DEVICETYPE="ovs"

OVS_BRIDGE="br-ex"

BOOTPROTO=static

DEFROUTE=yes

PEERDNS=yes

PEERROUTES=yes

NAME=enp3s0

UUID=d2f77013-76f1-4829-8137-d98f44a19632

DEVICE=enp3s0

ONBOOT=yes

Restart Network Service

systemctl restart network

Check Status :

ip a

Step 2:

Configure Neutron Controller: open File and add Below line

vi /etc/neutron/plugin.ini

type_drivers = vxlan,flat



flat_networks = *




Restart neutron-server Service

systemctl restart neutron-server.service

Step 3:

Map the Bridge to the physical network : Find bridge_mappings and add “physnet1:br-ex“

vi /etc/neutron/plugins/ml2/openvswitch_agent.ini

bridge_mappings = physnet1:br-ex



Restart the neutron-openvswitch-agent service

systemctl restart neutron-openvswitch-agent

Step 4:

Enables the use of External provider networks and leave blank

vi /etc/neutron/l3_agent.ini

external_network_bridge =




Restart neutron-l3-agent

systemctl restart neutron-l3-agent.service

Step 5:

Load source file : find in /root/ or create new one with following content

unset OS_SERVICE_TOKEN

export OS_USERNAME=admin

export OS_PASSWORD=server

export OS_AUTH_URL=http://172.17.20.100:5000/v2.0

export PS1='[\u@\h \W(keystone_admin)]\$ '

export OS_TENANT_NAME=admin

export OS_REGION_NAME=RegionOne




Run source file

source keystonerc_admin

Step 6:

Create Flat External Network Interface and Associate it with the configured physical_network

neutron net-create linuxtopic-external --provider:network_type flat --provider:physical_network physnet1 --router:external=True --shared

End of Part-1 ####


Part 1: OpenStack Mitaka 5 installation in CentOS 7

Part 2: Network Configuration in OpenStack

Part 3: Network & Router configuration using Dashboard

Part 4: Create Project, Image, Volume & Instance

Part 5: Instance Snapshot & Boot from Volume

Part 6: Autostart OpenStack Instance Setting

Part 7: Extend Volume Size