Today we are going to learn that how to configure Open vSwitch on CentOS/RHEL. In our previous lecture you’ve learned that how to install Open vSwitch on CentOS/RHEL. If you missed the previous article simply click the below link to read it first for the installation of Open vSwitch on CentOS/RHEL.
How To Install Open vSwitch on CentOS 8 | RHEL 8
Here we’ll use the os-net-confi script for the configuration of Open vSwtich on CentOS/RHEL. So, follow the below steps to configure the Open vSwitch on your system.
Step 1: Install os-net-config Tool
To configure the Open vSwitch we need os-net-config tool as it will help us to perform configuration steps more easily. It provides the configuration of host networking using YAML or JSON files format.
By default, os-net-config use the YAML file that can be located under /etc/os-net-config/config.yaml. You can also customize this by –config-file(-c) CLI option.
Installing os-net-config by using OpenStack Repository
Hit the following command to install the os-net-config tool using OpenStack repository if you’ve already configured it.
sudo yum install os-net-config
Find out more details about the package by typing
[sabi@localhost ~]$ rpm -qi os-net-config Name : os-net-config Version : 11.3.1 Release : 1.el8 Architecture: noarch Install Date: Sat 08 Aug 2020 02:20:02 AM EDT Group : Unspecified Size : 3760703 License : ASL 2.0 Signature : RSA/SHA1, Sun 19 Apr 2020 12:34:05 PM EDT, Key ID f9b9fee7764429e6 Source RPM : os-net-config-11.3.1-1.el8.src.rpm Build Date : Fri 28 Feb 2020 08:55:33 AM EST Build Host : c1be.rdu2.centos.org Relocations : (not relocatable) Packager : CBS [email protected] Vendor : CentOS URL : http://pypi.python.org/pypi/os-net-config Summary : Host network configuration tool Description : Host network configuration tool for OpenStack.
Installing os-net-config with the help of Pip
You can also install the os-net-config tool using pip or pip3 as it is distributed as python package.
CentOS 8:
sudo dnf install python3-pip
CentOS 7:
sudo yum install -y epel-release
sudo yum -y install python-pip
sudo pip install os-net-config
Make sure to verify the PATH once the installation finished.
[sabi@localhost ~]$ which os-net-config /usr/bin/os-net-config
Step 2: Configuring Open vSwitch by using os-net-config
Let’s dive into the configuration of Open vSwitch by using os-net-config tool as we’ve already installed the Open vSwitch and the configuration tool.
Here we’ll see some example to understand that how we can configure.
Single Interface Configuration with Static IP Address
First create a YAML file to save configuration.
sudo nano ovs-interface.yml
And then configure as shown below:
network_config: - type: interface name: eth1 use_dhcp: false use_dhcpv6: false addresses: - ip_netmask: 172.11.101.10/24 routes: - ip_netmask: 0.0.0.0/0 next_hop: 172.11.101.254 default: true
Result:
It’ll configure the eth1 interface along with the static IP address as 172.11.101/24 and the gateway is 172.11.101.254.
Run the given command to apply the configuration changes.
sudo os-net-config -c ovs-interface.yml
Configure OVS bridge With Single Attached Interface (Port)
First create the file for configuration and then do the changes as given below:
sudo nano ovs-bridge-single-interface.yml
It’ll look like this:
network_config: - type: ovs_bridge name: br-ex use_dhcp: false use_dhcpv6: false addresses: - ip_netmask: 172.11.101.10/24 routes: - ip_netmask: 0.0.0.0/0 next_hop: 172.11.101.254 default: true members: - type: interface name: eth1
Finally apply the configuration.
os-net-config -c ovs-bridge-single-interface.yml
Configure OVS Bridge on OVS Bond
Follow the below configuration for OVS bridge.
network_config: - type: ovs_bridge name: br-ex use_dhcp: true members: - type: ovs_bond name: bond1 members: - type: interface name: em1 - type: interface name: em2
Apply the changes in a file as done in above step.
Configure Tagged VLAN Interface On Top of OVS Bridge
Here’s the configuration sample.
network_config: - type: ovs_bridge name: br-ctlplane use_dhcp: true members: - type: interface name: em1 - type: vlan vlan_id: 20 addresses: - ip_netmask: 192.0.2.1/24
Creating an OVS Bond
You can create OVS bond by doing the changes as given below:
network_config: - type: ovs_bridge name: bond1 use_dhcp: true members: - type: interface name: eno1 - type: interface name: eno2
Checking OVS Configuration
Once the settings are applied, network config script will be added automatically to /etc/sysconfig/network-scripts/ directory.
ls /etc/sysconfig/network-scripts/
Verify the settings by hitting
ovs-vsctl show
Step 3: Creating KVM Network with OVS
For users who are using Open vSwitch with KVM virutalization, need to define the network that Virtual Machine will use.
Create xml config file.
sudo nano kvm-ovs.xml
Then add the bridge details in the file and save it.
<network> <name>ovs-bridge </name> <forward mode='bridge'/> <bridge name='br-ex'/> <virtualport type='openvswitch'/> <network/>
Note:
ovs-bridge: Name of the libvirt network
br-ex: Name of OVS bridge
To define a network from the XML file, without starting it hit
sudo virsh net-define kvm-ovs.xml
If you want to start the inactive network(previously defined) type
sudo virsh net-start ovs-bridge
To start a network when service started, type the following command:
sudo virsh net-autostart ovs-bridge
Verify that autostart flag is turned to yes.
sudo virsh net-list --all
So, this is how you can configure the Open vSwitch on CentOS/RHEL.
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