CentOS 7 Tips

Post-Tasks to Minimal Install

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Remove virbr0 network interface

Case 1: Not using libvirtd service and virbr0 interface

# Stop and Disable the service
systemctl stop libvirtd.service
systemctl disable libvirtd.service

# RemoveReboot the host to remove the virbr0 interface
systemctl reboot

Case 2: Using libvirtd and dont want "virbr0"

# List the default network set-up for the virtual machines
virsh net-list

Name       State    Autostart    Persistent
----------------------------------------------------------
default    active   yes          yes

# Destroy the network default.
virsh net-destroy default

Network default destroyed

# Permanently remove the default vitual network from the configuration.
virsh net-undefine default

Network default has been undefined

# The interface virbr0 is now gone. You can verify it in the ifconfig or ip command output.
ifconfig virbr0

virbr0: error fetching interface information: Device not found

Case 3: Removing virbr0 interface on running machines ( non-persistence across reboots )

# First, list out the virtual bridge interfaces available on the system using the below command.
brctl show

bridge name     bridge id               STP enabled     interfaces
virbr0          8000.5254003008b6       yes             virbr0-nic

# Make the bridge interface down before removal.
ip link set virbr0 down

# Now, remove the bridge
brctl delbr virbr0

# check if the bridge is removed
brctl show

bridge name     bridge id               STP enabled     interfaces

Removing lxcbr0 interface

# change the below line in /etc/sysconfig/lxc. This will be effective after reboot. change the line from

USE_LXC_BRIDGE="true"
# to
USE_LXC_BRIDGE="false"

# remove the lxcbr0 bridge interface for the running system
brctl show
ip link set virbr0lxcbr0 down
brctl delbr virbr0lxcbr0
# Verify that the bridge has been removed.
brtclbrctl show