KVM (Kernel-based Virtual Machine) is an open-source hypervisor for Linux that allows multiple virtual machines to run on a single physical machine. One of the key features of KVM is its ability to provide network connectivity to virtual machines using different networking models, including bridge networking.
In this article, we will discuss further how to configure bridge networking for KVM on Linux. We will start by briefly explaining the concept of bridge networking and its benefits, then We will walk through the steps required to configure bridge networking for KVM in Linux.
What is a Virtual Network Bridge?
Bridge networking is a method of connecting virtual machines to the external network by creating a virtual bridge between the physical network interface card (NIC) and the virtual network interface card (VNIC) of the virtual machine.
The virtual bridge acts as a switch that connects multiple VNICs to the physical NIC of the host machine. This allows virtual machines to communicate with other virtual machines in the same KVM network setup and the external network as if they were directly connected to the physical network.
Why Would You Need to Configure Bridge Networking for KVM in Linux?
You Need to Configure Bridge Networking for:
Improved Network Performance
Bridge networking allows virtual machines to use the same physical NIC as the host machine, which provides better network performance than other networking models such as NAT and host-only.
Simplified Network Configuration
Bridge networking eliminates the need for complex network configurations and allows virtual machines to obtain IP addresses from the same DHCP server as the host machine.
Flexible Network Topology
Bridge networking provides a flexible network topology that allows virtual machines to communicate with each other and the external network without restrictions.
Bridge networking isolates virtual machines from each other and the external network, which enhances security by preventing unauthorized access to sensitive data.
How do I Create a Bridge in Virtual Machine Manager?
step by step to Create a Bridge in Virtual Machine Manager in next lines:
Step 1: Create a Virtual Network
The first step in creating a bridge is to create a virtual network in the VMM. This can be done by navigating to the Virtual Switch Manager in the VMM console and selecting “New Virtual Network.” Choose a name for the network and select the appropriate connection type (e.g. external, internal, or private).
Step 2: Configure the Virtual Network Adapter
Once the virtual network has been created, the next step is to configure the virtual network adapter for each VM that will be connected to the bridge. This can be done by selecting the VM in the VMM console and choosing “Settings” > “Hardware Configuration” > “Network Adapter.” From here, select the virtual network from the drop-down menu and configure any other settings as needed (such as MAC address assignment or VLAN tagging).
Step 3: Create the Bridge
With the virtual network and adapters configured, the final step is to create the bridge itself. This can be done by selecting “Virtual Switch Manager” in the VMM console and choosing “New Virtual Switch.” Select “External” as the connection type and choose the physical network adapter that will be used to connect the bridge to the physical network.
Once the bridge has been created, it should automatically connect to any virtual networks that have been configured to use it. VMs that are connected to these virtual networks should now be able to communicate with each other and the host machine through the bridge.
KVM Network Bridge Vs Passthrough
KVM network bridge is a software-based solution that creates a virtual switch. The virtual switch connects the virtual machines to the physical network by using the host’s network interface card (NIC). The KVM network bridge acts as an intermediary between the virtual machines and the physical network, allowing them to communicate with each other and with the outside world.
KVM network passthrough, on the other hand, is a hardware-based solution that allows virtual machines to access the physical NIC directly. With passthrough, the virtual machine has direct access to the physical NIC, bypassing the host’s network stack entirely. This provides better performance and reduces the overhead associated with the virtual switch.
The main advantage of the KVM network bridge is that it is easy to set up and manage. It does not require any specialized hardware, and it can be configured from within the virtual machine manager. In addition, the KVM network bridge provides a layer of isolation between the virtual machines and the physical network, enhancing security.
However, Linux KVM network bridges may suffer from performance issues, especially when running high-bandwidth applications. The virtual switch can introduce latency and reduce network throughput, affecting the performance of the virtual machines.
Passthrough, on the other hand, offers superior performance and reduced latency. By allowing the virtual machine to access the physical NIC directly, the virtual machine can achieve near-native network performance.
However, Passthrough also has some disadvantages. It requires specialized hardware, such as Intel VT-d or AMD-Vi, to work properly. This means that not all hardware is compatible with passthrough, and it may require additional configuration to enable.
What is the Difference Between a Switch and a Bridge?
Switch and bridge are two networking devices that are used to connect multiple devices in a network. The main difference between them is the way they handle the data packets.
- A switch is a networking device that usually operates at the data link layer of the OSI model.
- It uses MAC addresses to identify and forward data packets between different devices on a network.
- Switches are designed to increase network performance and reduce network congestion by creating dedicated communication channels between devices.
- Switches can be managed or unmanaged, with managed switches offering more advanced features such as VLANs, QoS, and link aggregation.
- A bridge is also a networking device that operates at the data link layer of the OSI model.
- It uses MAC addresses to identify and forward data packets between different segments of a network.
- Bridges are typically used to connect two or more local area networks (LANs) together.
- Bridges were popular in the past but have largely been replaced by switches, which offer better performance and more advanced features.
In summary, switches are designed for local networks and use MAC addresses to forward data packets between devices, while bridges are used to connect different LANs together using MAC addresses to forward data packets between them.
What is the Difference Between KVM, VEPA and Bridge?
In conclusion, KVM, VEPA (Virtual Ethernet Port Aggregator), and Bridge are three different technologies used in virtualization and networking. KVM enables multiple virtual machines to run on a host system simultaneously, while VEPA and Bridge are used to connect different network segments together.
VEPA improves the performance of the virtual network by offloading some of the switching functions to the physical switch, while Bridge does not. Understanding the differences between these technologies can help you choose the right one for your use case.
In Conclusion, knowing how to configure bridge networking for KVM in Linux is very important for your business. Contact our 24/7 support team now at HostSailor to get personalized assistance.