How to Run a Linux VM Using `bhyve` on FreeBSD Operating System

Introduction

FreeBSD is a powerful and versatile operating system known for its robustness, performance, and advanced features. One of its standout features is the bhyve hypervisor, which allows users to run virtual machines (VMs) on FreeBSD. bhyve (pronounced “bee-hive”) is a type-2 hypervisor that provides a lightweight and efficient way to virtualize various operating systems, including Linux, Windows, and other BSD variants.

In this article, we will explore how to run a Linux VM using bhyve on a FreeBSD system. We will cover the necessary steps, from setting up bhyve to configuring and running a Linux VM. By the end of this guide, you should have a functional Linux VM running on your FreeBSD host.

Prerequisites

Before we dive into the process, ensure that you have the following prerequisites in place:

1. FreeBSD System: A working FreeBSD installation (version 10.0 or later is recommended, as bhyve was introduced in FreeBSD 10.0).
2. Root Access: Administrative privileges on the FreeBSD system.
3. Hardware Virtualization Support: Ensure that your CPU supports hardware virtualization (Intel VT-x or AMD-V). You can check this by running:

   grep -E 'VTx|AMD-V' /var/run/dmesg.boot
   

   If you see output related to VT-x or AMD-V, your CPU supports hardware virtualization.
4. Sufficient Resources: Ensure that your system has enough RAM, CPU cores, and disk space to allocate to the VM.

Step 1: Install bhyve and Related Tools

bhyve is included in the FreeBSD base system, but you may need to install additional tools to manage VMs effectively. The vm-bhyve package is a popular management tool that simplifies the process of creating and managing VMs.

1. Update the FreeBSD Package Repository:

   pkg update
   

2. Install vm-bhyve:

   pkg install vm-bhyve
   

3. Enable bhyve at Boot: Add the following lines to /etc/rc.conf to enable bhyve and vm-bhyve at boot:

   bhyve_enable="YES"
   vm_enable="YES"
   vm_dir="zfs:zroot/vm"
   

   Replace zroot/vm with the appropriate ZFS dataset or directory where you want to store your VMs.

4. Start the vm-bhyve Service:

   service vm start
   

Step 2: Configure Networking for bhyve

bhyve VMs require network connectivity, and you can configure this using a bridge interface. The bridge allows the VM to communicate with the host and the external network.

1. Create a Bridge Interface: Add the following lines to /etc/rc.conf to create a bridge interface:

   cloned_interfaces="bridge0"
   ifconfig_bridge0="addm em0 up"
   

   Replace em0 with the name of your physical network interface.

2. Restart Networking: Restart the networking service to apply the changes:

   service netif restart
   

3. Configure vm-bhyve Networking: Edit the vm-bhyve configuration file (/usr/local/etc/vm.conf) to use the bridge interface:

   switch_list="public"
   switch_public_interface="bridge0"
   

Step 3: Prepare the Linux ISO Image

To install a Linux distribution on the VM, you will need an ISO image of the Linux distribution you want to install. You can download the ISO from the official website of the Linux distribution.

1. Download the Linux ISO: For example, to download Ubuntu Server 20.04 LTS:

   fetch https://releases.ubuntu.com/20.04/ubuntu-20.04.3-live-server-amd64.iso
   

2. Store the ISO in the vm-bhyve ISO Directory: Move the downloaded ISO to the vm-bhyve ISO directory:

   mv ubuntu-20.04.3-live-server-amd64.iso /zroot/vm/.iso/
   

Step 4: Create and Configure the Linux VM

Now that the prerequisites are in place, you can create and configure the Linux VM using vm-bhyve.

1. Create the VM: Use the vm create command to create a new VM. For example, to create a VM named ubuntu-vm:

   vm create -t ubuntu -s 20G ubuntu-vm
   

   This command creates a VM with a 20GB disk. Adjust the size as needed.

2. Configure the VM: Edit the VM configuration file (/zroot/vm/ubuntu-vm/ubuntu-vm.conf) to specify the ISO image and other settings:

   loader="uefi"
   cpu=2
   memory=2G
   network0_type="virtio-net"
   network0_switch="public"
   disk0_type="virtio-blk"
   disk0_name="disk0.img"
   disk0_dev="sparse-zvol"
   uuid="..."
   network0_mac="..."
   

   Adjust the cpu, memory, and other settings according to your requirements.

3. Attach the ISO Image: Attach the Linux ISO image to the VM:

   vm iso ubuntu-vm /zroot/vm/.iso/ubuntu-20.04.3-live-server-amd64.iso
   

Step 5: Install Linux on the VM

With the VM configured, you can now start the VM and install Linux.

1. Start the VM: Start the VM using the vm start command:

   vm start ubuntu-vm
   

2. Connect to the VM Console: Connect to the VM console to interact with the Linux installer:

   vm console ubuntu-vm
   

3. Follow the Linux Installation Process: Follow the on-screen instructions to install Linux on the VM. This process is similar to installing Linux on a physical machine.

4. Reboot the VM: Once the installation is complete, reboot the VM:

   vm poweroff ubuntu-vm
   vm start ubuntu-vm
   

5. Detach the ISO Image: After the installation, detach the ISO image from the VM:

   vm iso -d ubuntu-vm
   

Step 6: Manage the Linux VM

With the Linux VM up and running, you can manage it using vm-bhyve commands.

1. Start and Stop the VM:

   • Start the VM:

     vm start ubuntu-vm
     

   • Stop the VM:

     vm poweroff ubuntu-vm
     

2. View VM Status: Check the status of the VM:

   vm list
   

3. Access the VM Console: Connect to the VM console:

   vm console ubuntu-vm
   

4. Modify VM Configuration: Edit the VM configuration file (/zroot/vm/ubuntu-vm/ubuntu-vm.conf) to change settings such as CPU, memory, or disk size.

5. Delete the VM: If you no longer need the VM, you can delete it:

   vm destroy ubuntu-vm
   

Conclusion

Running a Linux VM using bhyve on FreeBSD is a straightforward process that leverages the powerful virtualization capabilities of the FreeBSD operating system. By following the steps outlined in this guide, you can set up, configure, and manage a Linux VM with ease. Whether you’re testing software, running a development environment, or exploring different Linux distributions, bhyve provides a reliable and efficient platform for virtualization on FreeBSD.

With bhyve and vm-bhyve, FreeBSD users have access to a robust virtualization solution that is both lightweight and highly customizable. As you become more familiar with these tools, you can explore advanced features such as snapshots, cloning, and network configurations to further enhance your virtualization experience on FreeBSD.