Create VMs with KVM on Oracle Linux

Introduction

Kernel-based Virtual Machine (KVM) is an open-source type-1 (bare-metal) hypervisor. This functionality permits a host system, such as Oracle Linux, to host multiple virtual machines (VMs) or guests when running on supported hardware.

This tutorial will deploy Oracle Linux Kernel Virtualization Manager (KVM) to create a virtual machine.

Objectives

Deploy KVM
Deploy Cockpit for Virtual Machines
Create Virtual Machine from an ISO
Create Virtual Machine using Oracle Cloud Images

Prerequisites

Any Oracle Linux system with the following configurations:

a non-root user with sudo permissions

Deploy Oracle Linux

Note: If running in your own tenancy, read the linux-virt-labs GitHub project README.md and complete the prerequisites before deploying the lab environment.

Open a terminal on the Luna Desktop.

Clone the linux-virt-labs GitHub project.

git clone https://github.com/oracle-devrel/linux-virt-labs.git

Change into the working directory.
```
cd linux-virt-labs/ol
```

Install the required collections.

ansible-galaxy collection install -r requirements.yml

Deploy the lab environment.
```
ansible-playbook create_instance.yml -e localhost_python_interpreter="/usr/bin/python3.6" -e instance_ocpus="4" -e instance_memory="64"
```
The free lab environment requires the extra variable local_python_interpreter, which sets ansible_python_interpreter for plays running on localhost. This variable is needed because the environment installs the RPM package for the Oracle Cloud Infrastructure SDK for Python, located under the python3.6 modules.
The default deployment shape uses the AMD CPU and Oracle Linux 8. To use an Intel CPU or Oracle Linux 9, add -e instance_shape="VM.Standard3.Flex" or -e os_version="9" to the deployment command.
Important: Wait for the playbook to run successfully and reach the pause task. At this stage of the playbook, the installation of Oracle Linux is complete, and the instances are ready. Take note of the previous play, which prints the public and private IP addresses of the nodes it deploys and any other deployment information needed while running the lab.

Validate Environment Supports Virtualization

Open a terminal and connect via SSH to the ol-node-01 instance.
```
ssh oracle@<ip_address_of_instance>
```
Run the following command to determine your CPU type.
```
grep -e 'vendor_id' /proc/cpuinfo | uniq
```
The vendor_id reports either AuthenticAMD for an AMD CPU or GenuinIntel for an Intel CPU.
Check if the hardware supports virtualization.
Run the command that matches your CPU type.
1. Verify the AMD V CPU extensions exist.
```
grep -w -o 'svm' /proc/cpuinfo | uniq
```
1. Verify the Intel VT CPU extensions exist.
```
grep -w -o 'vmx' /proc/cpuinfo | uniq
```
The existence of one of these flags in the command output indicates this system supports virtualization. You can also use the lscpu command and look for the Virtualization entry in the output.
Check for the loaded KVM modules.
```
lsmod | grep kvm
```
The output displays the KVM kernel module and, depending on the system's hardware, either the kvm_amd or kvm_intel processor module. On modern Linux systems, these modules should load by default.

Install and Start KVM

Check the running version of Oracle Linux.
```
hostnamectl | grep 'Operating System'
```
Install the associated software packages for Oracle Linux virtualization.
Run the command based on your installed operating system.
Oracle Linux 8:
```
sudo dnf module install -y virt
```
Oracle Linux 9:
```
sudo dnf install -y qemu-kvm libvirt
```
These commands install the virtualization packages, which include libvirt, qemu-kvm, and other dependencies on Oracle Linux.

Install virt-install and virt-viewer.

sudo dnf install -y virt-install virt-viewer

Install these packages to enable https protocol support for an image installation souce.
Oracle Linux 8:
This functionality is available by default in this version of Oracle Linux.
Oracle Linux 9:
```
sudo dnf install -y qemu-kvm-block-curl
```
Validate the host machine is ready and set up to run libvirt VMs.
```
virt-host-validate
```
If all checks pass, the system is prepared for creating VMs. If any checks fail, follow the instructions to correct the problem. If any check returns the value of WARN, consider following the instructions to improve the virtualization capabilities.
In Oracle Linux 9, there is a WARN message regarding the cgroup devices controller support. This is expected based on an upstream issue that states, With cgroups v2 there is no devices controller; eBPF should be used instead.

Start the Systemd services and sockets, enabling them to start automatically on each boot. Then, check their status to confirm they are up and running.

Oracle Linux 8:

sudo systemctl enable --now libvirtd.service
sudo systemctl status libvirtd.service

Oracle Linux 9:

for drv in qemu network nodedev nwfilter secret storage interface
do 
   sudo systemctl start virt${drv}d{,-ro,-admin}.socket
done

for drv in qemu network nodedev nwfilter secret storage interface
do 
   sudo systemctl status virt${drv}d{,-ro,-admin}.socket
done

Output shows the service or sockets as enabled and running.

Setup Cockpit Web Console to manage KVM on Oracle Linux

Install the cockpit-machines extension for managing VMs based on Libvirt.
```
sudo dnf install -y cockpit cockpit-machines
```

Start the cockpit socket and enable it to auto-start on system boot.

sudo systemctl enable --now cockpit.socket
sudo systemctl status cockpit.socket

Example Output:

[oracle@ol-node01 ~]$ sudo systemctl enable --now cockpit.socket
Created symlink /etc/systemd/system/sockets.target.wants/cockpit.socket -> /usr/lib/systemd/system/cockpit.socket.
[oracle@ol-node01 ~]$ sudo systemctl status cockpit.socket
* cockpit.socket - Cockpit Web Service Socket
   Loaded: loaded (/usr/lib/systemd/system/cockpit.socket; enabled; vendor pres>
   Active: active (listening) since Mon 2022-06-13 21:39:24 GMT; 10s ago
     Docs: man:cockpit-ws(8)
   Listen: [::]:9090 (Stream)
...

Output indicates the service is enabled and listening.

Open another terminal on the Luna Desktop and enter the following command to create a local port forward for the Cockpit web console using SSH.
```
ssh -L 9090:localhost:9090 oracle@<ip_address_of_instance>
```
Open a web browser and enter the URL.
```
https://localhost:9090
```
The Cockpit web console uses a self-signed certificate to enable HTTPS. Approve the security warning based on the browser used. For Chrome, click the Advanced button and then the Proceed to localhost (unsafe) link.
Log in as the oracle user with the password of oracle.
The Cockpit Dashboard is displayed.
Click the "Limited Access" button to gain Administrative privileges.
Close the Administrative access window.

Create Virtual Machine from an ISO

Click the "Virtual Machines" option in the navigation panel on the left.
Click the "Create VM" button.
Provide the following information in the Create new virtual machine dialog.
- Installation source: https://yum.oracle.com/ISOS/OracleLinux/OL8/u10/x86_64/OracleLinux-R8-U10-x86_64-dvd.iso
Oracle provides access to the Oracle Linux Installation Media from https://yum.oracle.com/oracle-linux-isos.html . The disk size of 10 GiB and memory of 1 GiB are just for this tutorial and are not recommended for real-world use.
Click "Create and run" to begin.
From the list of Virtual Machines, click the ol-demo link.
Scroll down to view the VNC Console.
If you're quick enough, you will see a menu with the options to Install Oracle Linux or Test this media and Install. The Test option will be selected by default after a few seconds. The installer will validate that the content on the media is good and then start the installer.
Once the installer boots, you are presented with the Welcome to Oracle Linux screen. You begin the installation by selecting your language for the installation process.
This lab does not continue with the installation process.
Note: Check out these free videos demonstrating the Oracle Linux 8 and Oracle Linux 9 installation process.
Close the web browser by clicking the 'X' in the window's top-right corner.

Create a Virtual Machine using Oracle Cloud Images

Switch to the terminal running your KVM server.
Change to the KVM image storage location.
```
cd /var/lib/libvirt/images
```

Download the Oracle Linux VM template.

sudo curl -O https://yum.oracle.com/templates/OracleLinux/OL8/u10/x86_64/OL8U10_x86_64-kvm-b237.qcow2

Create a meta-data file.

cat << 'EOF' | sudo tee ~/meta-data > /dev/null
instance-id: iid-local01
local-hostname: vm-01
EOF

Create a user-data file.

cat << 'EOF' | sudo tee ~/user-data > /dev/null
#cloud-config

system_info:
  default_user:
    name: opc

ssh_authorized_keys:
  - <paste_public_key_here>
EOF

Generate an SSH Key Pair
```
ssh-keygen -t rsa -b 4096
```
Hit Enter to accept each of the defaults. The command writes the key pair to the .ssh directory in the user's home.

Copy the public key into the user-data file.

SSHKEY=$(cat ~/.ssh/id_rsa.pub)
sed -i "s|<paste_public_key_here>|${SSHKEY}|g" ~/user-data

Generate the ISO image.

sudo genisoimage -output /var/lib/libvirt/images/vm-01.iso -volid cidata -joliet -rock ~/user-data ~/meta-data

Find the OS variant that matches your image best.
Oracle Linux 8:
```
osinfo-query os | grep ol8
```
Oracle Linux 9:
```
virt-install --os-variant list | grep ol8
```

Create the instance.

Oracle Linux 8:

sudo cp /var/lib/libvirt/images/OL8U10_x86_64-kvm-b237.qcow2 /var/lib/libvirt/images/vm-01.qcow

sudo virt-install --name vm-01 \
--memory 2048 \
--vcpus 2 \
--disk /var/lib/libvirt/images/vm-01.qcow,device=disk,bus=virtio \
--disk /var/lib/libvirt/images/vm-01.iso,device=cdrom \
--os-type linux --os-variant ol8.10 \
--virt-type kvm --graphics none \
--network network=default,model=virtio \
--noautoconsole \
--import

Oracle Linux 9:

The --os-type option is deprecated and no longer required to create a virtual machine when running virt-install.

sudo cp /var/lib/libvirt/images/OL8U10_x86_64-kvm-b237.qcow2 /var/lib/libvirt/images/vm-01.qcow

sudo virt-install --name vm-01 \
--memory 2048 \
--vcpus 2 \
--disk /var/lib/libvirt/images/vm-01.qcow,device=disk,bus=virtio \
--disk /var/lib/libvirt/images/vm-01.iso,device=cdrom \
--os-variant ol8.10 \
--virt-type kvm --graphics none \
--network network=default,model=virtio \
--noautoconsole \
--import

List the VMs.
```
sudo virsh list
```
Retrieve the IP address of the vm-01 virtual machine.
```
sudo virsh net-dhcp-leases --network default
```
Note: Depending on how quickly the virtual machine starts, you may need to rerun the command to display the IP address.
Alternatively, you can filter based on the MAC address.
```
sudo virsh domiflist vm-01
```
Copy the MAC address from the previous output and provide it in the following command.
```
sudo virsh net-dhcp-leases --network default --mac <MAC_address>
```

Verify the virtual machine works by connecting with ssh.

ssh opc@<ip_address_of_vm-01>

You can verify the version and get additional details about the OS within the virtual machine by running hostnamectl.