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Deployment of Cloud / Virt ready OS Images

If you’re running this demo code on a cloud hosted environment then simply select their pre-configured cloud ready image, and skip to the setup of the demo tooling using Ansible.

Follow these instructions to run a local VM under KVM + Libvirt.

Validated Images

  • rhel-baseos-9.0-beta-0-x86_64-kvm.qcow2

  • rhel-8.5-x86_64-kvm.qcow2

  • Fedora-Cloud-Base-35-1.2.x86_64.qcow2

The process I’m using is I create a working snapshot off the working image and then customize the image to set a simple password for the root user. Ideally we should be using the cloud-init capabilities to inject a valid user and credentials, but this is a quick hack to speed up this demo deployment.

Deployment Customisation

You will need to update the following varibles to suit you local KVM environment

  • VM_BRIDGE to match the network you’re using

  • VM_BASE to the location of the base qcow image we’re working off

  • VM_IMAGE to the location you want to use for the working image.

The current process uses virt-customize to strip out cloud-init from the base image and set an initial password for the root user to password.

Deploy Fedora VM under KVM

VM_NAME=Fedora35
VM_MEMORY=2048
VM_CPU=2
OS_VARIANT=fedora34
VM_BRIDGE=virbr1

VM_BASE=/opt/Virtual/ISO/Fedora-Cloud-Base-35-1.2.x86_64.qcow2
VM_IMAGE=/opt/Virtual/images/Fedora-35.qcow2

# Create our working snapshot
qemu-img create -f qcow2 -F qcow2 \
-o backing_file=${VM_BASE} ${VM_IMAGE}

# Enable root password login and remove cloud-init
virt-customize -a ${VM_IMAGE} \
-root-password password:password --uninstall cloud-init \
--run-command 'echo PermitRootLogin yes >> /etc/ssh/sshd_config'

# Then Create the VM

virt-install --name ${VM_NAME} --memory ${VM_MEMORY} --vcpus ${VM_CPU} \
    --disk path=$VM_IMAGE,format=qcow2,bus=scsi,discard=unmap \
    --os-variant=${OS_VARIANT} \
    --controller=type=scsi,model=virtio-scsi \
    --connect qemu:///system \
    --virt-type kvm \
    --noautoconsole \
    --import \
    --network type=bridge,source=${VM_BRIDGE} --graphics vnc

virsh console ${VM_NAME}

Normally SSH as root is disabled by default in a Fedora Image, our virt-customize line re-adds this capability. If you’re working with a vanilla cloud image on AWS or Azure you might need to type the following via a remote console.

echo "PermitRootLogin yes" > /etc/ssh/sshd_config.d/01-permitrootlogin.conf
systemctl restart sshd

I also recommend adding an entry in ~/.ssh/config with the correct IP address for your VM which will simplify running the ansible playbook. If you’re using KVM you should see the IP address in the virsh console.

Host fedora35
Hostname 192.168.124.138
StrictHostKeyChecking no
UserKnownHostsFile /dev/null
User root

You should then enable login via your ssh-key so that Ansible can automate the rest of the setup

ssh-copy-id fedora35

Deploy a RHEL 8.5 VM under KVM

This is effectively the same as the Fedora version

VM_NAME=RHEL85
VM_MEMORY=2048
VM_CPU=2
OS_VARIANT=rhel8.5
VM_BRIDGE=virbr1

VM_BASE=/opt/Virtual/ISO/rhel-8.5-x86_64-kvm.qcow2
VM_IMAGE=/opt/Virtual/images/RHEL-85.qcow2

qemu-img create -f qcow2 -F qcow2 \
-o backing_file=${VM_BASE} ${VM_IMAGE}

virt-customize -a ${VM_IMAGE} \
-root-password password:password --uninstall cloud-init

# Then Create the VM

virt-install --name ${VM_NAME} --memory ${VM_MEMORY} --vcpus ${VM_CPU} \
    --disk path=$VM_IMAGE,format=qcow2,bus=scsi,discard=unmap \
    --os-variant=${OS_VARIANT} \
    --controller=type=scsi,model=virtio-scsi \
    --connect qemu:///system \
    --virt-type kvm \
    --noautoconsole \
    --import \
    --network type=bridge,source=${VM_BRIDGE} --graphics vnc

virsh console ${VM_NAME}

One big difference with RHEL 8.x is we don’t need to tweak the sshd_config.

I also recommend adding an entry in ~/.ssh/config with the correct IP address for your VM which will simplify running the ansible playbook.

Host rhel85
Hostname 192.168.124.160
StrictHostKeyChecking no
UserKnownHostsFile /dev/null
User root

You should then enable login via your ssh-key so that Ansible can automate the rest of the setup

ssh-copy-id rhel85

Environment Cleanup

Providing you’ve got the same shell open you can quickly clean up the deployed environment via

virsh destroy ${VM_NAME}
virsh undefine ${VM_NAME}
rm ${VM_IMAGE}