KVM/Libvirt VM Orchestration

🖧 Infrastructure Context

Access via SSH from the default terminal. The cluster topology is defined below:

📄 /etc/hosts (Cluster Inventory)


# Management & Controller
10.0.0.15   terminal       # Main Entry Point

# Web & Application Tier
10.0.0.60   web-srv1   # Nginx / Apache
10.0.0.70   app-srv1    # Backend App

# Data Persistence Tier
10.0.0.80   data-001    # Primary DB
10.0.0.90   data-002    # Replica / Backup

# Virtualization & Containers
10.0.0.100  kvm-001        # Libvirt Hypervisor
10.0.0.110  docker-001     # Container Runtime

⚠️

Constraint: Nested SSH is forbidden. Connect directly from terminal to target IPs.

📋 Engineering Requirements

Business Context: The QA team requests a dedicated, isolated compute instance on the kvm-001 hypervisor for integration testing. The environment must be provisioned using standard CLI tools to ensure reproducibility.

Technical Objectives:

Host Readiness: Validate the qemu-kvm and libvirtd stack status.
Storage: Provision a 10 GiB qcow2 volume (Thin Provisioned) named qa-vm-disk.qcow2.
Instance Definition (qa-vm01):
- Specs: 1 vCPU, 1024 MiB RAM.
- Network: Default NAT bridge.
- Console: Serial redirection (Headless mode).
Lifecycle: Enable auto-start on boot and perform a graceful shutdown test.

🔧 Implementation Procedure

Access Hypervisor Node

Connect to the virtualization host.
Ventana de terminal
```
ssh kvm-001
```
Verify Host Prerequisites

Ensure the libvirt daemon is active and enabled.
Ventana de terminal
```
sudo systemctl is-active libvirtd
# If inactive: sudo systemctl enable --now libvirtd
```
Provision Storage Volume

Create the virtual disk using qemu-img.
Ventana de terminal
```
sudo qemu-img create -f qcow2 /var/lib/libvirt/images/qa-vm-disk.qcow2 10G
```

Define and Boot Instance

Execute virt-install with parameters for a headless environment (--graphics none).

sudo virt-install \
  --name qa-vm01 \
  --ram 1024 \
  --vcpus 1 \
  --disk path=/var/lib/libvirt/images/qa-vm-disk.qcow2,format=qcow2 \
  --os-variant rocky9 \
  --network network=default \
  --graphics none \
  --console pty,target_type=serial \
  --location "https://download.rockylinux.org/pub/rocky/9/BaseOS/x86_64/os/" \
  --extra-args "console=ttyS0"

Tip: To detach from the console without killing the VM, press Ctrl + ].

Configure Autostart

Ensure the VM survives host reboots.
Ventana de terminal
```
sudo virsh autostart qa-vm01
```
Validate Lifecycle Control

Verify the VM is running, then request an ACPI shutdown.
Ventana de terminal
```
# Check status
sudo virsh list --all

# Graceful shutdown request
sudo virsh shutdown qa-vm01
```

🔍 Troubleshooting

“Guest name already in use”: If a previous attempt failed partially, clean up the metadata:
Ventana de terminal
```
sudo virsh destroy qa-vm01
sudo virsh undefine qa-vm01
```
Console Hanging: If the console does not show output, ensure --extra-args "console=ttyS0" was passed correctly to redirect kernel logs to the serial port.