IT 3300 : Virtualization

Proxmox — LXC Containers

LXC vs. VM

• A VM boots its own kernel — full isolation, more overhead
• An LXC container shares the host kernel — lighter, faster, denser
• Same idea as Docker, but LXC is a system container (a whole OS
  userland), not a single-app container

LXC vs. Docker

• LXC — behaves like a lightweight Linux machine; you SSH in, run services
• Docker — packages one application and its dependencies to run anywhere
• Proxmox uses LXC; we'll use Docker later for app packaging

Creating an LXC container

• Download a template (Datacenter -> storage -> CT Templates)
• Click Create CT
• Set hostname, password/SSH key, disk, CPU, memory, network
• Starts in seconds

When to use LXC

• Lightweight Linux services where a full VM is overkill
• High density on a single node
• You control the workload and are fine sharing the host kernel

When to use a VM instead

• You need a different kernel or OS (e.g. Windows)
• Strong isolation for untrusted or security-sensitive workloads
• You'll run Docker/Kubernetes inside it (nesting is cleaner in a VM)

Lab goals

• Create one LXC container from a template
• Compare its boot time and memory use to your VM
• Note which you'd choose for a small web service, and why