upgrade planning

Practical Bash-first playbook for safe Linux upgrades on AI hosts: explains why GPU/driver/kernel coupling and container limits make stacks fragile, then shows how to inventory and freeze components, snapshot for rollback, stage changes in venvs/containers, upgrade in a controlled order, and validate with scripts; includes NVIDIA/ROCm tips, container runtime setup, rollback via Snapper/LVM/Timeshift, and an Ubuntu LTS example.