Lab 05: Snapshots And Restore

Create a stopped-VM snapshot, change the VM, then restore the clean baseline.

You will learn:

• why snapshots require stopped VMs
• how yeast snapshot creates a reset point
• how yeast snapshots lists reset points
• how yeast restore replaces the current disk state
• why restore is intentionally explicit

What You Will Build

yeast-lab-05/
└── web VM
    ├── baseline snapshot
    ├── changed guest disk
    └── restored clean disk

Before You Start

Run:

yeast doctor

Step 1: Create And Start

mkdir yeast-lab-05
cd yeast-lab-05
yeast init --template ubuntu-basic
yeast up

Step 2: Create A Baseline

Snapshots require the VM to be stopped.

yeast down
yeast snapshot web baseline --description "Clean baseline"
yeast snapshots web

Expected result:

• a snapshot named baseline
• metadata showing the snapshot belongs to web

Step 3: Change The VM

yeast up
yeast exec web -- touch /home/yeast/marker
yeast exec web -- test -e /home/yeast/marker

The marker file proves the guest disk has changed after the baseline.

Step 4: Restore The Baseline

yeast down
yeast restore web baseline
yeast up
yeast exec web -- test ! -e /home/yeast/marker

If the last command succeeds, restore worked.

Warning

Restore replaces the current instance disk with the snapshot disk. Any changes made after the snapshot are removed.

Step 5: Delete The Snapshot

yeast down
yeast delete-snapshot web baseline
yeast snapshots web

Use this when you no longer need a reset point.

Clean Up

yeast destroy

What You Learned

Snapshots are per-instance reset points. They are safest when the VM is stopped because the disk is not changing underneath Yeast.

Next Lab

Continue with Multi-VM Private Networking.