Preemptible and Spot VMs in GCP - Step-by-Step Execution

Process Flow - Preemptible and Spot VMs

User requests VM

↓

Check VM type

↓

Preemptible?

↓

Create VM

↓

Run VM

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Google may stop VM anytime

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VM stopped or deleted

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User can restart or create new VM

When you request a VM as preemptible or spot, Google creates it but can stop it anytime to save resources. You can restart or create new VMs as needed.

Execution Sample

GCP

gcloud compute instances create example-vm \
  --zone=us-central1-a \
  --preemptible

This command creates a preemptible VM that runs until Google stops it, usually within 24 hours.

Process Table

Step	Action	VM State	Google's Decision	User Impact
1	User requests preemptible VM	VM not created	Check resource availability	Waiting for VM creation
2	Google creates VM	VM running	VM runs normally	User can use VM
3	Google needs resources	VM running	Decides to preempt VM	VM will be stopped soon
4	Google stops VM	VM stopped	VM preempted	User loses VM, must restart or create new
5	User restarts or creates new VM	VM running	VM runs normally	User continues work
6	VM runs up to 24 hours	VM running	VM may be preempted anytime	User should save work often
7	VM reaches max runtime	VM stopped	VM automatically stopped	User must restart or create new
8	End	VM stopped or running	No further action	User manages VM lifecycle

💡 VM stops when Google reclaims resources or max runtime reached; user must manage restarts.

Status Tracker

Variable	Start	After Step 2	After Step 4	After Step 5	After Step 7	Final
VM State	Not created	Running	Stopped	Running	Stopped	Stopped or Running
Google Decision	None	Run VM	Preempt VM	Run VM	Stop VM	No action
User Impact	Waiting	Using VM	VM lost	Using VM	Must restart	Manage VM

Key Moments - 3 Insights

Why does the VM stop even if I did not ask it to?

Google can stop preemptible or spot VMs anytime to free resources, as shown in execution_table step 4 where Google preempts the VM.

Can I keep a preemptible VM running forever?

No, preemptible VMs have a max runtime (usually 24 hours) after which Google stops them automatically (see step 7).

What should I do when my preemptible VM stops?

You need to restart or create a new VM to continue work, as shown in step 5 where the user restarts the VM.

Visual Quiz - 3 Questions

Look at the execution_table at step 4, what is the VM state?

A Running

B Stopped

C Not created

D Restarting

💡 Hint

Check the 'VM State' column in row for step 4 in execution_table.

At which step does the user restart or create a new VM?

A Step 3

B Step 7

C Step 5

D Step 2

💡 Hint

Look for 'User restarts or creates new VM' in the 'Action' column.

If Google never needed resources, what would happen to the VM state in the table?

A VM would keep running until max runtime

B VM would stop at step 4

C VM would never be created

D VM would restart automatically

💡 Hint

Refer to step 6 and 7 about VM running and max runtime.

Concept Snapshot

Preemptible and Spot VMs are cheaper VMs that Google can stop anytime.
You create them like normal VMs but expect interruptions.
Google stops them to free resources or after max runtime (~24h).
You must save work often and be ready to restart or create new VMs.
Ideal for batch jobs or fault-tolerant workloads.

Full Transcript

When you create a preemptible or spot VM on Google Cloud, the VM runs normally but can be stopped by Google at any time to free resources. This stopping is called preemption. The VM can run up to about 24 hours before Google stops it automatically. When the VM stops, you lose it and must restart or create a new one to continue your work. This makes preemptible and spot VMs cheaper but less reliable. They are good for tasks that can handle interruptions. The execution table shows the VM state changes from creation, running, preemption, stopping, and restarting. The variable tracker shows how VM state, Google's decisions, and user impact change step by step. Key moments clarify why VMs stop unexpectedly and what users should do. The quiz tests understanding of VM states and lifecycle steps. Remember, always save your work often and plan for VM interruptions when using preemptible or spot VMs.