Compute commands (instances, disks) in GCP - Commands & Configuration

Introduction

Creating and managing virtual machines and their storage disks in the cloud can be confusing. These commands help you start, check, and stop virtual machines and their disks easily on Google Cloud Platform.

When you want to create a new virtual machine to run your application.

When you need to attach extra storage to your virtual machine.

When you want to check the status of your virtual machines and disks.

When you want to stop a virtual machine to save costs.

When you want to delete a disk that is no longer needed.

Commands

This command creates a new virtual machine named 'example-instance' in the 'us-central1-a' zone with a medium machine type and Debian 11 operating system.

Terminal

gcloud compute instances create example-instance --zone=us-central1-a --machine-type=e2-medium --image-family=debian-11 --image-project=debian-cloud

Expected Output

Created [https://www.googleapis.com/compute/v1/projects/my-project/zones/us-central1-a/instances/example-instance].

NAME               ZONE           MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP     STATUS

example-instance    us-central1-a  e2-medium                 10.128.0.2   34.68.123.45    RUNNING

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--zone - Specifies the zone where the instance will be created.

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--machine-type - Defines the hardware resources for the instance.

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--image-family - Selects the OS image family for the instance.

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--image-project - Specifies the project that contains the OS image.

This command creates a new persistent disk named 'example-disk' with 50GB size in the same zone as the instance.

Terminal

gcloud compute disks create example-disk --size=50GB --zone=us-central1-a

Expected Output

Created [https://www.googleapis.com/compute/v1/projects/my-project/zones/us-central1-a/disks/example-disk].

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--size - Sets the size of the disk.

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--zone - Specifies the zone where the disk will be created.

This command attaches the previously created disk 'example-disk' to the virtual machine 'example-instance'.

Terminal

gcloud compute instances attach-disk example-instance --disk=example-disk --zone=us-central1-a

Expected Output

Attached disk [example-disk] to instance [example-instance].

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--disk - Specifies the disk to attach.

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--zone - Specifies the zone of the instance.

This command lists all virtual machines in the 'us-central1-a' zone to check their status and details.

Terminal

gcloud compute instances list --zones=us-central1-a

Expected Output

NAME               ZONE           MACHINE_TYPE  PREEMPTIBLE  INTERNAL_IP  EXTERNAL_IP     STATUS

example-instance    us-central1-a  e2-medium                 10.128.0.2   34.68.123.45    RUNNING

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--zones - Filters the list to a specific zone.

This command stops the virtual machine 'example-instance' to save costs when it is not needed.

Terminal

gcloud compute instances stop example-instance --zone=us-central1-a

Expected Output

Stopped [https://www.googleapis.com/compute/v1/projects/my-project/zones/us-central1-a/instances/example-instance].

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--zone - Specifies the zone of the instance to stop.

Key Concept

If you remember nothing else from this pattern, remember: use gcloud commands with the right zone and resource names to create, manage, and check your virtual machines and disks.

Common Mistakes

Not specifying the zone when creating or managing instances and disks.

The command fails or affects resources in the wrong zone, causing confusion or errors.

Always include the --zone flag with the correct zone for your resources.

Trying to attach a disk that is in a different zone than the instance.

Disks and instances must be in the same zone to attach; otherwise, the command fails.

Create disks and instances in the same zone before attaching.

Forgetting to stop instances when not in use.

Running instances incur costs even if idle.

Stop instances with gcloud compute instances stop to save money.

Summary

Create virtual machines with 'gcloud compute instances create' specifying zone, machine type, and OS image.

Create and attach persistent disks to instances in the same zone using 'gcloud compute disks create' and 'gcloud compute instances attach-disk'.

List instances to check their status and stop them when not needed to save costs.