About bulk creation of VMs

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Bulk creation of virtual machine (VM) instances lets you create a large number of VMs that are identical and independent from each other. When you create VMs in bulk, you can do the following:

  • Minimize consumption of API rate limits. Requests for creating VMs in bulk consume API rate limits as if you were creating a single VM.

  • Distribute VM creation across multiple zones in a region. For regional requests, Compute Engine determines the zone to create the VMs in based on the zones that have available hardware, taking into consideration the available capacity in each zone and any of your reservations.

Compute Engine doesn't manage VMs that you create in bulk. To create a group of managed VMs, use managed instance groups.

Creating VMs in bulk versus batching API requests

Creating VMs in bulk is different from batching API requests with the instances.insert method. The following table compares these two ways of creating multiple VMs:

Functionality Batching API requests Creating VMs in bulk
Zone selection
Automatically selected based on considerations such as resource availability and quota
Manual Automatic when using the regional endpoint
Upfront validation
Request fails immediately if it is not feasible
No With capacity and quota
VM name generation
Automatically generated based on a specified name pattern
Manual Optionally generated automatically
Automatic rollback
Request automatically rolled back if Compute Engine cannot create the target number of VMs
No Optionally enabled
API rate limit
How requests affect the API rate limit
One request for each VM One request for each bulk operation

Limitations

The following list describes the limitations that apply when creating VMs in bulk:

  • Disks. You cannot create VMs that have disks that are protected by customer-supplied encryption keys (CSEK).

  • Global DNS. If you are using global DNS, there might be name conflicts because the fully qualified domain name (FQDN) doesn't contain the zone. To avoid this, use zonal DNS. If you cannot switch to zonal DNS, avoid using the same name pattern across different regions. For more information, see Types of internal DNS names.

  • Machine images. You cannot create VMs from machine images.

  • Number of VMs. You can create up to 1,000 VMs with each call. Also, a maximum of 1,200 operations can occur simultaneously at any time. This simultaneous operation limit is shared between instances.insert and instances.bulkInsert.

  • Sole-tenant nodes. You cannot create VMs that use sole-tenant node affinity labels.

  • VM properties. All VM properties, except their names, must be identical. You cannot use VM properties that are mutually exclusive between VMs, which include but are not limited to custom hostnames, static external IP addresses, and static internal IP addresses.

Audit logs

Compute Engine logs information about the bulk VM creation to the Admin Activity audit log when you make the API call and when the API call completes.

Compute Engine also creates separate audit logs for each VM. You can find the audit log for a single VM by matching the value of protoPayload.resourceName with the VM name generated by the naming pattern that you specify with the request.

Pricing

There are no additional charges for using bulk VM creation. As with creating single VMs, billing begins when you create the VMs.

You are not billed for any VMs that Compute Engine fails to create.

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