About Compute Engine

This section answers general questions about Compute Engine.

What is Compute Engine? What can it do?

Compute Engine is an Infrastructure-as-a-Service product offeringflexible, self-managed virtual machines (VMs) hosted on Google's infrastructure.Compute Engine includes Linux and Windows based VMs running on KVM, localand durable storage options, and a REST based API for configuration and control.The service integrates with Google Cloud technologies such asCloud Storage,App Engine,andBigQuery to extend beyond the basiccomputational capability to create more complex and sophisticatedapps.

What is a virtual CPU in Compute Engine?

On Compute Engine, each virtual CPU (vCPU) is implemented as asingle hardware hyper-thread on one of the availableCPU Platforms. On Intel Xeon processors,Intel Hyper-Threading Technology allows multiple application threads to run on each physical processor core.You configure your Compute EngineVMs with one or more of these hyper-threads as vCPUs. Themachine type specifies the number of vCPUs thatyour instance has.

You can identify the specific CPU platform for your instance using one ofthe following options:

• See what CPU platforms are available in each of theavailable regions and zones.
• Use thecompute.instances.getmethod to obtain thecpuPlatform property for one of your existinginstances.
• On Linux instances, runcat /proc/cpuinfo.

If you want to change the CPU platform for your instance, you canspecify a minimum CPU platform.

How do App Engine and Compute Engine relate to each other?

We see the two as being complementary. App Engine is Google'sPlatform-as-a-Service offering and Compute Engine is Google'sInfrastructure-as-a-Service offering. App Engine is great for runningweb-based apps, line of business apps, and mobile backends.Compute Engine is great for when you need more control of theunderlying infrastructure. For example, you might use Compute Enginewhen you have highly customized business logic or you want to run your ownstorage system.

How do I get started?

Try the Getting Started guidesfor the service. After you have finished the quickstart, read theVirtual machine instances overview tostart learning about Compute Engine.

Billing

This section answers questions about Compute Engine billing.

How does pricing and purchasing work?

Compute Engine charges based on compute instance, storage, and network use.VMs are charged on a per-second basis with a 1 minute minimum.Storage cost is calculated based on the amount of data you store.Network cost is calculated based on the amount of data transferred betweenVMs that communicate with each other and with theInternet. For more information,review our price sheet.

Do your prices include tax?

No, the price sheet does not include tax.

Support and feedback

This section answers questions about Compute Engine support and feedback.

Do you offer paid support?

Yes, we offer paid support for enterprise customers. For more information,contact oursales organization.

Do you offer a Service Level Agreement (SLA)?

Yes, we offer aCompute Engine SLA.

Where can I send feedback?

For billing-related questions, you can send questions to the appropriatesupport channel.

For feature requests and bug reports, submit an issue to ourissues tracker.

Authentication

This section answers questions about authentication and authorization.

How can I authenticate to the Compute Engine API?

How you authenticate to the Compute Engine API depends on the method used toaccess the API: client libraries, Google Cloud CLI, or REST. For moreinformation, seeAuthenticate to Compute Engine.

To authenticate apps or workloads to Google Cloud APIs, seeChoose a workload authentication method.

What are service accounts?

Aservice account is an account that represents an application, asopposed to representing an end user. These accounts can be used to authorizeCompute Engine to act on the behalf of the user to access non-sensitiveinformation. A service account is never used to access user information.Service accounts simplify the process ofauthenticating from Compute Engine to other services by handling theauthorization process for the user.

Compute Engine developers typically useCompute Engine service accounts in their applications. For moreinformation about service accounts,seeService accounts.

How do I create a service account?

Compute Engine creates a service account automatically when youcreate a new instance andspecify a service account scopefor that instance.

Projects

This section answers questions about projects in Compute Engine.

What are projects?

Aproject is a container forall Compute Engine resources. Each project is a totally compartmentalizedworld; projects don't share resources, can have different owners and users, arebilled separately, and are no more accessible to each other than your homecomputer is accessible to your neighbor's computer.

How can I create a project?

1. Sign in to your Google Account. If you don't already have one, Sign up for a new account.
2. Go to theGoogle Cloud console. When prompted, select an existing project or create a new project.Important: The name you use must be between 4 and 30 characters. When you type the name, the form will suggest a project ID, which you can edit. The project ID you use must be between 6 and 30 characters, with a lowercase letter as the first character. You can use a dash, lowercase letter, or digit for the remaining characters, but the last character cannot be a dash. You should be aware that some resource identifiers (such as project IDs) might be retained beyond the life of your project. For this reason, avoid storing sensitive information in resource identifiers....see naming guidelines
3. Follow the prompts to set up billing. If you are new to Google Cloud, then you have 91 days, $300 free trial credit to pay for your instances.

What is the difference between a project number and a project ID?

Every project can be identified in two ways: the project number or theproject ID. The project number is automatically created when you create theproject, whereas the project ID is created by you, or whoever created theproject. The project ID is optional for many services, but is required byCompute Engine. For more information, seeGoogle Cloud console Projects.

Where can I find my project ID?

You can find your project ID on theGoogle Cloud console,which provides a list of your projects and their project IDs upon entry.

Where can I request more quota for my project?

By default, all Compute Engine projects havedefault quotas for various resourcetypes. However, these default quotas can be increased on a per-project basis.Check your quota limits and usage in thequota page on theGoogle Cloud console. If you reach the limit for your resources and need morequota, make a request to increase the quota for certain resources using theIAM quotas page.You can make a request by clicking theEdit Quotas button on the top ofthe page.

Instances

This section answers questions about compute instances.

What kind of machine configuration (memory, RAM, CPU) can I choose for my instance?

Compute Engine offers several configurations for your instance. You canalso create custom configurations that match your exact instance needs. See thefull list of available options on theMachine Types page.

If I accidentally delete my instance, can I retrieve it?

No, instances that have beendeleted cannot beretrieved. However, if an instance is onlystopped, thenyou canstart it again.

What operating systems can my instances run on?

Compute Engine supports severaloperating system imagesand third-party images. Additionally, you cancreate a customized version of an imageorbuild your own image.

What are the available zones I can create my instance in?

For a list of available regions and zones, seeregions and zones.

How do I find out how much quota I have used or have left?

Check your quota limits and usage in thequota page on theGoogle Cloud console. If you reach the limit for your resources and need morequota, click theRequest increase button on thequota page and complete therequest form.

What kind of virtual CPU do I have running on my instance?

Check the specific CPU platform for your instance usingone of the following options:

• See what CPU platforms are available in each of theavailable regions and zones.
• Use thecompute.instances.getmethod to obtain thecpuPlatform property for one of your existinginstances.
• On Linux instances, runcat /proc/cpuinfo.

What are Preemptible VM instances, and how are Preemptible instances different than normal instances?

Preemptible instances are instances that you can create and run at a muchlower price than normal instances, but might stop ifCompute Engine needs to reclaim the compute capacity for allocation to other VMs.For more information, seeCreating a Preemptible VM Instance.

How can I send outbound emails from a Compute Engine instance?

Generally, Compute Engine blocks outbound traffic through theseblocked ports. However,you can set up a mail gateway through Google using SMTP. For more information,readSending Email from an Instance.

There was a host error with my virtual machine and it was restarted. What happened?

A host error (compute.instances.hostError) means that there was a hardware or software issue on the physical machine or the data center infrastructure hosting your compute instance that caused your instance to crash. A host error involving a total hardware failure or other hardware issues might prevent thelive migration of your instance. If your instance is set to automatically restart, which is the default setting, Compute Engine restarts your instance, typically within three minutes from the time the error was detected. Depending on the issue, the restart might take up to 5.5 minutes.

Occasionally, a compute instance might become unresponsive before a host error is signaled. Youcan reduce the amount of time Compute Engine waits to restart or terminate the instance bysetting the host error recovery timeout. For more information, seeSet availability policies.

Physical hardware and software failures can happen occasionally but are rare occurrences. To protect your applications and services from these potentially disruptive system events, review the following resources:

• Designing robust systems
• Patterns for scalable and resilient apps
• Creating managed instance groups

Google also offers managed services such asApp Engine and theApp Engine flexible environment.

To determine if a host error caused your VM to shut down, seeDiagnosing VM shutdowns and reboots.

Images

This section answers questions about the OS images that you can use for yourinstances.

Do I need to enable the Cloud Storage service before I can store my images externally?

Yes, to store images externally, you need to enable theCloud Storage service.

Persistent Disk

This section answers questions about storage using Persistent Disk.

How do I choose the right size for my Persistent Disk volume?

Persistent Disk performance scales with the size of the Persistent Disk volume.Use thePersistent Diskperformance chart to help decide what size disk works for you. Ifyou're not sure, read the documentation todecidehow big to make your persistentPersistent Disk volume.

Do Persistent Disk volumes cache writes?

No, Persistent Disk volumes don't cache writes. Successful completion of a writecommand occurs only after the data has been transferred to stable media.

LVM for Compute Engine

Logical Volume Manager (LVM) is not available for Google Cloud providedimages. However, if you require the flexibility of LVM, we recommend the following approaches to volume management on Compute Engine:

• Use secondary disks. You can avoid the need for root disk resizingby using secondary disks without partitions. Depending on the scenario,using secondary disks can lower the risk of an outage due to error.
• Resize the file system and partitionson a zonal persistent disk. Before you make any file system modifications,backup your disk bytaking a snapshot.In the event of failures during the file system resize, you can use thesnapshot to recover the disk.
• Use existing images that have LVM-based roots byimporting them ormigrating your existing VMs into Compute Engine.

What steps does Google take to protect my data?

SeeDisk Encryption.

Can I attach my Persistent Disk volume to more than one instance?

You can attach a Persistent Disk volume to multiple instances only if the disk is inread-only mode. An SSD Persistent Disk volume in multi-writer mode can be attachedto two N2 virtual machine (VM) instances. You cannot attach a Persistent Disk volumein both read-write mode and read-only mode at the same time. For more information,seeShare Persistent Disk volumes between VMs.

When should I use Persistent Disk versus Cloud Storage?

Both Persistent Disk and Cloud Storage can both be used to storefiles but are very different offerings. Cloud Storage is a massive filecontainer,designed to store extremely large amounts of relatively static data which canbe accessed globally, including from Compute Engine virtual machineinstances.

The following chart provides some information about the characteristicspecialties of each offering and what they are best used for.

Networking

This section answers questions about networking in Compute Engine.

Where can I find Compute Engine IP ranges?

Google Cloud publishes a JSON-formatted list of customer-usable global andregional external IP address ranges incloud.json.

• Health check IP ranges

• Cloud DNS source ranges for traffic sent toforwardingtargets oralternative nameservers

• Source ranges used byTCP forwarding forIdentity-Aware Proxy

• For information about how to determine source ranges for Google APIs andservices, seenetwork configuration forPrivate Google Access.

Why is traceroute missing hops to internet-bound destinations?

Runningtraceroute on a Compute Engine VM instance either shows onlythe destination or some hops towards internet-bound destinations. For moreinformation, seeTraceroute to internet-bounddestinations in the VPC documentation.

Zones

This section answers questions about the zones where you can use Compute Engineresources.

Do I have the option of using a regional data center in selected countries?

Yes, Compute Engine offers data centers around the world.These data center options are designed to provide lowlatency connectivity options from those regions. For specific regioninformation, including the geographic location of regions, seeRegions and zones.

How can I tell if a zone is offline?

TheCompute EngineZonessection in the Google Cloud console shows the status of each zone. You can alsoget the status of zones through thecommand-line tool by runninggcloud compute zones list, or through theCompute Engine API with thecompute.zones.listmethod.

Startup scripts

This section answers questions about startup scripts that you can use with yourinstances.

When does my custom startup script run?

Startup scriptsrun at the end of the boot process.

Infrastructure maintenance events

This section answers questions about maintenance events for your instances.

What are infrastructure maintenance events?

Compute Engine might periodically need to perform scheduled maintenance onzones that may affect your instances. By default, all instances are configuredso that these maintenance events are transparent to your apps and workloads. This may cause some performance degradation but your instances willremain online through the maintenance event. For more information, seeTransparent maintenance.

How often do scheduled infrastructure maintenance events happen?

Infrastructure maintenance events don't have a set interval between occurrences,but generally happen once every two weeks.

How do I know if an instance will be undergoing an infrastructure maintenance event?

Shortly before a maintenance event, Compute Engine changes a specialattribute in a virtual machine's metadata server before any attempts to livemigrate or stop and restart the virtual machine as part of a pendinginfrastructure maintenance event. Themaintenance-event attributeis updated before and after an event, letting you detect when theseevents are imminent. You can use this information to help automate any scriptsor commands you want to run before or after a maintenance event. For moreinformation, see theTransparent maintenance noticedocumentation.