Oracle Cloud Infrastructure Documentation

Overview of the Compute Service

Oracle Cloud Infrastructure Compute lets you provision and manage compute hosts, known as A bare metal or virtual machine (VM) compute host. The image used to launch the instance determines its operating system and other software. The shape specified during the launch process determines the number of CPUs and memory allocated to the instance.. You can launch instances as needed to meet your compute and application requirements. After you launch an instance, you can access it securely from your computer, restart it, attach and detach volumes, and terminate it when you're done with it. Any changes made to the instance's local drives are lost when you terminate it. Any saved changes to volumes attached to the instance are retained.

Oracle Cloud Infrastructure offers both Bare Metal and Virtual Machine instances:

  • Bare Metal - A bare metal compute instance gives you dedicated physical server access for highest performance and strong isolation.
  • Virtual Machine - A Virtual Machine (VM) is an independent computing environment that runs on top of physical bare metal hardware. The virtualization makes it possible to run multiple VMs that are isolated from each other. VMs are ideal for running applications that do not require the performance and resources (CPU, memory, network bandwidth, storage) of an entire physical machine.
  • An Oracle Cloud Infrastructure VM compute instance runs on the same hardware as a Bare Metal instance, leveraging the same cloud-optimized hardware, firmware, software stack, and networking infrastructure.

Be sure to review Best Practices for Your Compute Instance for important information about working with your Oracle Cloud Infrastructure Compute instance.

Components for Launching Instances

The components required to launch an instance are:

availability domain
The Oracle Cloud Infrastructure data center within your geographical region that hosts cloud resources, including your instances. You can place instances in the same or different availability domains, depending on your performance and redundancy requirements. For more information, see Regions and Availability Domains.
virtual cloud network
A virtual version of a traditional network—including subnets, route tables, and gateways—on which your instance runs. At least one cloud network has to be set up before you launch instances. For information about setting up cloud networks, see Overview of Networking.
key pair (for Linux instances)
A security mechanism required for Secure Shell (SSH) access to an instance. Before you launch an instance, you’ll need at least one key pair. For more information, see Managing Key Pairs on Linux Instances.
tags

You can apply tags to your resources to help you organize them according to your business needs. You can apply tags at the time you create a resource, or you can update the resource later with the desired tags. For general information about applying tags, see Resource Tags.

password (for Windows instances)
A security mechanism required to access an instance that uses an Oracle-provided Windows image. The first time you launch an instance using a Windows image, Oracle Cloud Infrastructure will generate an initial, one-time password that you can retrieve using the console or API. This password must be changed after you initially log on.
image
A template of a virtual hard drive that determines the operating system and other software for an instance. For details about Oracle Cloud Infrastructure platform images, see Oracle-Provided Images. You can also launch instances from:
shape
A template that determines the number of CPUs, amount of memory, and other resources allocated to a newly created instance. You choose the most appropriate shape when you launch an instance. See Compute Shapes for a list of available bare metal and VM shapes.

You can optionally attach volumes to an instance. For more information, see Overview of Block Volume.

Resource Identifiers

Each Oracle Cloud Infrastructure resource has a unique, Oracle-assigned identifier called an Oracle Cloud ID (OCID). For information about the OCID format and other ways to identify your resources, see Resource Identifiers.

Ways to Access Oracle Cloud Infrastructure

You can access Oracle Cloud Infrastructure using the Console (a browser-based interface) or the REST API. Instructions for the Console and API are included in topics throughout this guide. For a list of available SDKs, see Software Development Kits and Command Line Interface.

To access the Console, you must use a supported browser. You can use the Console link at the top of this page to go to the sign-in page. You will be prompted to enter your cloud tenant, your user name, and your password.

For general information about using the API, see REST APIs.

Authentication and Authorization

Each service in Oracle Cloud Infrastructure integrates with IAM for authentication and authorization, for all interfaces (the Console, SDK or CLI, and REST API).

An administrator in your organization needs to set up A collection of users who all need a particular type of access to a set of resources or compartment., A collection of related resources that can be accessed only by certain groups that have been given permission by an administrator in your organization., and An IAM document that specifies who has what type of access to your resources. It is used in different ways: to mean an individual statement written in the policy language; to mean a collection of statements in a single, named "policy" document (which has an Oracle Cloud ID (OCID) assigned to it); and to mean the overall body of policies your organization uses to control access to resources. that control which users can access which services, which resources, and the type of access. For example, the policies control who can create new users, create and manage the cloud network, launch instances, create buckets, download objects, etc. For more information, see Getting Started with Policies. For specific details about writing policies for each of the different services, see Policy Reference.

If you’re a regular user (not an administrator) who needs to use the Oracle Cloud Infrastructure resources that your company owns, contact your administrator to set up a user ID for you. The administrator can confirm which compartment or compartments you should be using.

Limits on Compute Resources

See Service Limits for a list of applicable limits and instructions for requesting a limit increase.

Additional limits include:

  • To attach a volume to an instance, both the instance and volume must be within the same availability domain.
  • Many Compute operations are subject to throttling.

Metadata Key Limits

Custom metadata keys (any key you define that is not ssh_authorized_keys or user_data) have the following limits:

  • Max number of metadata keys: 128
  • Max size of key name: 255 characters
  • Max size of key value: 255 characters

ssh_authorized_keys is a special key that does not have these limits, but its value is validated to conform to a public key in the OpenSSH format.

user_data has a maximum size of 16KB. For Linux instances with cloud-init configured, you can populate the user_data field with a Base64-encoded string of cloud-init user data. For more information on formats that cloud-init accepts, see cloud-init formats. On Windows instances, the user_data field can be provided but isn't used by Oracle-provided images.