Dedicated Instances

aws/billing aws/compute aws/concept

💡 Definition

Dedicated Instances are Amazon EC2 instances that run in a VPC on hardware that is dedicated to a single AWS customer. Your Dedicated Instances are physically isolated at the host hardware level from instances that belong to other AWS accounts.

🔑 Key Concepts

Hardware Isolation: Provides physical isolation of your instances from other customers' instances.
No Instance Placement Control: Unlike Dedicated Hosts, you do not have control over instance placement on a specific physical server, nor do you have visibility into the sockets and cores of the underlying hardware.
Instance Tenancy: You specify "Dedicated" tenancy when launching an instance or setting the default tenancy for a VPC.
Compliance: Primarily used to meet specific compliance or regulatory requirements that mandate physical isolation of workloads.

⚙️ How it Works

When you choose Dedicated Instance tenancy for an EC2 instance, AWS ensures that it runs on hardware that is reserved for your account alone. AWS manages the allocation of your instances to dedicated hardware. You pay for your Dedicated Instances whether they are running or stopped.

🎯 Use Cases

Regulatory Compliance: For workloads that have strict physical isolation requirements.
Licensing Restrictions: Can be used for some "Bring Your Own License" (BYOL) scenarios, though Dedicated Hosts offer more direct control for highly restrictive licenses.
Predictable Performance: While not the primary purpose, dedicated hardware can sometimes offer more consistent performance compared to shared tenancy.

💰 Pricing Model

Higher Cost: Dedicated Instances are more expensive than On-Demand Instances or Reserved Instances on shared tenancy.
Billing: Billed hourly, regardless of whether the instance is running or stopped.

📝 Exam Tips (CLF-C02)

Keywords: "Dedicated to a single customer", "Physical isolation", "No placement control".
Remember the key difference from Dedicated Hosts: With Dedicated Instances, you get dedicated hardware, but AWS manages placement; with Dedicated Hosts, you get dedicated hardware and you control instance placement (important for some BYOL).
Chosen primarily for compliance reasons requiring physical isolation.

See Also: * Dedicated Hosts * EC2 * On-Demand Instances * Reserved Instances * VPC * BYOL