What Is Amazon EC2?
Amazon EC2 (Elastic Compute Cloud) is one of the most popular and core services provided by AWS.
EC2 provides Infrastructure as a Service (IaaS), which means:
- AWS manages the physical data centers and hardware
- You rent virtual machines and control the operating system, applications, and configuration
What EC2 Primarily Enables
Amazon EC2 mainly gives you the capability to:
- Rent virtual machines → EC2 Instances
- Store virtual disks → Elastic Block Store (EBS)
- Distribute traffic across instances → Elastic Load Balancer (ELB)
- Automatically scale resources → Auto Scaling Groups (ASG)
EC2 Sizing & Configuration Options
When launching an EC2 instance, you must make several configuration decisions.
1. Operating System (OS)
Common options include:
- Linux (Amazon Linux, Ubuntu, RHEL, etc.)
- Windows Server
2. Compute Power (CPU / vCPU)
vCPU stands for virtual CPU
- A vCPU usually represents:
- One physical CPU core or
- One hyperthread of a physical core (depends on instance type)
- One physical CPU core or
Key idea:
More vCPUs allow better parallel processing and higher compute capacity.
3. Memory (RAM)
- Measured in GiB (Gibibytes), not GB
- Used for:
- Running applications
- Caching data
- In-memory workloads
Key idea:
More RAM improves performance for memory-intensive applications.
4. Storage Options
EC2 supports two main storage models.
(a) Network-Attached Storage
Includes:
- Elastic Block Store (EBS)
- Elastic File System (EFS)
Characteristics:
- Data persists even after instance stop or termination
- Network-based storage
- Slightly higher latency than local disks
(b) Hardware-Attached Storage (Instance Store)
Characteristics:
- Physically attached to the host machine
- Very high performance (often NVMe SSD)
- Data is lost when the instance stops or terminates
Best suited for:
- Temporary data
- Caches
- Buffers
- Scratch space
5. Network Configuration
Includes:
- Network bandwidth (NIC speed)
- Public IPv4 address
- Private IP address
- VPC and subnet placement
6. Security
Security Groups act as virtual firewalls- They control:
- Inbound traffic
- Outbound traffic
Security Groups operate at the instance level.
7. Bootstrap Scripts (User Data)
EC2 User Data allows scripts to run at first launch- Common uses:
- Installing packages
- Configuring services
- Automatically starting applications
Understanding EC2 Instance Types
EC2 instance types are compared based on:
- vCPU count
- Memory (GiB)
- Storage type
- Network performance
- EBS bandwidth
How to Read Instance Type Names
Example: c5d.4xlarge
c → Compute-optimized family
5 → Instance generation
d → Instance store (local NVMe storage included)
4xlarge → Instance size
When to Use Which Instance Family
t-series → Burstable workloads (testing, small services)
c-series → CPU-intensive workloads (batch jobs, APIs)
m-series → Balanced, general-purpose workloads
r-series → Memory-intensive workloads (databases, caching)
Key Takeaways
- EC2 is the backbone of compute services in AWS
- Choosing the right instance depends on:
- CPU requirements
- Memory needs
- Storage type
- Network performance
- Proper sizing helps avoid over-provisioning and unnecessary cost
References
AWS EC2 Documentation
https://docs.aws.amazon.com/ec2/AWS EC2 Instance Type Naming Convention
https://docs.aws.amazon.com/AWSEC2/latest/UserGuide/instance-types.html