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High Lights- 6

S3​

  • S3 Storage Lens provides a centralized, organization-wide view of storage usage and activity metrics, including versioning status. When advanced metrics are enabled, the dashboard offers per-bucket insights to help identify buckets where versioning is not enabled. Scans all Regions and accounts, making it highly scalable and efficient.
  • Amazon S3 server access logging provides detailed records of requests made to a bucket. AWS recommends using CloudTrail instead for more detailed bucket and object-level logs, better storage, analysis, and automation.
  • Amazon S3 provides strong read-after-write consistency automatically—no extra cost, no impact on performance, and retains regional isolation.
  • Minimum 30 days is required before you can transition objects from S3 Standard to One Zone-IA / Standard-IA / Intelligent Tiering / Glacier.

AWS SQS​

  • Temporary queues save time and cost when using common messaging patterns like request-response.
    • Serve as lightweight channels for specific threads or processes.
    • Created and deleted with no extra cost.
    • Fully compatible with static SQS queues—no code changes needed.
  • Delay queues allow you to postpone message delivery—for example, when consumers need more time to process.

VPC​

  • Public VIF gives your on-prem router access to public AWS services (S3, DynamoDB) via Direct Connect—not public internet.
  • Private VIF connects your on-prem network to VPC resources like EC2/RDS via private IP space.
  • NAT Instance vs NAT Gateway:
    pt4-q12-i1

Elastic Load Balancer​

  • When using instance IDs as targets, ELB routes traffic to the instance’s primary private IP on the primary network interface.
  • When using IP addresses, you can use any private IP from multiple ENIs. This allows multiple apps on the same instance to share ports. Each ENI can have its own security group. The destination IP is rewritten by ELB before forwarding.

Placement Groups​

  • Spread Placement Group:
    • Instances are placed on distinct racks—each with its own network and power.
    • Recommended for small number of critical instances that must be isolated from each other.
    • Reduces risk of simultaneous hardware failure.
    • Max 7 running instances per AZ. To launch 15 instances in one group, use 3 AZs.

EC2​

  • Launch Template:
    • Replaces Launch Config. Allows multiple versions, includes AMI ID, instance type, key pair, security groups, etc.
    • Enables mixed instance types and use of both On-Demand and Spot Instances—for scale, performance, and cost optimization.
  • Launch Configuration:
    • Older instance config method. No versioning support.
  • Golden AMI:
    • A pre-hardened, patched, standardized AMI with all required security, monitoring, and logging agents installed.
  • Root EBS volume is deleted by default when the instance terminates. You can change this behavior.
    • Non-root EBS volumes persist even after instance termination.

Provisioned IOPS SSD (io1) supports up to 64,000 IOPS and meets 25,000 IOPS requirement — ✅ Best choice for I/O-intensive workloads.

✅ AWS Spot Pricing Rules​

  1. You are charged the spot price that was in effect at the beginning of each instance-hour
    (not the price at the time of termination).

  2. You are billed in one-second increments, with a 1-minute minimum.

  3. If AWS terminates your Spot Instance
    (due to price changes or capacity needs),
    you are not charged for the partial hour in which the instance is terminated.

  4. If you terminate the instance, you are charged for the partial hour.

Difference Between Dedicated Host and Instance​

Dedicated host vs instance​