AWS CSA Prep 2

Compute & Networking :

EC2 – Elastic Compute Cloud provides VMs. Servers you call ’em. You can always customize them like processors, memory, volumes, n\w throughput. The pricing models for EC2 are,

• Reserved instances – This option is used when you know that you wanna use those web servers 24*7 and would want those instances up and running given at any point in time.
• On-Demand instance – Spin up when needed and then spin down when not needed.
• Spot-Instances – These are non-production instances which are unreliable as AWS can take ’em back when they feel so. Has to be bidden.

Elastic Load Balancing – AWS’ load balancer to distribute traffic to different instances in different AZs. Used in Auto-scaling and Fault tolerance.

Route 53 – Doman management service. To direct traffic from domain to EC2 instances.

AMI – Amazon machine images. If you don’t know what Machine Images are, go home.

Instance Store-backed instance (Ephemeral storage) – Storage provided by EC2 instances. This is wiped out when the instance is turned off.

EBS backed instance – Block storage attached to EC2 instances. Used to backup snapshots. Can provision IOPS\ optimized EBS instances to help traffic between instance and EBS volume. Min size – 1 Gib Max size – 16 Tib.  EBS volumes cannot be attached to instances in different AZs. Can be attached to only one instance at a time. Point in time snapshots a can be taken.

User responsibilities regarding EC2 instances – Security groups, Firewalls, EBS encryption available only on M3 or larger. Any instance smaller than M3 should not use EBS encryption as its a resource hog. Applying SSL cert to ELB.

AWS responsibilities – DDOS protection, Port scanning is not allowed in our own environment too. Ingress network filtering.

VPC – Isolation of resources. Internal communication allowed between resources. But for inter-VPC communication peering should be done. VPC is free of cost, yay !

There is something called EC2-Classic which is a deprecated service by AWS. They dont belong to VPCs. They have been discontinued from Dec 2013.

Route 53 – DNS hosting solution. Register\Transfer domains. can be used to route http://www.xyz.comto a CloudFront distribution\ELB\EC2\RDS etc Route 53 also is used to manage internal DNS inside VPCs. Can be used for Latency\GEO\Failover routing.