Adding rpo-rto

overview.md

@@ -11,7 +11,10 @@
 - [AWS Transit Gateway](#aws-transit-gateway)
 - [Amazon EMR](#amazon-emr)
 - [Auto Scaling](#auto-scaling)
-
+- [Cloudfront](#cloudfront)
+- [Secrets Manager](#secrets-manager)
+- [Textract](#textract)
+- [RPO and RTO](#rpo-and-rto)
 ## Amazon EBS
 ---
 
@@ -97,6 +100,8 @@
 - You can use the service to store data in the AWS cloud for scalable and cost-effective storage that helps maintain
 - It stores files as native S3 objects, archives virtual tapes in Amazon Glacier and stores EBS snapshots generated by the Volume Gateway with Amazon EBS.
 
+    <img src="./images/Overview/storage-gateway.jpg" width="87%"/>
+
 ## Elastic Load Balancer 
 ---
 - Distributes incoming application or network traffic across multiple targets, such as EC2 instances containers (ECS), Lambda functions and IP addresses in multiple Availability zones
@@ -142,5 +147,48 @@
 - Configure automatic scaling for the AWS resources quickly through a scaling plan that uses <strong> Dynamic Scaling </strong>and <strong>Predictive scaling </strong>.
 - <strong><em>Useful for </em></strong>:
     - Cyclical traffic such as high use of resources during regular business hours and low use of resources
-    - On and Off traffic such as batch processing, testing and periodic analysis 
-    - Variable traffic patterns, such as software for marketing growth with periods of spiky growth
+    - On and Off traffic such as <ins>batch processing, testing and periodic analysis </ins> 
+    - Variable traffic patterns, such as software for <ins>marketing growth with periods of spiky growth </ins>
+- <Strong>Dynamic Scaling</strong>
+    - To add and remove capacity for resources to maintain resource at target value
+- <Strong>Predictive Scaling</strong>
+    - To forecast the future load demands by analyzing your historical records for a metric 
+    - <ins>Allows schedule scaling </ins> by adding or removing capacity and controls maximum capacity
+    - <ins><em> <strong>Only available for EC2 scaling groups </ins></em></strong>
+
+
+## CloudFront
+---
+
+
+
+## Secrets Manager 
+---
+
+- Helps to <ins> <i> manage, retrieve and <strong>rotate database credentials,</strong> application credentials, OAuth tokens, API keys and other secrets throughout their lifecycles 
+</ins></i>
+- Helps to <ins> improve security posture </ins>, because you <ins><strong>no longer need hard-coded credentials</strong> </ins> in application source code.
+    - Storing the credentials in Secrets Manager helps avoid possible compromise by anyone who can inspect the application or the components. 
+    - Replace hard-coded credentials with a runtime call to the Secrets Manager service to retrieve credentials with a runtime call to the Secrets Manager service to retrieve credentials dynamically when you need them. 
+
+## Textract
+---
+- A fully managed document analysis service for detecting and extracting information from scanned documents
+- Return extracted data as key-value pairs (e.g. Name: John Doe)
+- Supports virtually any type of documents
+- Pricing
+    - Pay for what you use 
+    - Charges vary for Detect Document Text API and Analyze Document API with the later being more expensive
+
+## RPO and RTO
+---
+
+- RTO (Recovery Time Object)
+    - measures how quickly the application should be available after an outage
+- RPO (Recovery Point Object)
+    - refers to how much data loss can the application can tolerate
+
+<img src="./images/Overview/rto-rpo.jpg" width="87%"/>
+
+    - Data loss is measured from most recent backup to the point of disaster. Downtime is measured from the point of disaster until fully recovered and available for service.
+