final fix

README.md

@@ -1,12 +1,13 @@
 # ece1779-a2
 
 ## Overview
-This project is a python-based web application that allows manager to control worker pools, each of which is an EC2 instance. Manager itself is deployed on a single EC2 and is set to run on port 5000.The size of worker pool can be scaled manually and automatically.  All images are saved in S3 and all data is saved in RDS.
+The manager app allows manager to control the worker pool, each worker is an EC2 instance. Manager itself is deployed on a single EC2 and is set to run on port 5000.The size of worker pool can be scaled manually and automatically. All images are saved in S3 and all data is saved in RDS.
 
-It also allows users to upload images and get the processed ones with objects detected. The load of user app is balanced by Load Balancer. 
+The user app allows users to upload images and get the processed ones with objects detected. The load of user app is balanced by Load Balancer. 
 
 DNS name: ece1779-243010613.us-east-1.elb.amazonaws.com
-AMI ID: ami-0016a2318cd331666
+
+AMI ID of the user app: ami-0016a2318cd331666
 
 
 
@@ -17,6 +18,10 @@ AMI ID: ami-0016a2318cd331666
 
 ## Quick Start
 
+### Start manager instance
+
+Login into AWS console, start the manager app EC2 instance. 
+
 ### Access to AWS EC2 instance
 Use the command below to access EC2 instance. The project is placed at root directory and please use the start up script to launch. 
 ```
@@ -39,12 +44,6 @@ Manager name: admin
 Password : password
 ```
 
-## Major Dependencies
-```
-Python 3.7
-Flask 1.1.1
-Gunicorn 20.0.4
-``` 
 
 ## User app interface
 
@@ -111,10 +110,10 @@ This application exposes two endpoints below for testing purposes.
     ~~~
 
 ## Manager app interface
-The dashboard page shows two charts. The first chart shows the total CPU utilization of the worker for the past 30 minutes with the resolution of 1 minute. The second chart shows the rate of HTTP requests received by the worker in each minute for the past 30 minutes.
+The dashboard page shows two charts. The first chart shows the total CPU utilization of  workers for the past 30 minutes with the resolution of 1 minute. The second chart shows the rate of HTTP requests received by workers in each minute for the past 30 minutes.
 ![manager dashboard](documentation/figures/manager_dashboard.png)
 
-The page "Number of workers" shows the number of workers for the past 30 minutes with the resolution of 1 minute.
+The page "Number of workers" shows the number of healthy targets registered to ELB for the past 30 minutes with the resolution of 1 minute.
 ![manager workers](documentation/figures/manager_workers.png)
 
 The configuration page displays the load-balancer DNS name and the information of all the instances in the worker pool. There are four buttons on this page. Administrators can manually increase one instance by clicking the scale up button. They can manually decrease one instance by clicking the scale down button. The "Clear all" button will delete application data stored on the database as well as all images stored on S3. The "Terminate" button will terminate all the workers and then stop the
@@ -129,20 +128,20 @@ The page "Auto-scale Policy" asks administrators to input the upper and lower th
 
 The worker pool on EC2 contains workers on which runs the user app. User app will read/write data from/to AWS RDS. Pictures uploaded by users and generated by the user app will be stored on AWS S3. 
 
-Manager app on EC2 is allowed to control the work pool, which can create or terminate instances. Once a worker is created or terminated on EC2, ELB will register/de-register it. ELB automatically distributes the http requests from users to workers in the worker pool to allow each worker to handle the requests evenly.
+Manager app on EC2 is allowed to control the work pool, which can create or terminate instances. Once a worker is created or terminated on EC2, ELB will register/de-register it. ELB automatically distributes the http requests to workers in the worker pool to allow each worker to handle the requests evenly.
 
-Manager app accepts http requests from the admin users to load worker information, change the worker pool size, clear the database and S3 bucket, terminate worker instances and stop the manager instance. Manager app gets the worker information from AWS Cloud Watch.
+Manager app accepts http requests from the admin users to load worker information, change the worker pool size, clear the database and S3 bucket, terminate worker instances and stop the manager instance. Manager app gets the worker information from AWS CloudWatch.
 
-An IAM role is attached to all workers on EC2 so that they can have access to the S3 bucket, cloud watch, and elastic load balancer.
+An IAM role is attached to all workers on EC2 so that they can have access to the S3 bucket, CloudWatch, and ELB.
 
-The gunicorn application server is set up to launch the user app at port 5000. Manager app also runs at port 5000. The flask web application communicates with the db at port 3306.
+The gunicorn application server is set up to launch the user app at port 5000. Manager app also runs at port 5000. The flask web application communicates with the database at port 3306.
 
 ## Database
-![DBER](documentation/figures/a2-ER_diagram.png) 
+![DBER](documentation/figures/DBER.png) 
 
-There are four tables in the db. The User table takes username as the primary key and it stores users' credential information. The password stored is the hash of the original password concatenated with a per-user salt value. 
+There are four tables in the database. The Users table takes username as the primary key and it stores users' credential information. The password stored is the hash of the original password concatenated with a per-user salt value. 
 
-The Image table has an id incremented automatically and a foreign key referenced from the username in the user table. The image table also contains some image information, like the storage location of the image, the timestamp and the type of the image(i.e. original, processed or thumbnail). 
+The Images table has an id incremented automatically and a foreign key referenced from the username in the user table. The image table also contains some image information, like the storage location of the image, the timestamp and the type of the image(i.e. original, processed or thumbnail). 
 
 The AdminUsers table takes administrator's username as the primary key and it stores users' credential information. The password stored is the hash of the original password concatenated with a per-user salt value.