[AWS Certificate] Developer - ELB, SDK and Lambda memo

* Elastic Load Balancer (Exam Tips)

Elastic Load Balancer FAQs

Classic Load Balancer

General

Application Load Balancer

Network Load Balancer

1178578-C02NW6G1G3QD:AWS_SSH changsoopark$ ssh ec2-user@34.228.166.148 -i EC2KeyPair.pem.txt 

Last login: Mon Oct 16 23:10:59 2017 from 208.185.161.249

       __|  __|_  )

       _|  (     /   Amazon Linux AMI

      ___|\___|___|

https://aws.amazon.com/amazon-linux-ami/2017.03-release-notes/

13 package(s) needed for security, out of 33 available

Run "sudo yum update" to apply all updates.

Amazon Linux version 2017.09 is available.

[ec2-user@ip-172-31-24-42 ~]$ sudo su

[root@ip-172-31-24-42 ec2-user]# service httpd status

httpd (pid  8282) is running...

[root@ip-172-31-24-42 ec2-user]# service httpd start

Starting httpd: 

[root@ip-172-31-24-42 ec2-user]# chkconfig httpd on

[root@ip-172-31-24-42 ec2-user]# service httpd status

httpd (pid  8282) is running...

[root@ip-172-31-24-42 ec2-user]# cd /var/www/html

[root@ip-172-31-24-42 html]# ls -l

total 4

-rw-r--r-- 1 root root 185 Sep 10 23:38 index.html

[root@ip-172-31-24-42 html]# nano healthcheck.html

[root@ip-172-31-24-42 html]# ls -l

total 8

-rw-r--r-- 1 root root  28 Oct 16 23:14 healthcheck.html

-rw-r--r-- 1 root root 185 Sep 10 23:38 index.html

[root@ip-172-31-24-42 html]# 

Go to EC2 in aws.amazon.com and click on Load Balancers in left panel.

Classic Load Balancer

Next -> Select Security Group, Configure Security Settings (Next) -> 

Add Tag -> Review -> Close ->

(Edit Instance if there is no State)

- Create Application Load Balancer

-> Almost same as Classic Load Balancer.

-> Provisioning state will be turn to active after a couple of mins.

- Application Load Balancer : Preferred for HTTP/HTTPS (****)

- Classic Load Balancer (*****)

1 subnet = 1 availability zone

- Instances monitored by ELB are reported as ;

  InService, or OutofService

  

- Health Checks check the instance health by talking to it

- Have their own DNS name. You are never given an IP address.

- Read the ELB FAQ for Classic Load Balancers ***

- Delete Load Balancers after complete the test. (It would be paid service)

* SDK's - Exam Tips

https://aws.amazon.com/tools/

- Android, iOS, JavaScript (Browser)

- Java

- .NET

- Node.js

- PHP

- Python

- Ruby

- Go

- C++

Default Region - US-EAST-1

Some have default regions (JAVA)

Some do not (Node.js)

* Lambda (*** - Several questions)

Data Center - IAAS - PAAS - Containers - Serverless

The best way to get started with AWS Lambda is to work through the Getting Started Guide, part of our technical documentation. Within a few minutes, you will be able to deploy and use a AWS Lambda function.

What is Lambda?

- Data Centers

- Hardware

- Assembly Code/Protocols

- High Level Languages

- Operating System

- Application Layer/AWS APIs

- AWS Lambda 

AWS Lambda is a compute service where you can upload your code and create a Lambda function. AWS Lambda takes care of provisioning and managing the servers that you use to run the code. You don't have to worry about operating systems, patching, scaling, etc. You can use Lambda in the following ways.

- As an event-driven compute service where AWS Lambda runs your code in response to events. These events could be changes to data in an Amazon S3 bucket or an Amazon DynamoDB table.

- As a compute service to run our code in response to HTTP requests using Amazon API Gateway or API calls made using AWS SDKs. 

How to user Lambda -> refer to my articles for Alexa Skill development

http://coronasdk.tistory.com/931

What Languages?

Node.js

Java

Python

C#

How is Lambda Priced?

- Number of requests

   First 1 million requests are free. $0.20 per 1 million requests thereafter.

- Duration

  Duration is calculated from the time your code begins executing until it returns or otherwise terminates, rounded up to the nearest 100ms. The price depends on the amount of memory you allocate to your function. You are charged $0.00001667 for every GB-second used.

Why is Lambda cool?

- No Servers!

- Continuous Scaling

- Super cheap!

Lambda - Exam Tips

Lambda scales out (not up) automatically

Lambda functions are independent, 1 event = 1 function

Lambda is serverless

Know what services are serverless! (S3, API Gateway, Lambda Dynamo DB etc. ) -EC2 is not serverless.-

Lambda functions can trigger other lambda functions, 1 event can = x functions if functions trigger other functions

Architectures can get extremely complicated, AWS X-ray allows you to debug what is happening

Lambda can do things globally, you can use it to back up S3 buckets to other S3 buckets etc.

Know your triggers

(Duration time is Maximum 5 mins)